Add fix for crash in #18712 (#18751)

src/compiler/checker.ts

@@ -19274,10 +19274,11 @@ namespace ts {
                             : DeclarationSpaces.ExportNamespace;
                     case SyntaxKind.ClassDeclaration:
                     case SyntaxKind.EnumDeclaration:
-                    // A NamespaceImport declares an Alias, which is allowed to merge with other values within the module
-                    case SyntaxKind.NamespaceImport:
                         return DeclarationSpaces.ExportType | DeclarationSpaces.ExportValue;
+                    // The below options all declare an Alias, which is allowed to merge with other values within the importing module
                     case SyntaxKind.ImportEqualsDeclaration:
+                    case SyntaxKind.NamespaceImport:
+                    case SyntaxKind.ImportClause:
                         let result = DeclarationSpaces.None;
                         const target = resolveAlias(getSymbolOfNode(d));
                         forEach(target.declarations, d => { result |= getDeclarationSpaces(d); });

tests/baselines/reference/allowImportClausesToMergeWithTypes.errors.txt

@@ -0,0 +1,34 @@
+tests/cases/compiler/index.ts(4,1): error TS2693: 'zzz' only refers to a type, but is being used as a value here.
+tests/cases/compiler/index.ts(9,10): error TS2304: Cannot find name 'originalZZZ'.
+
+
+==== tests/cases/compiler/b.ts (0 errors) ====
+    export const zzz = 123;
+    export default zzz;
+    
+==== tests/cases/compiler/a.ts (0 errors) ====
+    export default interface zzz {
+        x: string;
+    }
+    
+    import zzz from "./b";
+    
+    const x: zzz = { x: "" };
+    zzz;
+    
+    export { zzz as default };
+    
+==== tests/cases/compiler/index.ts (2 errors) ====
+    import zzz from "./a";
+    
+    const x: zzz = { x: "" };
+    zzz;
+    ~~~
+!!! error TS2693: 'zzz' only refers to a type, but is being used as a value here.
+    
+    import originalZZZ from "./b";
+    originalZZZ;
+    
+    const y: originalZZZ = x;
+             ~~~~~~~~~~~
+!!! error TS2304: Cannot find name 'originalZZZ'.

tests/baselines/reference/allowImportClausesToMergeWithTypes.js

@@ -0,0 +1,49 @@
+//// [tests/cases/compiler/allowImportClausesToMergeWithTypes.ts] ////
+
+//// [b.ts]
+export const zzz = 123;
+export default zzz;
+
+//// [a.ts]
+export default interface zzz {
+    x: string;
+}
+
+import zzz from "./b";
+
+const x: zzz = { x: "" };
+zzz;
+
+export { zzz as default };
+
+//// [index.ts]
+import zzz from "./a";
+
+const x: zzz = { x: "" };
+zzz;
+
+import originalZZZ from "./b";
+originalZZZ;
+
+const y: originalZZZ = x;
+
+//// [b.js]
+"use strict";
+exports.__esModule = true;
+exports.zzz = 123;
+exports["default"] = exports.zzz;
+//// [a.js]
+"use strict";
+exports.__esModule = true;
+var b_1 = require("./b");
+exports["default"] = b_1["default"];
+var x = { x: "" };
+b_1["default"];
+//// [index.js]
+"use strict";
+exports.__esModule = true;
+var x = { x: "" };
+zzz;
+var b_1 = require("./b");
+b_1["default"];
+var y = x;

tests/baselines/reference/allowImportClausesToMergeWithTypes.symbols

@@ -0,0 +1,51 @@
+=== tests/cases/compiler/b.ts ===
+export const zzz = 123;
+>zzz : Symbol(zzz, Decl(b.ts, 0, 12))
+
+export default zzz;
+>zzz : Symbol(zzz, Decl(b.ts, 0, 12))
+
+=== tests/cases/compiler/a.ts ===
+export default interface zzz {
+>zzz : Symbol(zzz, Decl(a.ts, 0, 0), Decl(a.ts, 9, 8))
+
+    x: string;
+>x : Symbol(zzz.x, Decl(a.ts, 0, 30))
+}
+
+import zzz from "./b";
+>zzz : Symbol(zzz, Decl(a.ts, 0, 0), Decl(a.ts, 4, 6))
+
+const x: zzz = { x: "" };
+>x : Symbol(x, Decl(a.ts, 6, 5))
+>zzz : Symbol(zzz, Decl(a.ts, 0, 0), Decl(a.ts, 9, 8))
+>x : Symbol(x, Decl(a.ts, 6, 16))
+
+zzz;
+>zzz : Symbol(zzz, Decl(a.ts, 0, 0), Decl(a.ts, 4, 6))
+
+export { zzz as default };
+>zzz : Symbol(zzz, Decl(a.ts, 0, 0), Decl(a.ts, 9, 8))
+>default : Symbol(zzz, Decl(a.ts, 0, 0), Decl(a.ts, 9, 8))
+
+=== tests/cases/compiler/index.ts ===
+import zzz from "./a";
+>zzz : Symbol(zzz, Decl(index.ts, 0, 6))
+
+const x: zzz = { x: "" };
+>x : Symbol(x, Decl(index.ts, 2, 5))
+>zzz : Symbol(zzz, Decl(index.ts, 0, 6))
+>x : Symbol(x, Decl(index.ts, 2, 16))
+
+zzz;
+
+import originalZZZ from "./b";
+>originalZZZ : Symbol(originalZZZ, Decl(index.ts, 5, 6))
+
+originalZZZ;
+>originalZZZ : Symbol(originalZZZ, Decl(index.ts, 5, 6))
+
+const y: originalZZZ = x;
+>y : Symbol(y, Decl(index.ts, 8, 5))
+>x : Symbol(x, Decl(index.ts, 2, 5))
+

tests/baselines/reference/allowImportClausesToMergeWithTypes.types

@@ -0,0 +1,58 @@
+=== tests/cases/compiler/b.ts ===
+export const zzz = 123;
+>zzz : 123
+>123 : 123
+
+export default zzz;
+>zzz : 123
+
+=== tests/cases/compiler/a.ts ===
+export default interface zzz {
+>zzz : zzz
+
+    x: string;
+>x : string
+}
+
+import zzz from "./b";
+>zzz : 123
+
+const x: zzz = { x: "" };
+>x : zzz
+>zzz : zzz
+>{ x: "" } : { x: string; }
+>x : string
+>"" : ""
+
+zzz;
+>zzz : 123
+
+export { zzz as default };
+>zzz : 123
+>default : 123
+
+=== tests/cases/compiler/index.ts ===
+import zzz from "./a";
+>zzz : any
+
+const x: zzz = { x: "" };
+>x : zzz
+>zzz : zzz
+>{ x: "" } : { x: string; }
+>x : string
+>"" : ""
+
+zzz;
+>zzz : any
+
+import originalZZZ from "./b";
+>originalZZZ : 123
+
+originalZZZ;
+>originalZZZ : 123
+
+const y: originalZZZ = x;
+>y : any
+>originalZZZ : No type information available!
+>x : zzz
+

tests/cases/compiler/allowImportClausesToMergeWithTypes.ts

@@ -0,0 +1,26 @@
+// @filename: b.ts
+export const zzz = 123;
+export default zzz;
+
+// @filename: a.ts
+export default interface zzz {
+    x: string;
+}
+
+import zzz from "./b";
+
+const x: zzz = { x: "" };
+zzz;
+
+export { zzz as default };
+
+// @filename: index.ts
+import zzz from "./a";
+
+const x: zzz = { x: "" };
+zzz;
+
+import originalZZZ from "./b";
+originalZZZ;
+
+const y: originalZZZ = x;