Merge pull request #16282 from Microsoft/fix16086

Fix emit when type import merges with local value

Author: rbuckton

Diff for: Jakefile.js

@@ -926,7 +926,7 @@ function runConsoleTests(defaultReporter, runInParallel) {
     }
 }
 
-var defaultTestTimeout = 20000;
+var defaultTestTimeout = 22000;
 desc("Runs all the tests in parallel using the built run.js file. Optional arguments are: t[ests]=category1|category2|... d[ebug]=true.");
 task("runtests-parallel", ["build-rules", "tests", builtLocalDirectory], function () {
     runConsoleTests('min', /*runInParallel*/ true);

Diff for: src/compiler/checker.ts

@@ -1473,8 +1473,15 @@ namespace ts {
             }
         }
 
+        /**
+         * Indicates that a symbol is an alias that does not merge with a local declaration.
+         */
+        function isNonLocalAlias(symbol: Symbol, excludes = SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace) {
+            return symbol && (symbol.flags & (SymbolFlags.Alias | excludes)) === SymbolFlags.Alias;
+        }
+
         function resolveSymbol(symbol: Symbol, dontResolveAlias?: boolean): Symbol {
-            const shouldResolve = !dontResolveAlias && symbol && symbol.flags & SymbolFlags.Alias && !(symbol.flags & (SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace));
+            const shouldResolve = !dontResolveAlias && isNonLocalAlias(symbol);
             return shouldResolve ? resolveAlias(symbol) : symbol;
         }
 
@@ -12020,7 +12027,9 @@ namespace ts {
                 return getTypeOfSymbol(symbol);
             }
 
-            if (symbol.flags & SymbolFlags.Alias && !isInTypeQuery(node) && !isConstEnumOrConstEnumOnlyModule(resolveAlias(symbol))) {
+            // We should only mark aliases as referenced if there isn't a local value declaration
+            // for the symbol.
+            if (isNonLocalAlias(symbol, /*excludes*/ SymbolFlags.Value) && !isInTypeQuery(node) && !isConstEnumOrConstEnumOnlyModule(resolveAlias(symbol))) {
                 markAliasSymbolAsReferenced(symbol);
             }
 
@@ -22926,7 +22935,9 @@ namespace ts {
             node = getParseTreeNode(node, isIdentifier);
             if (node) {
                 const symbol = getReferencedValueSymbol(node);
-                if (symbol && symbol.flags & SymbolFlags.Alias) {
+                // We should only get the declaration of an alias if there isn't a local value
+                // declaration for the symbol
+                if (isNonLocalAlias(symbol, /*excludes*/ SymbolFlags.Value)) {
                     return getDeclarationOfAliasSymbol(symbol);
                 }
             }

Diff for: tests/baselines/reference/symbolMergeValueAndImportedType.js

@@ -0,0 +1,17 @@
+//// [tests/cases/compiler/symbolMergeValueAndImportedType.ts] ////
+
+//// [main.ts]
+import { X } from "./other";
+const X = 42;
+console.log('X is ' + X);
+//// [other.ts]
+export type X = {};
+
+//// [other.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+//// [main.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+const X = 42;
+console.log('X is ' + X);

Diff for: tests/baselines/reference/symbolMergeValueAndImportedType.symbols

@@ -0,0 +1,17 @@
+=== tests/cases/compiler/main.ts ===
+import { X } from "./other";
+>X : Symbol(X, Decl(main.ts, 0, 8), Decl(main.ts, 1, 5))
+
+const X = 42;
+>X : Symbol(X, Decl(main.ts, 0, 8), Decl(main.ts, 1, 5))
+
+console.log('X is ' + X);
+>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
+>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>X : Symbol(X, Decl(main.ts, 0, 8), Decl(main.ts, 1, 5))
+
+=== tests/cases/compiler/other.ts ===
+export type X = {};
+>X : Symbol(X, Decl(other.ts, 0, 0))
+

Diff for: tests/baselines/reference/symbolMergeValueAndImportedType.types

@@ -0,0 +1,21 @@
+=== tests/cases/compiler/main.ts ===
+import { X } from "./other";
+>X : 42
+
+const X = 42;
+>X : 42
+>42 : 42
+
+console.log('X is ' + X);
+>console.log('X is ' + X) : void
+>console.log : (message?: any, ...optionalParams: any[]) => void
+>console : Console
+>log : (message?: any, ...optionalParams: any[]) => void
+>'X is ' + X : string
+>'X is ' : "X is "
+>X : 42
+
+=== tests/cases/compiler/other.ts ===
+export type X = {};
+>X : X
+

Diff for: tests/cases/compiler/symbolMergeValueAndImportedType.ts

@@ -0,0 +1,9 @@
+// @target: es2015
+// @module: commonjs
+// @lib: es2015,dom
+// @filename: main.ts
+import { X } from "./other";
+const X = 42;
+console.log('X is ' + X);
+// @filename: other.ts
+export type X = {};