Add parser support for placeholders (#9364)

packages/babel-parser/src/parser/expression.js

@@ -1048,19 +1048,8 @@ export default class ExpressionParser extends LValParser {
     if (isPrivate) {
       this.expectOnePlugin(["classPrivateProperties", "classPrivateMethods"]);
       const node = this.startNode();
-      const columnHashEnd = this.state.end;
       this.next();
-      const columnIdentifierStart = this.state.start;
+      this.assertNoSpace("Unexpected space between # and identifier");
-
-      const spacesBetweenHashAndIdentifier =
-        columnIdentifierStart - columnHashEnd;
-      if (spacesBetweenHashAndIdentifier != 0) {
-        this.raise(
-          columnIdentifierStart,
-          "Unexpected space between # and identifier",
-        );
-      }
-
       node.id = this.parseIdentifier(true);
       return this.finishNode(node, "PrivateName");
     } else {

packages/babel-parser/src/parser/statement.js

@@ -416,15 +416,24 @@ export default class StatementParser extends ExpressionParser {
 
     if (this.isLineTerminator()) {
       node.label = null;
-    } else if (!this.match(tt.name)) {
-      this.unexpected();
     } else {
       node.label = this.parseIdentifier();
       this.semicolon();
     }
 
-    // Verify that there is an actual destination to break or
+    this.verifyBreakContinue(node, keyword);
-    // continue to.
+
+    return this.finishNode(
+      node,
+      isBreak ? "BreakStatement" : "ContinueStatement",
+    );
+  }
+
+  verifyBreakContinue(
+    node: N.BreakStatement | N.ContinueStatement,
+    keyword: string,
+  ) {
+    const isBreak = keyword === "break";
     let i;
     for (i = 0; i < this.state.labels.length; ++i) {
       const lab = this.state.labels[i];
@@ -436,10 +445,6 @@ export default class StatementParser extends ExpressionParser {
     if (i === this.state.labels.length) {
       this.raise(node.start, "Unsyntactic " + keyword);
     }
-    return this.finishNode(
-      node,
-      isBreak ? "BreakStatement" : "ContinueStatement",
-    );
   }
 
   parseDebuggerStatement(node: N.DebuggerStatement): N.DebuggerStatement {
@@ -800,7 +805,7 @@ export default class StatementParser extends ExpressionParser {
   parseExpressionStatement(
     node: N.ExpressionStatement,
     expr: N.Expression,
-  ): N.ExpressionStatement {
+  ): N.Statement {
     node.expression = expr;
     this.semicolon();
     return this.finishNode(node, "ExpressionStatement");
@@ -1024,6 +1029,7 @@ export default class StatementParser extends ExpressionParser {
   ): T {
     const isStatement = statement & FUNC_STATEMENT;
     const isHangingStatement = statement & FUNC_HANGING_STATEMENT;
+    const requireId = !!isStatement && !(statement & FUNC_NULLABLE_ID);
 
     this.initFunction(node, isAsync);
 
@@ -1036,10 +1042,7 @@ export default class StatementParser extends ExpressionParser {
     node.generator = this.eat(tt.star);
 
     if (isStatement) {
-      node.id =
+      node.id = this.parseFunctionId(requireId);
-        statement & FUNC_NULLABLE_ID && !this.match(tt.name)
-          ? null
-          : this.parseIdentifier();
       if (node.id && !isHangingStatement) {
         // If it is a regular function declaration in sloppy mode, then it is
         // subject to Annex B semantics (BIND_FUNCTION). Otherwise, the binding
@@ -1067,7 +1070,7 @@ export default class StatementParser extends ExpressionParser {
     this.scope.enter(functionFlags(node.async, node.generator));
 
     if (!isStatement) {
-      node.id = this.match(tt.name) ? this.parseIdentifier() : null;
+      node.id = this.parseFunctionId();
     }
 
     this.parseFunctionParams(node);
@@ -1090,6 +1093,10 @@ export default class StatementParser extends ExpressionParser {
     return node;
   }
 
+  parseFunctionId(requireId?: boolean): ?N.Identifier {
+    return requireId || this.match(tt.name) ? this.parseIdentifier() : null;
+  }
+
   parseFunctionParams(node: N.Function, allowModifiers?: boolean): void {
     const oldInParameters = this.state.inParameters;
     this.state.inParameters = true;
@@ -1122,7 +1129,7 @@ export default class StatementParser extends ExpressionParser {
 
     this.parseClassId(node, isStatement, optionalId);
     this.parseClassSuper(node);
-    this.parseClassBody(node);
+    node.body = this.parseClassBody(!!node.superClass);
 
     this.state.strict = oldStrict;
 
@@ -1149,7 +1156,7 @@ export default class StatementParser extends ExpressionParser {
     );
   }
 
-  parseClassBody(node: N.Class): void {
+  parseClassBody(constructorAllowsSuper: boolean): N.ClassBody {
     this.state.classLevel++;
 
     const state = { hadConstructor: false };
@@ -1159,8 +1166,6 @@ export default class StatementParser extends ExpressionParser {
 
     this.expect(tt.braceL);
 
-    const constructorAllowsSuper = node.superClass !== null;
-
     // For the smartPipelines plugin: Disable topic references from outer
     // contexts within the class body. They are permitted in test expressions,
     // outside of the class body.
@@ -1212,9 +1217,9 @@ export default class StatementParser extends ExpressionParser {
       );
     }
 
-    node.body = this.finishNode(classBody, "ClassBody");
-
     this.state.classLevel--;
+
+    return this.finishNode(classBody, "ClassBody");
   }
 
   parseClassMember(

packages/babel-parser/src/parser/util.js

@@ -113,6 +113,13 @@ export default class UtilParser extends Tokenizer {
     this.eat(type) || this.unexpected(pos, type);
   }
 
+  // Throws if the current token and the prev one are separated by a space.
+  assertNoSpace(message: string = "Unexpected space."): void {
+    if (this.state.start > this.state.lastTokEnd) {
+      this.raise(this.state.lastTokEnd, message);
+    }
+  }
+
   // Raise an unexpected token error. Can take the expected token type
   // instead of a message string.
 

packages/babel-parser/src/plugin-utils.js

@@ -88,12 +88,17 @@ import estree from "./plugins/estree";
 import flow from "./plugins/flow";
 import jsx from "./plugins/jsx";
 import typescript from "./plugins/typescript";
+import placeholders from "./plugins/placeholders";
 
-// NOTE: estree must load first; flow and typescript must load last.
+// NOTE: order is important. estree must come first; placeholders must come last.
-export const mixinPluginNames = ["estree", "jsx", "flow", "typescript"];
 export const mixinPlugins: { [name: string]: MixinPlugin } = {
   estree,
   jsx,
   flow,
   typescript,
+  placeholders,
 };
+
+export const mixinPluginNames: $ReadOnlyArray<string> = Object.keys(
+  mixinPlugins,
+);

packages/babel-parser/src/plugins/placeholders.js

@@ -0,0 +1,315 @@
+// @flow
+
+import * as charCodes from "charcodes";
+
+import { types as tt, TokenType } from "../tokenizer/types";
+import type Parser from "../parser";
+import * as N from "../types";
+
+tt.placeholder = new TokenType("%%", { startsExpr: true });
+
+export type PlaceholderTypes =
+  | "Identifier"
+  | "StringLiteral"
+  | "Expression"
+  | "Statement"
+  | "Declaration"
+  | "BlockStatement"
+  | "ClassBody"
+  | "Pattern";
+
+// $PropertyType doesn't support enums. Use a fake "switch" (GetPlaceholderNode)
+//type MaybePlaceholder<T: PlaceholderTypes> = $PropertyType<N, T> | N.Placeholder<T>;
+
+type _Switch<Value, Cases, Index> = $Call<
+  (
+    $ElementType<$ElementType<Cases, Index>, 0>,
+  ) => $ElementType<$ElementType<Cases, Index>, 1>,
+  Value,
+>;
+type $Switch<Value, Cases> = _Switch<Value, Cases, *>;
+
+type NodeOf<T: PlaceholderTypes> = $Switch<
+  T,
+  [
+    ["Identifier", N.Identifier],
+    ["StringLiteral", N.StringLiteral],
+    ["Expression", N.Expression],
+    ["Statement", N.Statement],
+    ["Declaration", N.Declaration],
+    ["BlockStatement", N.BlockStatement],
+    ["ClassBody", N.ClassBody],
+    ["Pattern", N.Pattern],
+  ],
+>;
+
+// Placeholder<T> breaks everything, because its type is incompatible with
+// the substituted nodes.
+type MaybePlaceholder<T: PlaceholderTypes> = NodeOf<T>; // | Placeholder<T>
+
+export default (superClass: Class<Parser>): Class<Parser> =>
+  class extends superClass {
+    parsePlaceholder<T: PlaceholderTypes>(
+      expectedNode: T,
+    ): /*?N.Placeholder<T>*/ ?MaybePlaceholder<T> {
+      if (this.match(tt.placeholder)) {
+        const node = this.startNode();
+        this.next();
+        this.assertNoSpace("Unexpected space in placeholder.");
+
+        // We can't use this.parseIdentifier because
+        // we don't want nested placeholders.
+        node.name = super.parseIdentifier(/* liberal */ true);
+
+        this.assertNoSpace("Unexpected space in placeholder.");
+        this.expect(tt.placeholder);
+        return this.finishPlaceholder(node, expectedNode);
+      }
+    }
+
+    finishPlaceholder<T: PlaceholderTypes>(
+      node: N.Node,
+      expectedNode: T,
+    ): /*N.Placeholder<T>*/ MaybePlaceholder<T> {
+      node.expectedNode = expectedNode;
+      return this.finishNode(node, "Placeholder");
+    }
+
+    /* ============================================================ *
+     * tokenizer/index.js                                           *
+     * ============================================================ */
+
+    getTokenFromCode(code: number) {
+      if (
+        code === charCodes.percentSign &&
+        this.state.input.charCodeAt(this.state.pos + 1) ===
+          charCodes.percentSign
+      ) {
+        return this.finishOp(tt.placeholder, 2);
+      }
+
+      return super.getTokenFromCode(...arguments);
+    }
+
+    /* ============================================================ *
+     * parser/expression.js                                         *
+     * ============================================================ */
+
+    parseExprAtom(): MaybePlaceholder<"Expression"> {
+      return (
+        this.parsePlaceholder("Expression") || super.parseExprAtom(...arguments)
+      );
+    }
+
+    parseIdentifier(): MaybePlaceholder<"Identifier"> {
+      // NOTE: This function only handles identifiers outside of
+      // expressions and binding patterns, since they are already
+      // handled by the parseExprAtom and parseBindingAtom functions.
+      // This is needed, for example, to parse "class %%NAME%% {}".
+      return (
+        this.parsePlaceholder("Identifier") ||
+        super.parseIdentifier(...arguments)
+      );
+    }
+
+    checkReservedWord(word: string): void {
+      // Sometimes we call #checkReservedWord(node.name), expecting
+      // that node is an Identifier. If it is a Placeholder, name
+      // will be undefined.
+      if (word !== undefined) super.checkReservedWord(...arguments);
+    }
+
+    /* ============================================================ *
+     * parser/lval.js                                               *
+     * ============================================================ */
+
+    parseBindingAtom(): MaybePlaceholder<"Pattern"> {
+      return (
+        this.parsePlaceholder("Pattern") || super.parseBindingAtom(...arguments)
+      );
+    }
+
+    checkLVal(expr: N.Expression): void {
+      if (expr.type !== "Placeholder") super.checkLVal(...arguments);
+    }
+
+    toAssignable(node: N.Node): N.Node {
+      if (
+        node &&
+        node.type === "Placeholder" &&
+        node.expectedNode === "Expression"
+      ) {
+        node.expectedNode = "Pattern";
+        return node;
+      }
+      return super.toAssignable(...arguments);
+    }
+
+    /* ============================================================ *
+     * parser/statement.js                                          *
+     * ============================================================ */
+
+    verifyBreakContinue(node: N.BreakStatement | N.ContinueStatement) {
+      if (node.label && node.label.type === "Placeholder") return;
+      super.verifyBreakContinue(...arguments);
+    }
+
+    parseExpressionStatement(
+      node: MaybePlaceholder<"Statement">,
+      expr: N.Expression,
+    ): MaybePlaceholder<"Statement"> {
+      if (
+        expr.type !== "Placeholder" ||
+        (expr.extra && expr.extra.parenthesized)
+      ) {
+        return super.parseExpressionStatement(...arguments);
+      }
+
+      if (this.match(tt.colon)) {
+        const stmt: N.LabeledStatement = node;
+        stmt.label = this.finishPlaceholder(expr, "Identifier");
+        this.next();
+        stmt.body = this.parseStatement("label");
+        return this.finishNode(stmt, "LabeledStatement");
+      }
+
+      this.semicolon();
+
+      node.name = expr.name;
+      return this.finishPlaceholder(node, "Statement");
+    }
+
+    parseBlock(): MaybePlaceholder<"BlockStatement"> {
+      return (
+        this.parsePlaceholder("BlockStatement") ||
+        super.parseBlock(...arguments)
+      );
+    }
+
+    parseFunctionId(): ?MaybePlaceholder<"Identifier"> {
+      return (
+        this.parsePlaceholder("Identifier") ||
+        super.parseFunctionId(...arguments)
+      );
+    }
+
+    parseClass<T: N.Class>(
+      node: T,
+      isStatement: /* T === ClassDeclaration */ boolean,
+      optionalId?: boolean,
+    ): T {
+      const type = isStatement ? "ClassDeclaration" : "ClassExpression";
+
+      this.next();
+      this.takeDecorators(node);
+
+      const placeholder = this.parsePlaceholder("Identifier");
+      if (placeholder) {
+        if (
+          this.match(tt._extends) ||
+          this.match(tt.placeholder) ||
+          this.match(tt.braceL)
+        ) {
+          node.id = placeholder;
+        } else if (optionalId || !isStatement) {
+          node.id = null;
+          node.body = this.finishPlaceholder(placeholder, "ClassBody");
+          return this.finishNode(node, type);
+        } else {
+          this.unexpected(null, "A class name is required");
+        }
+      } else {
+        this.parseClassId(node, isStatement, optionalId);
+      }
+
+      this.parseClassSuper(node);
+      node.body =
+        this.parsePlaceholder("ClassBody") ||
+        this.parseClassBody(!!node.superClass);
+      return this.finishNode(node, type);
+    }
+
+    parseExport(node: N.Node): N.Node {
+      const placeholder = this.parsePlaceholder("Identifier");
+      if (!placeholder) return super.parseExport(...arguments);
+
+      if (!this.isContextual("from") && !this.match(tt.comma)) {
+        // export %%DECL%%;
+        node.specifiers = [];
+        node.source = null;
+        node.declaration = this.finishPlaceholder(placeholder, "Declaration");
+        return this.finishNode(node, "ExportNamedDeclaration");
+      }
+
+      // export %%NAME%% from "foo";
+      this.expectPlugin("exportDefaultFrom");
+      const specifier = this.startNode();
+      specifier.exported = placeholder;
+      node.specifiers = [this.finishNode(specifier, "ExportDefaultSpecifier")];
+
+      return super.parseExport(node);
+    }
+
+    maybeParseExportDefaultSpecifier(node: N.Node): boolean {
+      if (node.specifiers && node.specifiers.length > 0) {
+        // "export %%NAME%%" has already been parsed by #parseExport.
+        return true;
+      }
+      return super.maybeParseExportDefaultSpecifier(...arguments);
+    }
+
+    checkExport(node: N.ExportNamedDeclaration): void {
+      const { specifiers } = node;
+      if (specifiers && specifiers.length) {
+        node.specifiers = specifiers.filter(
+          node => node.exported.type === "Placeholder",
+        );
+      }
+      super.checkExport(node);
+      node.specifiers = specifiers;
+    }
+
+    parseImport(
+      node: N.Node,
+    ): N.ImportDeclaration | N.TsImportEqualsDeclaration {
+      const placeholder = this.parsePlaceholder("Identifier");
+      if (!placeholder) return super.parseImport(...arguments);
+
+      node.specifiers = [];
+
+      if (!this.isContextual("from") && !this.match(tt.comma)) {
+        // import %%STRING%%;
+        node.source = this.finishPlaceholder(placeholder, "StringLiteral");
+        this.semicolon();
+        return this.finishNode(node, "ImportDeclaration");
+      }
+
+      // import %%DEFAULT%% ...
+      const specifier = this.startNodeAtNode(placeholder);
+      specifier.local = placeholder;
+      this.finishNode(specifier, "ImportDefaultSpecifier");
+      node.specifiers.push(specifier);
+
+      if (this.eat(tt.comma)) {
+        // import %%DEFAULT%%, * as ...
+        const hasStarImport = this.maybeParseStarImportSpecifier(node);
+
+        // import %%DEFAULT%%, { ...
+        if (!hasStarImport) this.parseNamedImportSpecifiers(node);
+      }
+
+      this.expectContextual("from");
+      node.source = this.parseImportSource();
+      this.semicolon();
+      return this.finishNode(node, "ImportDeclaration");
+    }
+
+    parseImportSource(): MaybePlaceholder<"StringLiteral"> {
+      // import ... from %%STRING%%;
+
+      return (
+        this.parsePlaceholder("StringLiteral") ||
+        super.parseImportSource(...arguments)
+      );
+    }
+  };

packages/babel-parser/src/types.js

@@ -3,6 +3,7 @@
 import type { SourceType } from "./options";
 import type { Token } from "./tokenizer";
 import type { SourceLocation } from "./util/location";
+import type { PlaceholderTypes } from "./plugins/placeholders";
 
 /*
  * If making any changes to the AST, update:
@@ -45,6 +46,7 @@ export type Pattern =
   | ArrayPattern
   | RestElement
   | AssignmentPattern;
+//| Placeholder<"Pattern">;
 export type Declaration =
   | VariableDeclaration
   | ClassDeclaration
@@ -53,6 +55,8 @@ export type Declaration =
   | TsTypeAliasDeclaration
   | TsEnumDeclaration
   | TsModuleDeclaration;
+// | Placeholder<"Declaration">;
+
 export type DeclarationBase = NodeBase & {
   // TypeScript allows declarations to be prefixed by `declare`.
   //TODO: a FunctionDeclaration is never "declare", because it's a TSDeclareFunction instead.
@@ -78,6 +82,7 @@ export type Identifier = PatternBase & {
   // TypeScript only. Used in case of an optional parameter.
   optional?: ?true,
 };
+// | Placeholder<"Identifier">;
 
 export type PrivateName = NodeBase & {
   type: "PrivateName",
@@ -188,6 +193,7 @@ export type BlockStatement = NodeBase & {
   body: Array<Statement>, // TODO: $ReadOnlyArray
   directives: $ReadOnlyArray<Directive>,
 };
+// | Placeholder<"BlockStatement">;
 
 export type EmptyStatement = NodeBase & {
   type: "EmptyStatement",
@@ -682,6 +688,7 @@ export type ClassBody = NodeBase & {
   type: "ClassBody",
   body: Array<ClassMember | TsIndexSignature>, // TODO: $ReadOnlyArray
 };
+// | Placeholder<"ClassBody">;
 
 export type ClassMemberBase = NodeBase &
   HasDecorators & {
@@ -1421,6 +1428,16 @@ export type TsNonNullExpression = NodeBase & {
   expression: Expression,
 };
 
+// ================
+// Babel placeholders %%foo%%
+// ================
+
+export type Placeholder<N: PlaceholderTypes> = NodeBase & {
+  type: "Placeholder",
+  id: Identifier,
+  expectedNode: N,
+};
+
 // ================
 // Other
 // ================

packages/babel-parser/test/fixtures/experimental/class-private-methods/failure-spaces/options.json

@@ -1,4 +1,4 @@
 {
-  "throws": "Unexpected space between # and identifier (2:5)",
+  "throws": "Unexpected space between # and identifier (2:3)",
   "plugins": ["classPrivateMethods"]
 }

packages/babel-parser/test/fixtures/experimental/class-private-properties/failure-spaces/options.json

@@ -1,4 +1,4 @@
 {
-  "throws": "Unexpected space between # and identifier (2:5)",
+  "throws": "Unexpected space between # and identifier (2:3)",
   "plugins": ["classPrivateMethods"]
 }

packages/babel-parser/test/fixtures/placeholders/_errors/no-plugin/input.js

@@ -0,0 +1 @@
+%%FOO%%

packages/babel-parser/test/fixtures/placeholders/_errors/no-plugin/options.json

@@ -0,0 +1,4 @@
+{
+  "plugins": [],
+  "throws": "Unexpected token (1:0)"
+}

packages/babel-parser/test/fixtures/placeholders/_errors/space-after/input.js

@@ -0,0 +1 @@
+%%FOO %%

packages/babel-parser/test/fixtures/placeholders/_errors/space-after/options.json

@@ -0,0 +1,4 @@
+{
+  "plugins": ["placeholders"],
+  "throws": "Unexpected space in placeholder. (1:5)"
+}

packages/babel-parser/test/fixtures/placeholders/_errors/space-before/input.js

@@ -0,0 +1 @@
+%% FOO%%

packages/babel-parser/test/fixtures/placeholders/_errors/space-before/options.json

@@ -0,0 +1,4 @@
+{
+  "plugins": ["placeholders"],
+  "throws": "Unexpected space in placeholder. (1:2)"
+}

packages/babel-parser/test/fixtures/placeholders/arrow/async-parenless/input.js

@@ -0,0 +1 @@
+async %%PARAM%% => %%BODY%%;

packages/babel-parser/test/fixtures/placeholders/arrow/async-parenless/options.json

@@ -0,0 +1,4 @@
+{
+  "plugins": ["placeholders"],
+  "throws": "Unexpected token, expected \";\" (1:6)"
+}

packages/babel-parser/test/fixtures/placeholders/arrow/async/input.js

@@ -0,0 +1 @@
+async (%%PARAM%%) => %%BODY%%;

packages/babel-parser/test/fixtures/placeholders/arrow/async/output.json

@@ -0,0 +1,136 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 30,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 30
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 30,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 30
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start": 0,
+        "end": 30,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 30
+          }
+        },
+        "expression": {
+          "type": "ArrowFunctionExpression",
+          "start": 0,
+          "end": 29,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 0
+            },
+            "end": {
+              "line": 1,
+              "column": 29
+            }
+          },
+          "id": null,
+          "generator": false,
+          "async": true,
+          "params": [
+            {
+              "type": "Placeholder",
+              "start": 7,
+              "end": 16,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 7
+                },
+                "end": {
+                  "line": 1,
+                  "column": 16
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 9,
+                "end": 14,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 9
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 14
+                  },
+                  "identifierName": "PARAM"
+                },
+                "name": "PARAM"
+              },
+              "expectedNode": "Pattern"
+            }
+          ],
+          "body": {
+            "type": "Placeholder",
+            "start": 21,
+            "end": 29,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 21
+              },
+              "end": {
+                "line": 1,
+                "column": 29
+              }
+            },
+            "name": {
+              "type": "Identifier",
+              "start": 23,
+              "end": 27,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 23
+                },
+                "end": {
+                  "line": 1,
+                  "column": 27
+                },
+                "identifierName": "BODY"
+              },
+              "name": "BODY"
+            },
+            "expectedNode": "Expression"
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/arrow/sync-parenless/input.js

@@ -0,0 +1 @@
+%%PARAM%% => %%BODY%%;

packages/babel-parser/test/fixtures/placeholders/arrow/sync-parenless/options.json

@@ -0,0 +1,4 @@
+{
+  "plugins": ["placeholders"],
+  "throws": "Unexpected token, expected \";\" (1:10)"
+}

packages/babel-parser/test/fixtures/placeholders/arrow/sync/input.js

@@ -0,0 +1 @@
+(%%PARAM%%) => %%BODY%%;

packages/babel-parser/test/fixtures/placeholders/arrow/sync/output.json

@@ -0,0 +1,136 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 24,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 24
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 24,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 24
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start": 0,
+        "end": 24,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 24
+          }
+        },
+        "expression": {
+          "type": "ArrowFunctionExpression",
+          "start": 0,
+          "end": 23,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 0
+            },
+            "end": {
+              "line": 1,
+              "column": 23
+            }
+          },
+          "id": null,
+          "generator": false,
+          "async": false,
+          "params": [
+            {
+              "type": "Placeholder",
+              "start": 1,
+              "end": 10,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 1
+                },
+                "end": {
+                  "line": 1,
+                  "column": 10
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 3,
+                "end": 8,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 3
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 8
+                  },
+                  "identifierName": "PARAM"
+                },
+                "name": "PARAM"
+              },
+              "expectedNode": "Pattern"
+            }
+          ],
+          "body": {
+            "type": "Placeholder",
+            "start": 15,
+            "end": 23,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 15
+              },
+              "end": {
+                "line": 1,
+                "column": 23
+              }
+            },
+            "name": {
+              "type": "Identifier",
+              "start": 17,
+              "end": 21,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 17
+                },
+                "end": {
+                  "line": 1,
+                  "column": 21
+                },
+                "identifierName": "BODY"
+              },
+              "name": "BODY"
+            },
+            "expectedNode": "Expression"
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/class/body_expression/input.js

@@ -0,0 +1 @@
+void class %%BODY%%

packages/babel-parser/test/fixtures/placeholders/class/body_expression/output.json

@@ -0,0 +1,116 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 19,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 19
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 19,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 19
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start": 0,
+        "end": 19,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 19
+          }
+        },
+        "expression": {
+          "type": "UnaryExpression",
+          "start": 0,
+          "end": 19,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 0
+            },
+            "end": {
+              "line": 1,
+              "column": 19
+            }
+          },
+          "operator": "void",
+          "prefix": true,
+          "argument": {
+            "type": "ClassExpression",
+            "start": 5,
+            "end": 19,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 5
+              },
+              "end": {
+                "line": 1,
+                "column": 19
+              }
+            },
+            "id": null,
+            "body": {
+              "type": "Placeholder",
+              "start": 11,
+              "end": 19,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 11
+                },
+                "end": {
+                  "line": 1,
+                  "column": 19
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 13,
+                "end": 17,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 13
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 17
+                  },
+                  "identifierName": "BODY"
+                },
+                "name": "BODY"
+              },
+              "expectedNode": "ClassBody"
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/class/body_statement/input.js

@@ -0,0 +1 @@
+class Cl %%BODY%%

packages/babel-parser/test/fixtures/placeholders/class/body_statement/output.json

@@ -0,0 +1,101 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 17,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 17
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 17,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 17
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start": 0,
+        "end": 17,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 17
+          }
+        },
+        "id": {
+          "type": "Identifier",
+          "start": 6,
+          "end": 8,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 6
+            },
+            "end": {
+              "line": 1,
+              "column": 8
+            },
+            "identifierName": "Cl"
+          },
+          "name": "Cl"
+        },
+        "superClass": null,
+        "body": {
+          "type": "Placeholder",
+          "start": 9,
+          "end": 17,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 9
+            },
+            "end": {
+              "line": 1,
+              "column": 17
+            }
+          },
+          "name": {
+            "type": "Identifier",
+            "start": 11,
+            "end": 15,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 11
+              },
+              "end": {
+                "line": 1,
+                "column": 15
+              },
+              "identifierName": "BODY"
+            },
+            "name": "BODY"
+          },
+          "expectedNode": "ClassBody"
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/class/decorators/input.js

@@ -0,0 +1,2 @@
+@(%%FOO%%)
+class A {}

packages/babel-parser/test/fixtures/placeholders/class/decorators/options.json

@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    "placeholders",
+    ["decorators", { "decoratorsBeforeExport": true }]
+  ]
+}

packages/babel-parser/test/fixtures/placeholders/class/decorators/output.json

@@ -0,0 +1,134 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 21,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 2,
+      "column": 10
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 21,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 2,
+        "column": 10
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start": 0,
+        "end": 21,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 2,
+            "column": 10
+          }
+        },
+        "decorators": [
+          {
+            "type": "Decorator",
+            "start": 0,
+            "end": 10,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 0
+              },
+              "end": {
+                "line": 1,
+                "column": 10
+              }
+            },
+            "expression": {
+              "type": "Placeholder",
+              "start": 2,
+              "end": 9,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 2
+                },
+                "end": {
+                  "line": 1,
+                  "column": 9
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 4,
+                "end": 7,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 4
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 7
+                  },
+                  "identifierName": "FOO"
+                },
+                "name": "FOO"
+              },
+              "expectedNode": "Expression"
+            }
+          }
+        ],
+        "id": {
+          "type": "Identifier",
+          "start": 17,
+          "end": 18,
+          "loc": {
+            "start": {
+              "line": 2,
+              "column": 6
+            },
+            "end": {
+              "line": 2,
+              "column": 7
+            },
+            "identifierName": "A"
+          },
+          "name": "A"
+        },
+        "superClass": null,
+        "body": {
+          "type": "ClassBody",
+          "start": 19,
+          "end": 21,
+          "loc": {
+            "start": {
+              "line": 2,
+              "column": 8
+            },
+            "end": {
+              "line": 2,
+              "column": 10
+            }
+          },
+          "body": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/class/id-body/input.js

@@ -0,0 +1 @@
+class %%ID%% %%BODY%%

packages/babel-parser/test/fixtures/placeholders/class/id-body/output.json

@@ -0,0 +1,117 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 21,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 21
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 21,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 21
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start": 0,
+        "end": 21,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 21
+          }
+        },
+        "id": {
+          "type": "Placeholder",
+          "start": 6,
+          "end": 12,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 6
+            },
+            "end": {
+              "line": 1,
+              "column": 12
+            }
+          },
+          "name": {
+            "type": "Identifier",
+            "start": 8,
+            "end": 10,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 8
+              },
+              "end": {
+                "line": 1,
+                "column": 10
+              },
+              "identifierName": "ID"
+            },
+            "name": "ID"
+          },
+          "expectedNode": "Identifier"
+        },
+        "superClass": null,
+        "body": {
+          "type": "Placeholder",
+          "start": 13,
+          "end": 21,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 13
+            },
+            "end": {
+              "line": 1,
+              "column": 21
+            }
+          },
+          "name": {
+            "type": "Identifier",
+            "start": 15,
+            "end": 19,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 15
+              },
+              "end": {
+                "line": 1,
+                "column": 19
+              },
+              "identifierName": "BODY"
+            },
+            "name": "BODY"
+          },
+          "expectedNode": "ClassBody"
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/class/id-super-body/input.js

@@ -0,0 +1 @@
+class %%ID%% extends %%SUPER%% %%BODY%%

packages/babel-parser/test/fixtures/placeholders/class/id-super-body/output.json

@@ -0,0 +1,149 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 39,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 39
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 39,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 39
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start": 0,
+        "end": 39,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 39
+          }
+        },
+        "id": {
+          "type": "Placeholder",
+          "start": 6,
+          "end": 12,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 6
+            },
+            "end": {
+              "line": 1,
+              "column": 12
+            }
+          },
+          "name": {
+            "type": "Identifier",
+            "start": 8,
+            "end": 10,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 8
+              },
+              "end": {
+                "line": 1,
+                "column": 10
+              },
+              "identifierName": "ID"
+            },
+            "name": "ID"
+          },
+          "expectedNode": "Identifier"
+        },
+        "superClass": {
+          "type": "Placeholder",
+          "start": 21,
+          "end": 30,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 21
+            },
+            "end": {
+              "line": 1,
+              "column": 30
+            }
+          },
+          "name": {
+            "type": "Identifier",
+            "start": 23,
+            "end": 28,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 23
+              },
+              "end": {
+                "line": 1,
+                "column": 28
+              },
+              "identifierName": "SUPER"
+            },
+            "name": "SUPER"
+          },
+          "expectedNode": "Expression"
+        },
+        "body": {
+          "type": "Placeholder",
+          "start": 31,
+          "end": 39,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 31
+            },
+            "end": {
+              "line": 1,
+              "column": 39
+            }
+          },
+          "name": {
+            "type": "Identifier",
+            "start": 33,
+            "end": 37,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 33
+              },
+              "end": {
+                "line": 1,
+                "column": 37
+              },
+              "identifierName": "BODY"
+            },
+            "name": "BODY"
+          },
+          "expectedNode": "ClassBody"
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/class/id-super/input.js

@@ -0,0 +1 @@
+class %%ID%% extends %%SUPER%% {}

packages/babel-parser/test/fixtures/placeholders/class/id-super/output.json

@@ -0,0 +1,132 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 33,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 33
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 33,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 33
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start": 0,
+        "end": 33,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 33
+          }
+        },
+        "id": {
+          "type": "Placeholder",
+          "start": 6,
+          "end": 12,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 6
+            },
+            "end": {
+              "line": 1,
+              "column": 12
+            }
+          },
+          "name": {
+            "type": "Identifier",
+            "start": 8,
+            "end": 10,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 8
+              },
+              "end": {
+                "line": 1,
+                "column": 10
+              },
+              "identifierName": "ID"
+            },
+            "name": "ID"
+          },
+          "expectedNode": "Identifier"
+        },
+        "superClass": {
+          "type": "Placeholder",
+          "start": 21,
+          "end": 30,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 21
+            },
+            "end": {
+              "line": 1,
+              "column": 30
+            }
+          },
+          "name": {
+            "type": "Identifier",
+            "start": 23,
+            "end": 28,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 23
+              },
+              "end": {
+                "line": 1,
+                "column": 28
+              },
+              "identifierName": "SUPER"
+            },
+            "name": "SUPER"
+          },
+          "expectedNode": "Expression"
+        },
+        "body": {
+          "type": "ClassBody",
+          "start": 31,
+          "end": 33,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 31
+            },
+            "end": {
+              "line": 1,
+              "column": 33
+            }
+          },
+          "body": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/class/id_expression/input.js

@@ -0,0 +1 @@
+void class %%ID%% {}

packages/babel-parser/test/fixtures/placeholders/class/id_expression/output.json

@@ -0,0 +1,132 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 20,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 20
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 20,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 20
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start": 0,
+        "end": 20,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 20
+          }
+        },
+        "expression": {
+          "type": "UnaryExpression",
+          "start": 0,
+          "end": 20,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 0
+            },
+            "end": {
+              "line": 1,
+              "column": 20
+            }
+          },
+          "operator": "void",
+          "prefix": true,
+          "argument": {
+            "type": "ClassExpression",
+            "start": 5,
+            "end": 20,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 5
+              },
+              "end": {
+                "line": 1,
+                "column": 20
+              }
+            },
+            "id": {
+              "type": "Placeholder",
+              "start": 11,
+              "end": 17,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 11
+                },
+                "end": {
+                  "line": 1,
+                  "column": 17
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 13,
+                "end": 15,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 13
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 15
+                  },
+                  "identifierName": "ID"
+                },
+                "name": "ID"
+              },
+              "expectedNode": "Identifier"
+            },
+            "superClass": null,
+            "body": {
+              "type": "ClassBody",
+              "start": 18,
+              "end": 20,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 18
+                },
+                "end": {
+                  "line": 1,
+                  "column": 20
+                }
+              },
+              "body": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/class/id_statement/input.js

@@ -0,0 +1 @@
+class %%ID%% {}

packages/babel-parser/test/fixtures/placeholders/class/id_statement/output.json

@@ -0,0 +1,100 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 15,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 15
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 15,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 15
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start": 0,
+        "end": 15,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 15
+          }
+        },
+        "id": {
+          "type": "Placeholder",
+          "start": 6,
+          "end": 12,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 6
+            },
+            "end": {
+              "line": 1,
+              "column": 12
+            }
+          },
+          "name": {
+            "type": "Identifier",
+            "start": 8,
+            "end": 10,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 8
+              },
+              "end": {
+                "line": 1,
+                "column": 10
+              },
+              "identifierName": "ID"
+            },
+            "name": "ID"
+          },
+          "expectedNode": "Identifier"
+        },
+        "superClass": null,
+        "body": {
+          "type": "ClassBody",
+          "start": 13,
+          "end": 15,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 13
+            },
+            "end": {
+              "line": 1,
+              "column": 15
+            }
+          },
+          "body": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/class/super/input.js

@@ -0,0 +1 @@
+class Cl extends %%SUPER%% {}

packages/babel-parser/test/fixtures/placeholders/class/super/output.json

@@ -0,0 +1,116 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 29,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 29
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 29,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 29
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start": 0,
+        "end": 29,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 29
+          }
+        },
+        "id": {
+          "type": "Identifier",
+          "start": 6,
+          "end": 8,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 6
+            },
+            "end": {
+              "line": 1,
+              "column": 8
+            },
+            "identifierName": "Cl"
+          },
+          "name": "Cl"
+        },
+        "superClass": {
+          "type": "Placeholder",
+          "start": 17,
+          "end": 26,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 17
+            },
+            "end": {
+              "line": 1,
+              "column": 26
+            }
+          },
+          "name": {
+            "type": "Identifier",
+            "start": 19,
+            "end": 24,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 19
+              },
+              "end": {
+                "line": 1,
+                "column": 24
+              },
+              "identifierName": "SUPER"
+            },
+            "name": "SUPER"
+          },
+          "expectedNode": "Expression"
+        },
+        "body": {
+          "type": "ClassBody",
+          "start": 27,
+          "end": 29,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 27
+            },
+            "end": {
+              "line": 1,
+              "column": 29
+            }
+          },
+          "body": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/export/declaration/input.js

@@ -0,0 +1 @@
+export %%DECL%%;

packages/babel-parser/test/fixtures/placeholders/export/declaration/output.json

@@ -0,0 +1,100 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 16,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 16
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 16,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 16
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 0,
+        "end": 15,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 15
+          }
+        },
+        "specifiers": [],
+        "source": null,
+        "declaration": {
+          "type": "Placeholder",
+          "start": 7,
+          "end": 15,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 7
+            },
+            "end": {
+              "line": 1,
+              "column": 15
+            }
+          },
+          "name": {
+            "type": "Identifier",
+            "start": 9,
+            "end": 13,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 9
+              },
+              "end": {
+                "line": 1,
+                "column": 13
+              },
+              "identifierName": "DECL"
+            },
+            "name": "DECL"
+          },
+          "expectedNode": "Declaration"
+        }
+      },
+      {
+        "type": "EmptyStatement",
+        "start": 15,
+        "end": 16,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 15
+          },
+          "end": {
+            "line": 1,
+            "column": 16
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/export/default-default-from/input.js

@@ -0,0 +1 @@
+export default from %%FILE%%;

packages/babel-parser/test/fixtures/placeholders/export/default-default-from/options.json

@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    "placeholders"
+  ],
+  "sourceType": "module",
+  "throws": "This experimental syntax requires enabling the parser plugin: 'exportDefaultFrom' (1:7)"
+}

packages/babel-parser/test/fixtures/placeholders/export/default-named-from-2/input.js

@@ -0,0 +1 @@
+export %%NAME%% from "file";

packages/babel-parser/test/fixtures/placeholders/export/default-named-from-2/options.json

@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    "placeholders"
+  ],
+  "sourceType": "module",
+  "throws": "This experimental syntax requires enabling the parser plugin: 'exportDefaultFrom' (1:16)"
+}

packages/babel-parser/test/fixtures/placeholders/export/default-named-from-3/input.js

@@ -0,0 +1 @@
+export %%NAME%% from %%FILE%%;

packages/babel-parser/test/fixtures/placeholders/export/default-named-from-3/options.json

@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    "placeholders"
+  ],
+  "sourceType": "module",
+  "throws": "This experimental syntax requires enabling the parser plugin: 'exportDefaultFrom' (1:16)"
+}

packages/babel-parser/test/fixtures/placeholders/export/default-named-from/input.js

@@ -0,0 +1 @@
+export name from %%FILE%%;

packages/babel-parser/test/fixtures/placeholders/export/default-named-from/options.json

@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    "placeholders"
+  ],
+  "sourceType": "module",
+  "throws": "This experimental syntax requires enabling the parser plugin: 'exportDefaultFrom' (1:7)"
+}

packages/babel-parser/test/fixtures/placeholders/export/named-alias-2/input.js

@@ -0,0 +1 @@
+export { name as %%ALIAS%% };

packages/babel-parser/test/fixtures/placeholders/export/named-alias-2/output.json

@@ -0,0 +1,119 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 29,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 29
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 29,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 29
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 0,
+        "end": 29,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 29
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ExportSpecifier",
+            "start": 9,
+            "end": 26,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 9
+              },
+              "end": {
+                "line": 1,
+                "column": 26
+              }
+            },
+            "local": {
+              "type": "Identifier",
+              "start": 9,
+              "end": 13,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 13
+                },
+                "identifierName": "name"
+              },
+              "name": "name"
+            },
+            "exported": {
+              "type": "Placeholder",
+              "start": 17,
+              "end": 26,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 17
+                },
+                "end": {
+                  "line": 1,
+                  "column": 26
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 19,
+                "end": 24,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 19
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 24
+                  },
+                  "identifierName": "ALIAS"
+                },
+                "name": "ALIAS"
+              },
+              "expectedNode": "Identifier"
+            }
+          }
+        ],
+        "source": null,
+        "declaration": null
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/export/named-alias-3/input.js

@@ -0,0 +1 @@
+export { %%NAME%% as %%ALIAS%% };

packages/babel-parser/test/fixtures/placeholders/export/named-alias-3/output.json

@@ -0,0 +1,135 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 33,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 33
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 33,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 33
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 0,
+        "end": 33,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 33
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ExportSpecifier",
+            "start": 9,
+            "end": 30,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 9
+              },
+              "end": {
+                "line": 1,
+                "column": 30
+              }
+            },
+            "local": {
+              "type": "Placeholder",
+              "start": 9,
+              "end": 17,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 17
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 11,
+                "end": 15,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 11
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 15
+                  },
+                  "identifierName": "NAME"
+                },
+                "name": "NAME"
+              },
+              "expectedNode": "Identifier"
+            },
+            "exported": {
+              "type": "Placeholder",
+              "start": 21,
+              "end": 30,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 21
+                },
+                "end": {
+                  "line": 1,
+                  "column": 30
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 23,
+                "end": 28,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 23
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 28
+                  },
+                  "identifierName": "ALIAS"
+                },
+                "name": "ALIAS"
+              },
+              "expectedNode": "Identifier"
+            }
+          }
+        ],
+        "source": null,
+        "declaration": null
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/export/named-alias/input.js

@@ -0,0 +1 @@
+export { %%NAME%% as alias };

packages/babel-parser/test/fixtures/placeholders/export/named-alias/output.json

@@ -0,0 +1,119 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 29,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 29
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 29,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 29
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 0,
+        "end": 29,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 29
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ExportSpecifier",
+            "start": 9,
+            "end": 26,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 9
+              },
+              "end": {
+                "line": 1,
+                "column": 26
+              }
+            },
+            "local": {
+              "type": "Placeholder",
+              "start": 9,
+              "end": 17,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 17
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 11,
+                "end": 15,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 11
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 15
+                  },
+                  "identifierName": "NAME"
+                },
+                "name": "NAME"
+              },
+              "expectedNode": "Identifier"
+            },
+            "exported": {
+              "type": "Identifier",
+              "start": 21,
+              "end": 26,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 21
+                },
+                "end": {
+                  "line": 1,
+                  "column": 26
+                },
+                "identifierName": "alias"
+              },
+              "name": "alias"
+            }
+          }
+        ],
+        "source": null,
+        "declaration": null
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/export/named-from-2/input.js

@@ -0,0 +1 @@
+export { name } from %%FILE%%;

packages/babel-parser/test/fixtures/placeholders/export/named-from-2/output.json

@@ -0,0 +1,135 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 30,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 30
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 30,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 30
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 0,
+        "end": 30,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 30
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ExportSpecifier",
+            "start": 9,
+            "end": 13,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 9
+              },
+              "end": {
+                "line": 1,
+                "column": 13
+              }
+            },
+            "local": {
+              "type": "Identifier",
+              "start": 9,
+              "end": 13,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 13
+                },
+                "identifierName": "name"
+              },
+              "name": "name"
+            },
+            "exported": {
+              "type": "Identifier",
+              "start": 9,
+              "end": 13,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 13
+                },
+                "identifierName": "name"
+              },
+              "name": "name"
+            }
+          }
+        ],
+        "source": {
+          "type": "Placeholder",
+          "start": 21,
+          "end": 29,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 21
+            },
+            "end": {
+              "line": 1,
+              "column": 29
+            }
+          },
+          "name": {
+            "type": "Identifier",
+            "start": 23,
+            "end": 27,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 23
+              },
+              "end": {
+                "line": 1,
+                "column": 27
+              },
+              "identifierName": "FILE"
+            },
+            "name": "FILE"
+          },
+          "expectedNode": "StringLiteral"
+        },
+        "declaration": null
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/export/named-from-3/input.js

@@ -0,0 +1 @@
+export { %%NAME%% } from %%FILE%%;

packages/babel-parser/test/fixtures/placeholders/export/named-from-3/output.json

@@ -0,0 +1,167 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 34,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 34
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 34,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 34
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 0,
+        "end": 34,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 34
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ExportSpecifier",
+            "start": 9,
+            "end": 17,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 9
+              },
+              "end": {
+                "line": 1,
+                "column": 17
+              }
+            },
+            "local": {
+              "type": "Placeholder",
+              "start": 9,
+              "end": 17,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 17
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 11,
+                "end": 15,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 11
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 15
+                  },
+                  "identifierName": "NAME"
+                },
+                "name": "NAME"
+              },
+              "expectedNode": "Identifier"
+            },
+            "exported": {
+              "type": "Placeholder",
+              "start": 9,
+              "end": 17,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 17
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 11,
+                "end": 15,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 11
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 15
+                  },
+                  "identifierName": "NAME"
+                },
+                "name": "NAME"
+              },
+              "expectedNode": "Identifier"
+            }
+          }
+        ],
+        "source": {
+          "type": "Placeholder",
+          "start": 25,
+          "end": 33,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 25
+            },
+            "end": {
+              "line": 1,
+              "column": 33
+            }
+          },
+          "name": {
+            "type": "Identifier",
+            "start": 27,
+            "end": 31,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 27
+              },
+              "end": {
+                "line": 1,
+                "column": 31
+              },
+              "identifierName": "FILE"
+            },
+            "name": "FILE"
+          },
+          "expectedNode": "StringLiteral"
+        },
+        "declaration": null
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/export/named-from-alias-2/input.js

@@ -0,0 +1 @@
+export { name as %%ALIAS%% } from "file";

packages/babel-parser/test/fixtures/placeholders/export/named-from-alias-2/output.json

@@ -0,0 +1,138 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 41,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 41
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 41,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 41
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 0,
+        "end": 41,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 41
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ExportSpecifier",
+            "start": 9,
+            "end": 26,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 9
+              },
+              "end": {
+                "line": 1,
+                "column": 26
+              }
+            },
+            "local": {
+              "type": "Identifier",
+              "start": 9,
+              "end": 13,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 13
+                },
+                "identifierName": "name"
+              },
+              "name": "name"
+            },
+            "exported": {
+              "type": "Placeholder",
+              "start": 17,
+              "end": 26,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 17
+                },
+                "end": {
+                  "line": 1,
+                  "column": 26
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 19,
+                "end": 24,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 19
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 24
+                  },
+                  "identifierName": "ALIAS"
+                },
+                "name": "ALIAS"
+              },
+              "expectedNode": "Identifier"
+            }
+          }
+        ],
+        "source": {
+          "type": "StringLiteral",
+          "start": 34,
+          "end": 40,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 34
+            },
+            "end": {
+              "line": 1,
+              "column": 40
+            }
+          },
+          "extra": {
+            "rawValue": "file",
+            "raw": "\"file\""
+          },
+          "value": "file"
+        },
+        "declaration": null
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/export/named-from-alias-3/input.js

@@ -0,0 +1 @@
+export { %%NAME%% as %%ALIAS%% } from "file";

packages/babel-parser/test/fixtures/placeholders/export/named-from-alias-3/output.json

@@ -0,0 +1,154 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 45,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 45
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 45,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 45
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 0,
+        "end": 45,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 45
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ExportSpecifier",
+            "start": 9,
+            "end": 30,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 9
+              },
+              "end": {
+                "line": 1,
+                "column": 30
+              }
+            },
+            "local": {
+              "type": "Placeholder",
+              "start": 9,
+              "end": 17,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 17
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 11,
+                "end": 15,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 11
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 15
+                  },
+                  "identifierName": "NAME"
+                },
+                "name": "NAME"
+              },
+              "expectedNode": "Identifier"
+            },
+            "exported": {
+              "type": "Placeholder",
+              "start": 21,
+              "end": 30,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 21
+                },
+                "end": {
+                  "line": 1,
+                  "column": 30
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 23,
+                "end": 28,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 23
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 28
+                  },
+                  "identifierName": "ALIAS"
+                },
+                "name": "ALIAS"
+              },
+              "expectedNode": "Identifier"
+            }
+          }
+        ],
+        "source": {
+          "type": "StringLiteral",
+          "start": 38,
+          "end": 44,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 38
+            },
+            "end": {
+              "line": 1,
+              "column": 44
+            }
+          },
+          "extra": {
+            "rawValue": "file",
+            "raw": "\"file\""
+          },
+          "value": "file"
+        },
+        "declaration": null
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/export/named-from-alias/input.js

@@ -0,0 +1 @@
+export { %%NAME%% as alias } from "file";

packages/babel-parser/test/fixtures/placeholders/export/named-from-alias/output.json

@@ -0,0 +1,138 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 41,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 41
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 41,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 41
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 0,
+        "end": 41,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 41
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ExportSpecifier",
+            "start": 9,
+            "end": 26,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 9
+              },
+              "end": {
+                "line": 1,
+                "column": 26
+              }
+            },
+            "local": {
+              "type": "Placeholder",
+              "start": 9,
+              "end": 17,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 17
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 11,
+                "end": 15,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 11
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 15
+                  },
+                  "identifierName": "NAME"
+                },
+                "name": "NAME"
+              },
+              "expectedNode": "Identifier"
+            },
+            "exported": {
+              "type": "Identifier",
+              "start": 21,
+              "end": 26,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 21
+                },
+                "end": {
+                  "line": 1,
+                  "column": 26
+                },
+                "identifierName": "alias"
+              },
+              "name": "alias"
+            }
+          }
+        ],
+        "source": {
+          "type": "StringLiteral",
+          "start": 34,
+          "end": 40,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 34
+            },
+            "end": {
+              "line": 1,
+              "column": 40
+            }
+          },
+          "extra": {
+            "rawValue": "file",
+            "raw": "\"file\""
+          },
+          "value": "file"
+        },
+        "declaration": null
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/export/named-from/input.js

@@ -0,0 +1 @@
+export { %%NAME%% } from "file";

packages/babel-parser/test/fixtures/placeholders/export/named-from/output.json

@@ -0,0 +1,154 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 32,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 32
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 32,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 32
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 0,
+        "end": 32,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 32
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ExportSpecifier",
+            "start": 9,
+            "end": 17,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 9
+              },
+              "end": {
+                "line": 1,
+                "column": 17
+              }
+            },
+            "local": {
+              "type": "Placeholder",
+              "start": 9,
+              "end": 17,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 17
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 11,
+                "end": 15,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 11
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 15
+                  },
+                  "identifierName": "NAME"
+                },
+                "name": "NAME"
+              },
+              "expectedNode": "Identifier"
+            },
+            "exported": {
+              "type": "Placeholder",
+              "start": 9,
+              "end": 17,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 17
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 11,
+                "end": 15,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 11
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 15
+                  },
+                  "identifierName": "NAME"
+                },
+                "name": "NAME"
+              },
+              "expectedNode": "Identifier"
+            }
+          }
+        ],
+        "source": {
+          "type": "StringLiteral",
+          "start": 25,
+          "end": 31,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 25
+            },
+            "end": {
+              "line": 1,
+              "column": 31
+            }
+          },
+          "extra": {
+            "rawValue": "file",
+            "raw": "\"file\""
+          },
+          "value": "file"
+        },
+        "declaration": null
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/export/named/input.js

@@ -0,0 +1 @@
+export { %%NAME%% };

packages/babel-parser/test/fixtures/placeholders/export/named/output.json

@@ -0,0 +1,135 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 20,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 20
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 20,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 20
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 0,
+        "end": 20,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 20
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ExportSpecifier",
+            "start": 9,
+            "end": 17,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 9
+              },
+              "end": {
+                "line": 1,
+                "column": 17
+              }
+            },
+            "local": {
+              "type": "Placeholder",
+              "start": 9,
+              "end": 17,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 17
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 11,
+                "end": 15,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 11
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 15
+                  },
+                  "identifierName": "NAME"
+                },
+                "name": "NAME"
+              },
+              "expectedNode": "Identifier"
+            },
+            "exported": {
+              "type": "Placeholder",
+              "start": 9,
+              "end": 17,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 9
+                },
+                "end": {
+                  "line": 1,
+                  "column": 17
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 11,
+                "end": 15,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 11
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 15
+                  },
+                  "identifierName": "NAME"
+                },
+                "name": "NAME"
+              },
+              "expectedNode": "Identifier"
+            }
+          }
+        ],
+        "source": null,
+        "declaration": null
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/export/options.json

@@ -0,0 +1,4 @@
+{
+  "plugins": ["placeholders", "exportDefaultFrom", "exportNamespaceFrom"],
+  "sourceType": "module"
+}

packages/babel-parser/test/fixtures/placeholders/export/star-from-2/input.js

@@ -0,0 +1 @@
+export * as %%STAR%% from "file";

packages/babel-parser/test/fixtures/placeholders/export/star-from-2/options.json

@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    "placeholders"
+  ],
+  "sourceType": "module",
+  "throws": "This experimental syntax requires enabling the parser plugin: 'exportNamespaceFrom' (1:9)"
+}

packages/babel-parser/test/fixtures/placeholders/export/star-from-3/input.js

@@ -0,0 +1 @@
+export * as %%STAR%% from %%FILE%%;

packages/babel-parser/test/fixtures/placeholders/export/star-from-3/options.json

@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    "placeholders"
+  ],
+  "sourceType": "module",
+  "throws": "This experimental syntax requires enabling the parser plugin: 'exportNamespaceFrom' (1:9)"
+}

packages/babel-parser/test/fixtures/placeholders/export/star-from/input.js

@@ -0,0 +1 @@
+export * from %%FILE%%;

packages/babel-parser/test/fixtures/placeholders/export/star-from/output.json

@@ -0,0 +1,83 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 23,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 23
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 23,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 23
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExportAllDeclaration",
+        "start": 0,
+        "end": 23,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 23
+          }
+        },
+        "source": {
+          "type": "Placeholder",
+          "start": 14,
+          "end": 22,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 14
+            },
+            "end": {
+              "line": 1,
+              "column": 22
+            }
+          },
+          "name": {
+            "type": "Identifier",
+            "start": 16,
+            "end": 20,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 16
+              },
+              "end": {
+                "line": 1,
+                "column": 20
+              },
+              "identifierName": "FILE"
+            },
+            "name": "FILE"
+          },
+          "expectedNode": "StringLiteral"
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/expression/01/input.js

@@ -0,0 +1 @@
+%%FOO%% + %%BAR%%(%%BAZ%%);

packages/babel-parser/test/fixtures/placeholders/expression/01/output.json

@@ -0,0 +1,182 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 27,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 27
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 27,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 27
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start": 0,
+        "end": 27,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 27
+          }
+        },
+        "expression": {
+          "type": "BinaryExpression",
+          "start": 0,
+          "end": 26,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 0
+            },
+            "end": {
+              "line": 1,
+              "column": 26
+            }
+          },
+          "left": {
+            "type": "Placeholder",
+            "start": 0,
+            "end": 7,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 0
+              },
+              "end": {
+                "line": 1,
+                "column": 7
+              }
+            },
+            "name": {
+              "type": "Identifier",
+              "start": 2,
+              "end": 5,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 2
+                },
+                "end": {
+                  "line": 1,
+                  "column": 5
+                },
+                "identifierName": "FOO"
+              },
+              "name": "FOO"
+            },
+            "expectedNode": "Expression"
+          },
+          "operator": "+",
+          "right": {
+            "type": "CallExpression",
+            "start": 10,
+            "end": 26,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 10
+              },
+              "end": {
+                "line": 1,
+                "column": 26
+              }
+            },
+            "callee": {
+              "type": "Placeholder",
+              "start": 10,
+              "end": 17,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 10
+                },
+                "end": {
+                  "line": 1,
+                  "column": 17
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 12,
+                "end": 15,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 12
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 15
+                  },
+                  "identifierName": "BAR"
+                },
+                "name": "BAR"
+              },
+              "expectedNode": "Expression"
+            },
+            "arguments": [
+              {
+                "type": "Placeholder",
+                "start": 18,
+                "end": 25,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 18
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 25
+                  }
+                },
+                "name": {
+                  "type": "Identifier",
+                  "start": 20,
+                  "end": 23,
+                  "loc": {
+                    "start": {
+                      "line": 1,
+                      "column": 20
+                    },
+                    "end": {
+                      "line": 1,
+                      "column": 23
+                    },
+                    "identifierName": "BAZ"
+                  },
+                  "name": "BAZ"
+                },
+                "expectedNode": "Expression"
+              }
+            ]
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/expression/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["placeholders"]
+}

packages/babel-parser/test/fixtures/placeholders/function/body/input.js

@@ -0,0 +1 @@
+function f() %%BODY%%

packages/babel-parser/test/fixtures/placeholders/function/body/output.json

@@ -0,0 +1,103 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 21,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 21
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 21,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 21
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start": 0,
+        "end": 21,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 21
+          }
+        },
+        "id": {
+          "type": "Identifier",
+          "start": 9,
+          "end": 10,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 9
+            },
+            "end": {
+              "line": 1,
+              "column": 10
+            },
+            "identifierName": "f"
+          },
+          "name": "f"
+        },
+        "generator": false,
+        "async": false,
+        "params": [],
+        "body": {
+          "type": "Placeholder",
+          "start": 13,
+          "end": 21,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 13
+            },
+            "end": {
+              "line": 1,
+              "column": 21
+            }
+          },
+          "name": {
+            "type": "Identifier",
+            "start": 15,
+            "end": 19,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 15
+              },
+              "end": {
+                "line": 1,
+                "column": 19
+              },
+              "identifierName": "BODY"
+            },
+            "name": "BODY"
+          },
+          "expectedNode": "BlockStatement"
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/function/id-params-body/input.js

@@ -0,0 +1 @@
+function %%ID%%(%%PARAM%%, %%PARAM%%) %%BODY%%

packages/babel-parser/test/fixtures/placeholders/function/id-params-body/output.json

@@ -0,0 +1,186 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 46,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 46
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 46,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 46
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start": 0,
+        "end": 46,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 46
+          }
+        },
+        "id": {
+          "type": "Placeholder",
+          "start": 9,
+          "end": 15,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 9
+            },
+            "end": {
+              "line": 1,
+              "column": 15
+            }
+          },
+          "name": {
+            "type": "Identifier",
+            "start": 11,
+            "end": 13,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 11
+              },
+              "end": {
+                "line": 1,
+                "column": 13
+              },
+              "identifierName": "ID"
+            },
+            "name": "ID"
+          },
+          "expectedNode": "Identifier"
+        },
+        "generator": false,
+        "async": false,
+        "params": [
+          {
+            "type": "Placeholder",
+            "start": 16,
+            "end": 25,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 16
+              },
+              "end": {
+                "line": 1,
+                "column": 25
+              }
+            },
+            "name": {
+              "type": "Identifier",
+              "start": 18,
+              "end": 23,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 18
+                },
+                "end": {
+                  "line": 1,
+                  "column": 23
+                },
+                "identifierName": "PARAM"
+              },
+              "name": "PARAM"
+            },
+            "expectedNode": "Pattern"
+          },
+          {
+            "type": "Placeholder",
+            "start": 27,
+            "end": 36,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 27
+              },
+              "end": {
+                "line": 1,
+                "column": 36
+              }
+            },
+            "name": {
+              "type": "Identifier",
+              "start": 29,
+              "end": 34,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 29
+                },
+                "end": {
+                  "line": 1,
+                  "column": 34
+                },
+                "identifierName": "PARAM"
+              },
+              "name": "PARAM"
+            },
+            "expectedNode": "Pattern"
+          }
+        ],
+        "body": {
+          "type": "Placeholder",
+          "start": 38,
+          "end": 46,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 38
+            },
+            "end": {
+              "line": 1,
+              "column": 46
+            }
+          },
+          "name": {
+            "type": "Identifier",
+            "start": 40,
+            "end": 44,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 40
+              },
+              "end": {
+                "line": 1,
+                "column": 44
+              },
+              "identifierName": "BODY"
+            },
+            "name": "BODY"
+          },
+          "expectedNode": "BlockStatement"
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/function/id_declaration/input.js

@@ -0,0 +1 @@
+function %%ID%%() {}

packages/babel-parser/test/fixtures/placeholders/function/id_declaration/output.json

@@ -0,0 +1,103 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 20,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 20
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 20,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 20
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start": 0,
+        "end": 20,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 20
+          }
+        },
+        "id": {
+          "type": "Placeholder",
+          "start": 9,
+          "end": 15,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 9
+            },
+            "end": {
+              "line": 1,
+              "column": 15
+            }
+          },
+          "name": {
+            "type": "Identifier",
+            "start": 11,
+            "end": 13,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 11
+              },
+              "end": {
+                "line": 1,
+                "column": 13
+              },
+              "identifierName": "ID"
+            },
+            "name": "ID"
+          },
+          "expectedNode": "Identifier"
+        },
+        "generator": false,
+        "async": false,
+        "params": [],
+        "body": {
+          "type": "BlockStatement",
+          "start": 18,
+          "end": 20,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 18
+            },
+            "end": {
+              "line": 1,
+              "column": 20
+            }
+          },
+          "body": [],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/function/id_expression/input.js

@@ -0,0 +1 @@
+void function %%ID%%() {};

packages/babel-parser/test/fixtures/placeholders/function/id_expression/output.json

@@ -0,0 +1,135 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 26,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 26
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 26,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 26
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start": 0,
+        "end": 26,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 26
+          }
+        },
+        "expression": {
+          "type": "UnaryExpression",
+          "start": 0,
+          "end": 25,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 0
+            },
+            "end": {
+              "line": 1,
+              "column": 25
+            }
+          },
+          "operator": "void",
+          "prefix": true,
+          "argument": {
+            "type": "FunctionExpression",
+            "start": 5,
+            "end": 25,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 5
+              },
+              "end": {
+                "line": 1,
+                "column": 25
+              }
+            },
+            "id": {
+              "type": "Placeholder",
+              "start": 14,
+              "end": 20,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 14
+                },
+                "end": {
+                  "line": 1,
+                  "column": 20
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 16,
+                "end": 18,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 16
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 18
+                  },
+                  "identifierName": "ID"
+                },
+                "name": "ID"
+              },
+              "expectedNode": "Identifier"
+            },
+            "generator": false,
+            "async": false,
+            "params": [],
+            "body": {
+              "type": "BlockStatement",
+              "start": 23,
+              "end": 25,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 23
+                },
+                "end": {
+                  "line": 1,
+                  "column": 25
+                }
+              },
+              "body": [],
+              "directives": []
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/function/param/input.js

@@ -0,0 +1 @@
+function f(%%PARAM%%) {}

packages/babel-parser/test/fixtures/placeholders/function/param/output.json

@@ -0,0 +1,121 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 24,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 24
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 24,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 24
+      }
+    },
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start": 0,
+        "end": 24,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 24
+          }
+        },
+        "id": {
+          "type": "Identifier",
+          "start": 9,
+          "end": 10,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 9
+            },
+            "end": {
+              "line": 1,
+              "column": 10
+            },
+            "identifierName": "f"
+          },
+          "name": "f"
+        },
+        "generator": false,
+        "async": false,
+        "params": [
+          {
+            "type": "Placeholder",
+            "start": 11,
+            "end": 20,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 11
+              },
+              "end": {
+                "line": 1,
+                "column": 20
+              }
+            },
+            "name": {
+              "type": "Identifier",
+              "start": 13,
+              "end": 18,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 13
+                },
+                "end": {
+                  "line": 1,
+                  "column": 18
+                },
+                "identifierName": "PARAM"
+              },
+              "name": "PARAM"
+            },
+            "expectedNode": "Pattern"
+          }
+        ],
+        "body": {
+          "type": "BlockStatement",
+          "start": 22,
+          "end": 24,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 22
+            },
+            "end": {
+              "line": 1,
+              "column": 24
+            }
+          },
+          "body": [],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/import/default-file/input.mjs

@@ -0,0 +1 @@
+import %%DEFAULT%% from %%FILE%%;

packages/babel-parser/test/fixtures/placeholders/import/default-file/output.json

@@ -0,0 +1,133 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 33,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 33
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 33,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 33
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ImportDeclaration",
+        "start": 0,
+        "end": 33,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 33
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ImportDefaultSpecifier",
+            "start": 7,
+            "end": 18,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 7
+              },
+              "end": {
+                "line": 1,
+                "column": 18
+              }
+            },
+            "local": {
+              "type": "Placeholder",
+              "start": 7,
+              "end": 18,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 7
+                },
+                "end": {
+                  "line": 1,
+                  "column": 18
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 9,
+                "end": 16,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 9
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 16
+                  },
+                  "identifierName": "DEFAULT"
+                },
+                "name": "DEFAULT"
+              },
+              "expectedNode": "Identifier"
+            }
+          }
+        ],
+        "source": {
+          "type": "Placeholder",
+          "start": 24,
+          "end": 32,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 24
+            },
+            "end": {
+              "line": 1,
+              "column": 32
+            }
+          },
+          "name": {
+            "type": "Identifier",
+            "start": 26,
+            "end": 30,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 26
+              },
+              "end": {
+                "line": 1,
+                "column": 30
+              },
+              "identifierName": "FILE"
+            },
+            "name": "FILE"
+          },
+          "expectedNode": "StringLiteral"
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/import/default-named-2/input.mjs

@@ -0,0 +1 @@
+import %%DEFAULT%%, { named } from "file";

packages/babel-parser/test/fixtures/placeholders/import/default-named-2/output.json

@@ -0,0 +1,169 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 42,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 42
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 42,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 42
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ImportDeclaration",
+        "start": 0,
+        "end": 42,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 42
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ImportDefaultSpecifier",
+            "start": 7,
+            "end": 18,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 7
+              },
+              "end": {
+                "line": 1,
+                "column": 18
+              }
+            },
+            "local": {
+              "type": "Placeholder",
+              "start": 7,
+              "end": 18,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 7
+                },
+                "end": {
+                  "line": 1,
+                  "column": 18
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 9,
+                "end": 16,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 9
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 16
+                  },
+                  "identifierName": "DEFAULT"
+                },
+                "name": "DEFAULT"
+              },
+              "expectedNode": "Identifier"
+            }
+          },
+          {
+            "type": "ImportSpecifier",
+            "start": 22,
+            "end": 27,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 22
+              },
+              "end": {
+                "line": 1,
+                "column": 27
+              }
+            },
+            "imported": {
+              "type": "Identifier",
+              "start": 22,
+              "end": 27,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 22
+                },
+                "end": {
+                  "line": 1,
+                  "column": 27
+                },
+                "identifierName": "named"
+              },
+              "name": "named"
+            },
+            "local": {
+              "type": "Identifier",
+              "start": 22,
+              "end": 27,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 22
+                },
+                "end": {
+                  "line": 1,
+                  "column": 27
+                },
+                "identifierName": "named"
+              },
+              "name": "named"
+            }
+          }
+        ],
+        "source": {
+          "type": "StringLiteral",
+          "start": 35,
+          "end": 41,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 35
+            },
+            "end": {
+              "line": 1,
+              "column": 41
+            }
+          },
+          "extra": {
+            "rawValue": "file",
+            "raw": "\"file\""
+          },
+          "value": "file"
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/import/default-named-3/input.mjs

@@ -0,0 +1 @@
+import %%DEFAULT%%, { %%NAMED%% } from "file";

packages/babel-parser/test/fixtures/placeholders/import/default-named-3/output.json

@@ -0,0 +1,201 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 46,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 46
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 46,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 46
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ImportDeclaration",
+        "start": 0,
+        "end": 46,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 46
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ImportDefaultSpecifier",
+            "start": 7,
+            "end": 18,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 7
+              },
+              "end": {
+                "line": 1,
+                "column": 18
+              }
+            },
+            "local": {
+              "type": "Placeholder",
+              "start": 7,
+              "end": 18,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 7
+                },
+                "end": {
+                  "line": 1,
+                  "column": 18
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 9,
+                "end": 16,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 9
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 16
+                  },
+                  "identifierName": "DEFAULT"
+                },
+                "name": "DEFAULT"
+              },
+              "expectedNode": "Identifier"
+            }
+          },
+          {
+            "type": "ImportSpecifier",
+            "start": 22,
+            "end": 31,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 22
+              },
+              "end": {
+                "line": 1,
+                "column": 31
+              }
+            },
+            "imported": {
+              "type": "Placeholder",
+              "start": 22,
+              "end": 31,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 22
+                },
+                "end": {
+                  "line": 1,
+                  "column": 31
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 24,
+                "end": 29,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 24
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 29
+                  },
+                  "identifierName": "NAMED"
+                },
+                "name": "NAMED"
+              },
+              "expectedNode": "Identifier"
+            },
+            "local": {
+              "type": "Placeholder",
+              "start": 22,
+              "end": 31,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 22
+                },
+                "end": {
+                  "line": 1,
+                  "column": 31
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 24,
+                "end": 29,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 24
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 29
+                  },
+                  "identifierName": "NAMED"
+                },
+                "name": "NAMED"
+              },
+              "expectedNode": "Identifier"
+            }
+          }
+        ],
+        "source": {
+          "type": "StringLiteral",
+          "start": 39,
+          "end": 45,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 39
+            },
+            "end": {
+              "line": 1,
+              "column": 45
+            }
+          },
+          "extra": {
+            "rawValue": "file",
+            "raw": "\"file\""
+          },
+          "value": "file"
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/import/default-named/input.mjs

@@ -0,0 +1 @@
+import _default, { %%NAMED%% } from "file";

packages/babel-parser/test/fixtures/placeholders/import/default-named/output.json

@@ -0,0 +1,185 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 43,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 43
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 43,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 43
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ImportDeclaration",
+        "start": 0,
+        "end": 43,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 43
+          }
+        },
+        "specifiers": [
+          {
+            "type": "ImportDefaultSpecifier",
+            "start": 7,
+            "end": 15,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 7
+              },
+              "end": {
+                "line": 1,
+                "column": 15
+              }
+            },
+            "local": {
+              "type": "Identifier",
+              "start": 7,
+              "end": 15,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 7
+                },
+                "end": {
+                  "line": 1,
+                  "column": 15
+                },
+                "identifierName": "_default"
+              },
+              "name": "_default"
+            }
+          },
+          {
+            "type": "ImportSpecifier",
+            "start": 19,
+            "end": 28,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 19
+              },
+              "end": {
+                "line": 1,
+                "column": 28
+              }
+            },
+            "imported": {
+              "type": "Placeholder",
+              "start": 19,
+              "end": 28,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 19
+                },
+                "end": {
+                  "line": 1,
+                  "column": 28
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 21,
+                "end": 26,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 21
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 26
+                  },
+                  "identifierName": "NAMED"
+                },
+                "name": "NAMED"
+              },
+              "expectedNode": "Identifier"
+            },
+            "local": {
+              "type": "Placeholder",
+              "start": 19,
+              "end": 28,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 19
+                },
+                "end": {
+                  "line": 1,
+                  "column": 28
+                }
+              },
+              "name": {
+                "type": "Identifier",
+                "start": 21,
+                "end": 26,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 21
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 26
+                  },
+                  "identifierName": "NAMED"
+                },
+                "name": "NAMED"
+              },
+              "expectedNode": "Identifier"
+            }
+          }
+        ],
+        "source": {
+          "type": "StringLiteral",
+          "start": 36,
+          "end": 42,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 36
+            },
+            "end": {
+              "line": 1,
+              "column": 42
+            }
+          },
+          "extra": {
+            "rawValue": "file",
+            "raw": "\"file\""
+          },
+          "value": "file"
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/placeholders/import/default-star-2/input.mjs

@@ -0,0 +1 @@
+import _default, * as %%STAR%% from "file";