From 58768072effe299da7d121fa69e92ed579c3c9ad Mon Sep 17 00:00:00 2001
From: Daniel Tschinder <daniel@tschinder.de>
Date: Tue, 15 Jan 2019 23:32:18 -0800
Subject: [PATCH] perf: Ensure canInsertSemicolon is always called last

It does a lot of checks and a regex test
---
 packages/babel-parser/src/parser/expression.js | 11 ++++++-----
 packages/babel-parser/src/plugins/flow.js      |  2 +-
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/packages/babel-parser/src/parser/expression.js b/packages/babel-parser/src/parser/expression.js
index 7a485837b2..b65d057470 100644
--- a/packages/babel-parser/src/parser/expression.js
+++ b/packages/babel-parser/src/parser/expression.js
@@ -869,9 +869,9 @@ export default class ExpressionParser extends LValParser {
           return this.parseFunction(node, false, false, true);
         } else if (
           canBeArrow &&
-          !this.canInsertSemicolon() &&
           id.name === "async" &&
-          this.match(tt.name)
+          this.match(tt.name) &&
+          !this.canInsertSemicolon()
         ) {
           const oldYOAIPAP = this.state.yieldOrAwaitInPossibleArrowParameters;
           const oldInAsync = this.state.inAsync;
@@ -886,7 +886,8 @@ export default class ExpressionParser extends LValParser {
           return node;
         }
 
-        if (canBeArrow && !this.canInsertSemicolon() && this.eat(tt.arrow)) {
+        if (canBeArrow && this.match(tt.arrow) && !this.canInsertSemicolon()) {
+          this.next();
           const oldYOAIPAP = this.state.yieldOrAwaitInPossibleArrowParameters;
           this.state.yieldOrAwaitInPossibleArrowParameters = null;
           this.parseArrowExpression(node, [id]);
@@ -2076,8 +2077,8 @@ export default class ExpressionParser extends LValParser {
     this.next();
     if (
       this.match(tt.semi) ||
-      this.canInsertSemicolon() ||
-      (!this.match(tt.star) && !this.state.type.startsExpr)
+      (!this.match(tt.star) && !this.state.type.startsExpr) ||
+      this.canInsertSemicolon()
     ) {
       node.delegate = false;
       node.argument = null;
diff --git a/packages/babel-parser/src/plugins/flow.js b/packages/babel-parser/src/plugins/flow.js
index e0a729334a..878cc4c308 100644
--- a/packages/babel-parser/src/plugins/flow.js
+++ b/packages/babel-parser/src/plugins/flow.js
@@ -1398,7 +1398,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       const startPos = this.state.start,
         startLoc = this.state.startLoc;
       let type = this.flowParsePrimaryType();
-      while (!this.canInsertSemicolon() && this.match(tt.bracketL)) {
+      while (this.match(tt.bracketL) && !this.canInsertSemicolon()) {
         const node = this.startNodeAt(startPos, startLoc);
         node.elementType = type;
         this.expect(tt.bracketL);