rewrite void-returning statements in constructors that capture result of super call

src/compiler/transformers/es2015.ts

@@ -186,6 +186,7 @@ namespace ts {
         let enclosingFunction: FunctionLikeDeclaration;
         let enclosingNonArrowFunction: FunctionLikeDeclaration;
         let enclosingNonAsyncFunctionBody: FunctionLikeDeclaration | ClassElement;
+        let isInConstructorWithCapturedSuper: boolean;
 
         /**
          * Used to track if we are emitting body of the converted loop
@@ -231,14 +232,17 @@ namespace ts {
             const savedCurrentParent = currentParent;
             const savedCurrentNode = currentNode;
             const savedConvertedLoopState = convertedLoopState;
+            const savedIsInConstructorWithCapturedSuper = isInConstructorWithCapturedSuper;
             if (nodeStartsNewLexicalEnvironment(node)) {
-                // don't treat content of nodes that start new lexical environment as part of converted loop copy
+                // don't treat content of nodes that start new lexical environment as part of converted loop copy or constructor body
+                isInConstructorWithCapturedSuper = false;
                 convertedLoopState = undefined;
             }
 
             onBeforeVisitNode(node);
             const visited = f(node);
 
+            isInConstructorWithCapturedSuper = savedIsInConstructorWithCapturedSuper;
             convertedLoopState = savedConvertedLoopState;
             enclosingFunction = savedEnclosingFunction;
             enclosingNonArrowFunction = savedEnclosingNonArrowFunction;
@@ -251,17 +255,31 @@ namespace ts {
             return visited;
         }
 
+        function returnCapturedThis(node: Node): Node {
+            return setOriginalNode(createReturn(createIdentifier("_this")), node);
+        }
+
+        function isReturnVoidStatementInConstructorWithCapturedSuper(node: Node): boolean {
+            return isInConstructorWithCapturedSuper && node.kind === SyntaxKind.ReturnStatement && !(<ReturnStatement>node).expression;
+        }
+
         function shouldCheckNode(node: Node): boolean {
             return (node.transformFlags & TransformFlags.ES2015) !== 0 ||
                 node.kind === SyntaxKind.LabeledStatement ||
                 (isIterationStatement(node, /*lookInLabeledStatements*/ false) && shouldConvertIterationStatementBody(node));
         }
 
         function visitorWorker(node: Node): VisitResult<Node> {
-            if (shouldCheckNode(node)) {
+            if (isReturnVoidStatementInConstructorWithCapturedSuper(node)) {
+                return returnCapturedThis(<ReturnStatement>node);
+            }
+            else if (shouldCheckNode(node)) {
                 return visitJavaScript(node);
             }
-            else if (node.transformFlags & TransformFlags.ContainsES2015) {
+            else if (node.transformFlags & TransformFlags.ContainsES2015 || (isInConstructorWithCapturedSuper && !isExpression(node))) {
+                // we want to dive in this branch either if node has children with ES2015 specific syntax
+                // or we are inside constructor that captures result of the super call so all returns without expression should be
+                // rewritten. Note: we skip expressions since returns should never appear there 
                 return visitEachChild(node, visitor, context);
             }
             else {
@@ -283,6 +301,7 @@ namespace ts {
         function visitNodesInConvertedLoop(node: Node): VisitResult<Node> {
             switch (node.kind) {
                 case SyntaxKind.ReturnStatement:
+                    node = isReturnVoidStatementInConstructorWithCapturedSuper(node) ? returnCapturedThis(node) : node;
                     return visitReturnStatement(<ReturnStatement>node);
 
                 case SyntaxKind.VariableStatement:
@@ -864,7 +883,10 @@ namespace ts {
             }
 
             if (constructor) {
-                const body = saveStateAndInvoke(constructor, constructor => visitNodes(constructor.body.statements, visitor, isStatement, /*start*/ statementOffset));
+                const body = saveStateAndInvoke(constructor, constructor => {
+                    isInConstructorWithCapturedSuper = superCaptureStatus === SuperCaptureResult.ReplaceSuperCapture;
+                    return visitNodes(constructor.body.statements, visitor, isStatement, /*start*/ statementOffset);
+                });
                 addRange(statements, body);
             }
 

tests/baselines/reference/constructorWithCapturedSuper.js

@@ -0,0 +1,123 @@
+//// [constructorWithCapturedSuper.ts]
+let oneA: A;
+
+class A {
+    constructor() {
+        return oneA;
+    }
+}
+
+class B extends A {
+    constructor(x: number) {
+        super();
+        if (x === 1) {
+            return;
+        }
+        while (x < 2) {
+            return;
+        }
+        try {
+            return
+        }
+        catch (e) {
+            return;
+        }
+        finally {
+            return;
+        }
+    }
+}
+
+class C extends A {
+    constructor(x: number) {
+        super();
+        for (let i = 0; i < 10; ++i) {
+            () => i + x;
+            if (x === 1) {
+                return;
+            } 
+        }
+    }
+}
+
+class D extends A {
+    constructor(x: number) {
+        super();
+        () => {
+            return;
+        }
+        function foo() {
+            return;
+        }
+    }
+}
+
+//// [constructorWithCapturedSuper.js]
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+var oneA;
+var A = (function () {
+    function A() {
+        return oneA;
+    }
+    return A;
+}());
+var B = (function (_super) {
+    __extends(B, _super);
+    function B(x) {
+        var _this = _super.call(this) || this;
+        if (x === 1) {
+            return _this;
+        }
+        while (x < 2) {
+            return _this;
+        }
+        try {
+            return _this;
+        }
+        catch (e) {
+            return _this;
+        }
+        finally {
+            return _this;
+        }
+        return _this;
+    }
+    return B;
+}(A));
+var C = (function (_super) {
+    __extends(C, _super);
+    function C(x) {
+        var _this = _super.call(this) || this;
+        var _loop_1 = function (i) {
+            (function () { return i + x; });
+            if (x === 1) {
+                return { value: _this };
+            }
+        };
+        for (var i = 0; i < 10; ++i) {
+            var state_1 = _loop_1(i);
+            if (typeof state_1 === "object")
+                return state_1.value;
+        }
+        return _this;
+    }
+    return C;
+}(A));
+var D = (function (_super) {
+    __extends(D, _super);
+    function D(x) {
+        var _this = _super.call(this) || this;
+        (function () {
+            return;
+        });
+        function foo() {
+            return;
+        }
+        return _this;
+    }
+    return D;
+}(A));

tests/baselines/reference/constructorWithCapturedSuper.symbols

@@ -0,0 +1,96 @@
+=== tests/cases/compiler/constructorWithCapturedSuper.ts ===
+let oneA: A;
+>oneA : Symbol(oneA, Decl(constructorWithCapturedSuper.ts, 0, 3))
+>A : Symbol(A, Decl(constructorWithCapturedSuper.ts, 0, 12))
+
+class A {
+>A : Symbol(A, Decl(constructorWithCapturedSuper.ts, 0, 12))
+
+    constructor() {
+        return oneA;
+>oneA : Symbol(oneA, Decl(constructorWithCapturedSuper.ts, 0, 3))
+    }
+}
+
+class B extends A {
+>B : Symbol(B, Decl(constructorWithCapturedSuper.ts, 6, 1))
+>A : Symbol(A, Decl(constructorWithCapturedSuper.ts, 0, 12))
+
+    constructor(x: number) {
+>x : Symbol(x, Decl(constructorWithCapturedSuper.ts, 9, 16))
+
+        super();
+>super : Symbol(A, Decl(constructorWithCapturedSuper.ts, 0, 12))
+
+        if (x === 1) {
+>x : Symbol(x, Decl(constructorWithCapturedSuper.ts, 9, 16))
+
+            return;
+        }
+        while (x < 2) {
+>x : Symbol(x, Decl(constructorWithCapturedSuper.ts, 9, 16))
+
+            return;
+        }
+        try {
+            return
+        }
+        catch (e) {
+>e : Symbol(e, Decl(constructorWithCapturedSuper.ts, 20, 15))
+
+            return;
+        }
+        finally {
+            return;
+        }
+    }
+}
+
+class C extends A {
+>C : Symbol(C, Decl(constructorWithCapturedSuper.ts, 27, 1))
+>A : Symbol(A, Decl(constructorWithCapturedSuper.ts, 0, 12))
+
+    constructor(x: number) {
+>x : Symbol(x, Decl(constructorWithCapturedSuper.ts, 30, 16))
+
+        super();
+>super : Symbol(A, Decl(constructorWithCapturedSuper.ts, 0, 12))
+
+        for (let i = 0; i < 10; ++i) {
+>i : Symbol(i, Decl(constructorWithCapturedSuper.ts, 32, 16))
+>i : Symbol(i, Decl(constructorWithCapturedSuper.ts, 32, 16))
+>i : Symbol(i, Decl(constructorWithCapturedSuper.ts, 32, 16))
+
+            () => i + x;
+>i : Symbol(i, Decl(constructorWithCapturedSuper.ts, 32, 16))
+>x : Symbol(x, Decl(constructorWithCapturedSuper.ts, 30, 16))
+
+            if (x === 1) {
+>x : Symbol(x, Decl(constructorWithCapturedSuper.ts, 30, 16))
+
+                return;
+            } 
+        }
+    }
+}
+
+class D extends A {
+>D : Symbol(D, Decl(constructorWithCapturedSuper.ts, 39, 1))
+>A : Symbol(A, Decl(constructorWithCapturedSuper.ts, 0, 12))
+
+    constructor(x: number) {
+>x : Symbol(x, Decl(constructorWithCapturedSuper.ts, 42, 16))
+
+        super();
+>super : Symbol(A, Decl(constructorWithCapturedSuper.ts, 0, 12))
+
+        () => {
+            return;
+        }
+        function foo() {
+>foo : Symbol(foo, Decl(constructorWithCapturedSuper.ts, 46, 9))
+
+            return;
+        }
+    }
+}