fix: assure left bracket is not consumed after dot (#13695)

* fix: assure left bracket is not consumed after dot

* address review comments

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

@@ -701,6 +701,7 @@ export default class ExpressionParser extends LValParser {
     }
 
     let optional = false;
+
     if (this.match(tt.questionDot)) {
       if (noCalls && this.lookaheadCharCode() === charCodes.leftParenthesis) {
         // stop at `?.` when parsing `new a?.()`
@@ -719,13 +720,23 @@ export default class ExpressionParser extends LValParser {
         state,
         optional,
       );
-    } else if (optional || this.match(tt.bracketL) || this.eat(tt.dot)) {
-      return this.parseMember(base, startPos, startLoc, state, optional);
+    } else {
+      const computed = this.eat(tt.bracketL);
+      if (computed || optional || this.eat(tt.dot)) {
+        return this.parseMember(
+          base,
+          startPos,
+          startLoc,
+          state,
+          computed,
+          optional,
+        );
       } else {
         state.stop = true;
         return base;
       }
     }
+  }
 
   // base[?Yield, ?Await] [ Expression[+In, ?Yield, ?Await] ]
   // base[?Yield, ?Await] . IdentifierName
@@ -736,10 +747,10 @@ export default class ExpressionParser extends LValParser {
     startPos: number,
     startLoc: Position,
     state: N.ParseSubscriptState,
+    computed: boolean,
     optional: boolean,
   ): N.OptionalMemberExpression | N.MemberExpression {
     const node = this.startNodeAt(startPos, startLoc);
-    const computed = this.eat(tt.bracketL);
     node.object = base;
     node.computed = computed;
     const privateName =

packages/babel-parser/test/fixtures/core/regression/13694-invalid-dot-bracketL-member/input.js

@@ -0,0 +1 @@
+a.[b]

packages/babel-parser/test/fixtures/core/regression/13694-invalid-dot-bracketL-member/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "Unexpected token (1:2)"
+}