Don't replace the last statement if 'this' is used/captured within the constructor.

DanielRosenwasser · DanielRosenwasser · commit 7da4b857f2a0 · 2016-12-13T11:58:58.000-08:00
diff --git a/src/compiler/transformers/es2015.ts b/src/compiler/transformers/es2015.ts
@@ -1024,8 +1024,11 @@ namespace ts {
                 }
             }
 
-            // Return the result if we have an immediate super() call on the last statement.
-            if (superCallExpression && statementOffset === ctorStatements.length - 1) {
+            // Return the result if we have an immediate super() call on the last statement,
+            // but only if the constructor itself doesn't use 'this' elsewhere.
+            if (superCallExpression
+            && statementOffset === ctorStatements.length - 1
+            && !(ctor.transformFlags & (TransformFlags.ContainsLexicalThis | TransformFlags.ContainsCapturedLexicalThis))) {
                 const returnStatement = createReturn(superCallExpression);
 
                 if (superCallExpression.kind !== SyntaxKind.BinaryExpression

Original file line number	Diff line number	Diff line change
`@@ -1024,8 +1024,11 @@ namespace ts {`
`1024`	`1024`	`}`
`1025`	`1025`	`}`
`1026`	`1026`
`1027`		`- // Return the result if we have an immediate super() call on the last statement.`
`1028`		`- if (superCallExpression && statementOffset === ctorStatements.length - 1) {`
	`1027`	`+ // Return the result if we have an immediate super() call on the last statement,`
	`1028`	`+ // but only if the constructor itself doesn't use 'this' elsewhere.`
	`1029`	`+ if (superCallExpression`
	`1030`	`+ && statementOffset === ctorStatements.length - 1`
	`1031`	`+ && !(ctor.transformFlags & (TransformFlags.ContainsLexicalThis \| TransformFlags.ContainsCapturedLexicalThis))) {`
`1029`	`1032`	`const returnStatement = createReturn(superCallExpression);`
`1030`	`1033`
`1031`	`1034`	`if (superCallExpression.kind !== SyntaxKind.BinaryExpression`