Fix merge lexical environment to *always* respect prologue statements (microsoft#24602)

weswigham · web-flow · commit 779fa9847515 · 2018-06-04T10:34:38.000-07:00
diff --git a/src/compiler/visitor.ts b/src/compiler/visitor.ts
@@ -1468,7 +1468,7 @@ namespace ts {
         }
 
         return isNodeArray(statements)
-            ? setTextRange(createNodeArray(concatenate(declarations, statements)), statements)
+            ? setTextRange(createNodeArray(prependStatements(statements.slice(), declarations)), statements)
             : prependStatements(statements, declarations);
     }
 
diff --git a/tests/baselines/reference/destructuringTempOccursAfterPrologue.js b/tests/baselines/reference/destructuringTempOccursAfterPrologue.js
@@ -0,0 +1,12 @@
+//// [destructuringTempOccursAfterPrologue.ts]
+function test(p: any) {
+    'use strict';
+    p = { prop: p } = p;
+}
+
+//// [destructuringTempOccursAfterPrologue.js]
+function test(p) {
+    'use strict';
+    var _a;
+    p = (_a = p, p = _a.prop, _a);
+}
diff --git a/tests/baselines/reference/destructuringTempOccursAfterPrologue.symbols b/tests/baselines/reference/destructuringTempOccursAfterPrologue.symbols
@@ -0,0 +1,12 @@
+=== tests/cases/compiler/destructuringTempOccursAfterPrologue.ts ===
+function test(p: any) {
+>test : Symbol(test, Decl(destructuringTempOccursAfterPrologue.ts, 0, 0))
+>p : Symbol(p, Decl(destructuringTempOccursAfterPrologue.ts, 0, 14))
+
+    'use strict';
+    p = { prop: p } = p;
+>p : Symbol(p, Decl(destructuringTempOccursAfterPrologue.ts, 0, 14))
+>prop : Symbol(prop, Decl(destructuringTempOccursAfterPrologue.ts, 2, 9))
+>p : Symbol(p, Decl(destructuringTempOccursAfterPrologue.ts, 0, 14))
+>p : Symbol(p, Decl(destructuringTempOccursAfterPrologue.ts, 0, 14))
+}
diff --git a/tests/baselines/reference/destructuringTempOccursAfterPrologue.types b/tests/baselines/reference/destructuringTempOccursAfterPrologue.types
@@ -0,0 +1,17 @@
+=== tests/cases/compiler/destructuringTempOccursAfterPrologue.ts ===
+function test(p: any) {
+>test : (p: any) => void
+>p : any
+
+    'use strict';
+>'use strict' : "use strict"
+
+    p = { prop: p } = p;
+>p = { prop: p } = p : any
+>p : any
+>{ prop: p } = p : any
+>{ prop: p } : { prop: any; }
+>prop : any
+>p : any
+>p : any
+}
diff --git a/tests/cases/compiler/destructuringTempOccursAfterPrologue.ts b/tests/cases/compiler/destructuringTempOccursAfterPrologue.ts
@@ -0,0 +1,4 @@
+function test(p: any) {
+    'use strict';
+    p = { prop: p } = p;
+}

Original file line number	Diff line number	Diff line change
`@@ -1468,7 +1468,7 @@ namespace ts {`
`1468`	`1468`	`}`
`1469`	`1469`
`1470`	`1470`	`return isNodeArray(statements)`
`1471`		`- ? setTextRange(createNodeArray(concatenate(declarations, statements)), statements)`
	`1471`	`+ ? setTextRange(createNodeArray(prependStatements(statements.slice(), declarations)), statements)`
`1472`	`1472`	`: prependStatements(statements, declarations);`
`1473`	`1473`	`}`
`1474`	`1474`