lift multiple statements into block if necessary (#12965)

Author: vladima

src/compiler/transformers/es2015.ts

@@ -2290,7 +2290,7 @@ namespace ts {
             }
 
             startLexicalEnvironment();
-            let loopBody = visitNode(node.statement, visitor, isStatement);
+            let loopBody = visitNode(node.statement, visitor, isStatement, /*optional*/ false, liftToBlock);
             const lexicalEnvironment = endLexicalEnvironment();
 
             const currentState = convertedLoopState;
@@ -2305,7 +2305,10 @@ namespace ts {
                 loopBody = createBlock(statements, /*location*/ undefined, /*multiline*/ true);
             }
 
-            if (!isBlock(loopBody)) {
+            if (isBlock(loopBody)) {
+                loopBody.multiLine = true;
+            }
+            else {
                 loopBody = createBlock([loopBody], /*location*/ undefined, /*multiline*/ true);
             }
 

tests/baselines/reference/nestedLoops.js

@@ -0,0 +1,47 @@
+//// [nestedLoops.ts]
+export class Test  {
+    constructor() {
+
+        let outerArray: Array<number> = [1, 2, 3];
+        let innerArray: Array<number> = [1, 2, 3];
+
+        for (let outer of outerArray)
+            for (let inner of innerArray) {
+                this.aFunction((newValue, oldValue) => {
+                    let x = outer + inner + newValue;
+                });
+            }
+    }
+
+    public aFunction(func: (newValue: any, oldValue: any) => void): void {
+    }
+}
+
+//// [nestedLoops.js]
+"use strict";
+var Test = (function () {
+    function Test() {
+        var outerArray = [1, 2, 3];
+        var innerArray = [1, 2, 3];
+        var _loop_1 = function (outer) {
+            var _loop_2 = function (inner) {
+                this_1.aFunction(function (newValue, oldValue) {
+                    var x = outer + inner + newValue;
+                });
+            };
+            for (var _i = 0, innerArray_1 = innerArray; _i < innerArray_1.length; _i++) {
+                var inner = innerArray_1[_i];
+                _loop_2(inner);
+            }
+        };
+        var this_1 = this;
+        for (var _i = 0, outerArray_1 = outerArray; _i < outerArray_1.length; _i++) {
+            var outer = outerArray_1[_i];
+            _loop_1(outer);
+        }
+    }
+    Test.prototype.aFunction = function (func) {
+    };
+    return Test;
+}());
+exports.Test = Test;

tests/baselines/reference/nestedLoops.symbols

@@ -0,0 +1,46 @@
+=== tests/cases/compiler/nestedLoops.ts ===
+export class Test  {
+>Test : Symbol(Test, Decl(nestedLoops.ts, 0, 0))
+
+    constructor() {
+
+        let outerArray: Array<number> = [1, 2, 3];
+>outerArray : Symbol(outerArray, Decl(nestedLoops.ts, 3, 11))
+>Array : Symbol(Array, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+        let innerArray: Array<number> = [1, 2, 3];
+>innerArray : Symbol(innerArray, Decl(nestedLoops.ts, 4, 11))
+>Array : Symbol(Array, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+
+        for (let outer of outerArray)
+>outer : Symbol(outer, Decl(nestedLoops.ts, 6, 16))
+>outerArray : Symbol(outerArray, Decl(nestedLoops.ts, 3, 11))
+
+            for (let inner of innerArray) {
+>inner : Symbol(inner, Decl(nestedLoops.ts, 7, 20))
+>innerArray : Symbol(innerArray, Decl(nestedLoops.ts, 4, 11))
+
+                this.aFunction((newValue, oldValue) => {
+>this.aFunction : Symbol(Test.aFunction, Decl(nestedLoops.ts, 12, 5))
+>this : Symbol(Test, Decl(nestedLoops.ts, 0, 0))
+>aFunction : Symbol(Test.aFunction, Decl(nestedLoops.ts, 12, 5))
+>newValue : Symbol(newValue, Decl(nestedLoops.ts, 8, 32))
+>oldValue : Symbol(oldValue, Decl(nestedLoops.ts, 8, 41))
+
+                    let x = outer + inner + newValue;
+>x : Symbol(x, Decl(nestedLoops.ts, 9, 23))
+>outer : Symbol(outer, Decl(nestedLoops.ts, 6, 16))
+>inner : Symbol(inner, Decl(nestedLoops.ts, 7, 20))
+>newValue : Symbol(newValue, Decl(nestedLoops.ts, 8, 32))
+
+                });
+            }
+    }
+
+    public aFunction(func: (newValue: any, oldValue: any) => void): void {
+>aFunction : Symbol(Test.aFunction, Decl(nestedLoops.ts, 12, 5))
+>func : Symbol(func, Decl(nestedLoops.ts, 14, 21))
+>newValue : Symbol(newValue, Decl(nestedLoops.ts, 14, 28))
+>oldValue : Symbol(oldValue, Decl(nestedLoops.ts, 14, 42))
+    }
+}

tests/baselines/reference/nestedLoops.types

@@ -0,0 +1,58 @@
+=== tests/cases/compiler/nestedLoops.ts ===
+export class Test  {
+>Test : Test
+
+    constructor() {
+
+        let outerArray: Array<number> = [1, 2, 3];
+>outerArray : number[]
+>Array : T[]
+>[1, 2, 3] : number[]
+>1 : 1
+>2 : 2
+>3 : 3
+
+        let innerArray: Array<number> = [1, 2, 3];
+>innerArray : number[]
+>Array : T[]
+>[1, 2, 3] : number[]
+>1 : 1
+>2 : 2
+>3 : 3
+
+        for (let outer of outerArray)
+>outer : number
+>outerArray : number[]
+
+            for (let inner of innerArray) {
+>inner : number
+>innerArray : number[]
+
+                this.aFunction((newValue, oldValue) => {
+>this.aFunction((newValue, oldValue) => {                    let x = outer + inner + newValue;                }) : void
+>this.aFunction : (func: (newValue: any, oldValue: any) => void) => void
+>this : this
+>aFunction : (func: (newValue: any, oldValue: any) => void) => void
+>(newValue, oldValue) => {                    let x = outer + inner + newValue;                } : (newValue: any, oldValue: any) => void
+>newValue : any
+>oldValue : any
+
+                    let x = outer + inner + newValue;
+>x : any
+>outer + inner + newValue : any
+>outer + inner : number
+>outer : number
+>inner : number
+>newValue : any
+
+                });
+            }
+    }
+
+    public aFunction(func: (newValue: any, oldValue: any) => void): void {
+>aFunction : (func: (newValue: any, oldValue: any) => void) => void
+>func : (newValue: any, oldValue: any) => void
+>newValue : any
+>oldValue : any
+    }
+}

tests/cases/compiler/nestedLoops.ts

@@ -0,0 +1,18 @@
+// @target: es5
+export class Test  {
+    constructor() {
+
+        let outerArray: Array<number> = [1, 2, 3];
+        let innerArray: Array<number> = [1, 2, 3];
+
+        for (let outer of outerArray)
+            for (let inner of innerArray) {
+                this.aFunction((newValue, oldValue) => {
+                    let x = outer + inner + newValue;
+                });
+            }
+    }
+
+    public aFunction(func: (newValue: any, oldValue: any) => void): void {
+    }
+}