Error on export default of type: issue https://github.com/microsoft/TypeScript/issues/55087

src/compiler/checker.ts

@@ -44682,6 +44682,9 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                             : Diagnostics.An_export_default_must_reference_a_value_when_verbatimModuleSyntax_is_enabled_but_0_only_refers_to_a_type,
                         idText(id));
                 }
+                else if (!node.isExportEquals && !(node.flags & NodeFlags.Ambient) && (getTypeOnlyAliasDeclaration(sym, /*include*/ undefined) || ((getAllSymbolFlags(sym) & SymbolFlags.Value) === 0))) {
+                    error(id, Diagnostics._0_only_refers_to_a_type_but_is_being_used_as_a_value_here, idText(id));
+                }
             }
             else {
                 checkExpressionCached(id); // doesn't resolve, check as expression to mark as error

tests/baselines/reference/allowSyntheticDefaultImportsCanPaintCrossModuleDeclaration.errors.txt

@@ -0,0 +1,16 @@
+color.ts(4,16): error TS2693: 'Color' only refers to a type, but is being used as a value here.
+
+
+==== color.ts (1 errors) ====
+    interface Color {
+        c: string;
+    }
+    export default Color;
+                   ~~~~~
+!!! error TS2693: 'Color' only refers to a type, but is being used as a value here.
+==== file1.ts (0 errors) ====
+    import Color from "./color";
+    export declare function styled(): Color;
+==== file2.ts (0 errors) ====
+    import { styled }  from "./file1";
+    export const A = styled();

tests/baselines/reference/declarationEmitToDeclarationDirWithCompositeOption.errors.txt

@@ -0,0 +1,16 @@
+/foo/test.ts(4,16): error TS2693: 'Foo' only refers to a type, but is being used as a value here.
+
+
+==== /foo/tsconfig.json (0 errors) ====
+    {
+        "compilerOptions": { "composite": true, "declarationDir": "out" }
+    }
+
+==== /foo/test.ts (1 errors) ====
+    interface Foo {
+        x: number;
+    }
+    export default Foo;
+                   ~~~
+!!! error TS2693: 'Foo' only refers to a type, but is being used as a value here.
+

tests/baselines/reference/declarationEmitToDeclarationDirWithDeclarationOption.errors.txt

@@ -0,0 +1,16 @@
+/foo/test.ts(4,16): error TS2693: 'Foo' only refers to a type, but is being used as a value here.
+
+
+==== /foo/tsconfig.json (0 errors) ====
+    {
+        "compilerOptions": { "declaration": true, "declarationDir": "out" }
+    }
+
+==== /foo/test.ts (1 errors) ====
+    interface Foo {
+        x: number;
+    }
+    export default Foo;
+                   ~~~
+!!! error TS2693: 'Foo' only refers to a type, but is being used as a value here.
+

tests/baselines/reference/declarationEmitToDeclarationDirWithoutCompositeAndDeclarationOptions.errors.txt

@@ -1,4 +1,5 @@
 /foo/tsconfig.json(2,26): error TS5069: Option 'declarationDir' cannot be specified without specifying option 'declaration' or option 'composite'.
+/foo/test.ts(4,16): error TS2693: 'Foo' only refers to a type, but is being used as a value here.
 
 
 ==== /foo/tsconfig.json (1 errors) ====
@@ -8,9 +9,11 @@
 !!! error TS5069: Option 'declarationDir' cannot be specified without specifying option 'declaration' or option 'composite'.
     }
 
-==== /foo/test.ts (0 errors) ====
+==== /foo/test.ts (1 errors) ====
     interface Foo {
         x: number;
     }
     export default Foo;
+                   ~~~
+!!! error TS2693: 'Foo' only refers to a type, but is being used as a value here.
 

tests/baselines/reference/declarationEmitWithComposite.errors.txt

@@ -0,0 +1,16 @@
+/foo/test.ts(4,16): error TS2693: 'Foo' only refers to a type, but is being used as a value here.
+
+
+==== /foo/tsconfig.json (0 errors) ====
+    {
+        "compilerOptions": { "composite": true, "outDir": "out" }
+    }
+
+==== /foo/test.ts (1 errors) ====
+    interface Foo {
+        x: number;
+    }
+    export default Foo;
+                   ~~~
+!!! error TS2693: 'Foo' only refers to a type, but is being used as a value here.
+

tests/baselines/reference/exportDefaultAlias_excludesEverything.errors.txt

@@ -1,8 +1,9 @@
 exportDefaultAlias_excludesEverything.ts(1,26): error TS2528: A module cannot have multiple default exports.
 exportDefaultAlias_excludesEverything.ts(3,16): error TS2528: A module cannot have multiple default exports.
+exportDefaultAlias_excludesEverything.ts(3,16): error TS2693: 'B' only refers to a type, but is being used as a value here.
 
 
-==== exportDefaultAlias_excludesEverything.ts (2 errors) ====
+==== exportDefaultAlias_excludesEverything.ts (3 errors) ====
     export default interface A {}
                              ~
 !!! error TS2528: A module cannot have multiple default exports.
@@ -12,4 +13,6 @@ exportDefaultAlias_excludesEverything.ts(3,16): error TS2528: A module cannot ha
                    ~
 !!! error TS2528: A module cannot have multiple default exports.
 !!! related TS2752 exportDefaultAlias_excludesEverything.ts:1:26: The first export default is here.
+                   ~
+!!! error TS2693: 'B' only refers to a type, but is being used as a value here.
 

tests/baselines/reference/exportDefaultForNonInstantiatedModule.errors.txt

@@ -0,0 +1,12 @@
+exportDefaultForNonInstantiatedModule.ts(6,16): error TS2693: 'm' only refers to a type, but is being used as a value here.
+
+
+==== exportDefaultForNonInstantiatedModule.ts (1 errors) ====
+    module m {
+        export interface foo {
+        }
+    }
+    // Should not be emitted
+    export default m;
+                   ~
+!!! error TS2693: 'm' only refers to a type, but is being used as a value here.

tests/baselines/reference/exportDefaultImportedType.errors.txt

@@ -0,0 +1,13 @@
+/main.ts(2,16): error TS2693: 'Foo' only refers to a type, but is being used as a value here.
+
+
+==== /exported.ts (0 errors) ====
+    type Foo = number;
+    export { Foo };
+
+==== /main.ts (1 errors) ====
+    import { Foo } from "./exported";
+    export default Foo;
+                   ~~~
+!!! error TS2693: 'Foo' only refers to a type, but is being used as a value here.
+

tests/baselines/reference/exportDefaultTypeAndClass.errors.txt

@@ -1,8 +1,9 @@
 exportDefaultTypeAndClass.ts(1,22): error TS2528: A module cannot have multiple default exports.
 exportDefaultTypeAndClass.ts(3,16): error TS2528: A module cannot have multiple default exports.
+exportDefaultTypeAndClass.ts(3,16): error TS2693: 'Bar' only refers to a type, but is being used as a value here.
 
 
-==== exportDefaultTypeAndClass.ts (2 errors) ====
+==== exportDefaultTypeAndClass.ts (3 errors) ====
     export default class Foo {}
                          ~~~
 !!! error TS2528: A module cannot have multiple default exports.
@@ -12,4 +13,6 @@ exportDefaultTypeAndClass.ts(3,16): error TS2528: A module cannot have multiple
                    ~~~
 !!! error TS2528: A module cannot have multiple default exports.
 !!! related TS2752 exportDefaultTypeAndClass.ts:1:22: The first export default is here.
+                   ~~~
+!!! error TS2693: 'Bar' only refers to a type, but is being used as a value here.
 

tests/baselines/reference/exportDefaultTypeAndFunctionOverloads.errors.txt

@@ -2,9 +2,10 @@ exportDefaultTypeAndFunctionOverloads.ts(1,25): error TS2528: A module cannot ha
 exportDefaultTypeAndFunctionOverloads.ts(2,25): error TS2528: A module cannot have multiple default exports.
 exportDefaultTypeAndFunctionOverloads.ts(3,25): error TS2528: A module cannot have multiple default exports.
 exportDefaultTypeAndFunctionOverloads.ts(7,16): error TS2528: A module cannot have multiple default exports.
+exportDefaultTypeAndFunctionOverloads.ts(7,16): error TS2693: 'Foo' only refers to a type, but is being used as a value here.
 
 
-==== exportDefaultTypeAndFunctionOverloads.ts (4 errors) ====
+==== exportDefaultTypeAndFunctionOverloads.ts (5 errors) ====
     export default function foo(value: number): number
                             ~~~
 !!! error TS2528: A module cannot have multiple default exports.
@@ -26,4 +27,6 @@ exportDefaultTypeAndFunctionOverloads.ts(7,16): error TS2528: A module cannot ha
 !!! related TS2752 exportDefaultTypeAndFunctionOverloads.ts:1:25: The first export default is here.
 !!! related TS2752 exportDefaultTypeAndFunctionOverloads.ts:2:25: The first export default is here.
 !!! related TS2752 exportDefaultTypeAndFunctionOverloads.ts:3:25: The first export default is here.
+                   ~~~
+!!! error TS2693: 'Foo' only refers to a type, but is being used as a value here.
 

tests/baselines/reference/exportDefaultTypeClassAndValue.errors.txt

@@ -3,9 +3,10 @@ exportDefaultTypeClassAndValue.ts(2,16): error TS2528: A module cannot have mult
 exportDefaultTypeClassAndValue.ts(3,22): error TS2323: Cannot redeclare exported variable 'default'.
 exportDefaultTypeClassAndValue.ts(3,22): error TS2528: A module cannot have multiple default exports.
 exportDefaultTypeClassAndValue.ts(5,16): error TS2528: A module cannot have multiple default exports.
+exportDefaultTypeClassAndValue.ts(5,16): error TS2693: 'Bar' only refers to a type, but is being used as a value here.
 
 
-==== exportDefaultTypeClassAndValue.ts (5 errors) ====
+==== exportDefaultTypeClassAndValue.ts (6 errors) ====
     const foo = 1
     export default foo
     ~~~~~~~~~~~~~~~~~~
@@ -25,4 +26,6 @@ exportDefaultTypeClassAndValue.ts(5,16): error TS2528: A module cannot have mult
 !!! error TS2528: A module cannot have multiple default exports.
 !!! related TS2752 exportDefaultTypeClassAndValue.ts:2:16: The first export default is here.
 !!! related TS2752 exportDefaultTypeClassAndValue.ts:3:22: The first export default is here.
+                   ~~~
+!!! error TS2693: 'Bar' only refers to a type, but is being used as a value here.
 

tests/baselines/reference/moduleAugmentationOfAlias.errors.txt

@@ -0,0 +1,21 @@
+/a.ts(2,16): error TS2693: 'I' only refers to a type, but is being used as a value here.
+
+
+==== /a.ts (1 errors) ====
+    interface I {}
+    export default I;
+                   ~
+!!! error TS2693: 'I' only refers to a type, but is being used as a value here.
+
+==== /b.ts (0 errors) ====
+    export {};
+    declare module './a' {
+        export default interface I { x: number; }
+    }
+
+==== /c.ts (0 errors) ====
+    import I from "./a";
+    function f(i: I) {
+        i.x;
+    }
+

tests/baselines/reference/tsbuild/demo/in-bad-ref-branch-reports-the-error-about-files-not-in-rootDir-at-the-import-location.js

@@ -157,6 +157,11 @@ Output::
 
 [12:00:09 AM] Building project '/src/core/tsconfig.json'...
 
+src/animals/index.ts:3:16 - error TS2693: 'Animal' only refers to a type, but is being used as a value here.
+
+3 export default Animal;
+                 ~~~~~~
+
 src/animals/index.ts:1:20 - error TS6059: File '/src/animals/animal.ts' is not under 'rootDir' '/src/core'. 'rootDir' is expected to contain all source files.
 
 1 import Animal from './animal';
@@ -217,13 +222,13 @@ Output::
 [12:00:18 AM] Skipping build of project '/src/zoo/tsconfig.json' because its dependency '/src/animals' was not built
 
 
-Found 7 errors.
+Found 8 errors.
 
 exitCode:: ExitStatus.DiagnosticsPresent_OutputsSkipped
 
 
 //// [/src/lib/core/tsconfig.tsbuildinfo]
-{"program":{"fileNames":["../../../lib/lib.d.ts","../../animals/animal.ts","../../animals/dog.ts","../../animals/index.ts","../../core/utilities.ts"],"fileInfos":[{"version":"3858781397-/// <reference no-default-lib=\"true\"/>\ninterface Boolean {}\ninterface Function {}\ninterface CallableFunction {}\ninterface NewableFunction {}\ninterface IArguments {}\ninterface Number { toExponential: any; }\ninterface Object {}\ninterface RegExp {}\ninterface String { charAt: any; }\ninterface Array<T> { length: number; [n: number]: T; }\ninterface ReadonlyArray<T> {}\ndeclare const console: { log(msg: any): void; };","affectsGlobalScope":true},"-14984181202-export type Size = \"small\" | \"medium\" | \"large\";\r\nexport default interface Animal {\r\n    size: Size;\r\n}\r\n","-10991948013-import Animal from '.';\r\nimport { makeRandomName } from '../core/utilities';\r\n\r\nexport interface Dog extends Animal {\r\n    woof(): void;\r\n    name: string;\r\n}\r\n\r\nexport function createDog(): Dog {\r\n    return ({\r\n        size: \"medium\",\r\n        woof: function(this: Dog) {\r\n            console.log(`${this.name} says \"Woof\"!`);\r\n        },\r\n        name: makeRandomName()\r\n    });\r\n}\r\n\r\n","-5382672599-import Animal from './animal';\r\n\r\nexport default Animal;\r\nimport { createDog, Dog } from './dog';\r\nexport { createDog, Dog };\r\n","-15713992787-import * as A from '../animals';\n\r\nexport function makeRandomName() {\r\n    return \"Bob!?! \";\r\n}\r\n\r\nexport function lastElementOf<T>(arr: T[]): T | undefined {\r\n    if (arr.length === 0) return undefined;\r\n    return arr[arr.length - 1];\r\n}\r\n\r\n"],"root":[5],"options":{"composite":true,"declaration":true,"module":1,"noFallthroughCasesInSwitch":true,"noImplicitReturns":true,"noUnusedLocals":true,"noUnusedParameters":true,"outDir":"./","rootDir":"../../core","strict":true,"target":1},"fileIdsList":[[4,5],[2,3],[4]],"referencedMap":[[3,1],[4,2],[5,3]],"exportedModulesMap":[[3,1],[4,2],[5,3]],"semanticDiagnosticsPerFile":[1,2,3,4,[5,[{"file":"../../core/utilities.ts","start":0,"length":32,"messageText":"'A' is declared but its value is never read.","category":1,"code":6133,"reportsUnnecessary":true}]]],"affectedFilesPendingEmit":[2,3,4,5],"emitSignatures":[2,3,4,5]},"version":"FakeTSVersion"}
+{"program":{"fileNames":["../../../lib/lib.d.ts","../../animals/animal.ts","../../animals/dog.ts","../../animals/index.ts","../../core/utilities.ts"],"fileInfos":[{"version":"3858781397-/// <reference no-default-lib=\"true\"/>\ninterface Boolean {}\ninterface Function {}\ninterface CallableFunction {}\ninterface NewableFunction {}\ninterface IArguments {}\ninterface Number { toExponential: any; }\ninterface Object {}\ninterface RegExp {}\ninterface String { charAt: any; }\ninterface Array<T> { length: number; [n: number]: T; }\ninterface ReadonlyArray<T> {}\ndeclare const console: { log(msg: any): void; };","affectsGlobalScope":true},"-14984181202-export type Size = \"small\" | \"medium\" | \"large\";\r\nexport default interface Animal {\r\n    size: Size;\r\n}\r\n","-10991948013-import Animal from '.';\r\nimport { makeRandomName } from '../core/utilities';\r\n\r\nexport interface Dog extends Animal {\r\n    woof(): void;\r\n    name: string;\r\n}\r\n\r\nexport function createDog(): Dog {\r\n    return ({\r\n        size: \"medium\",\r\n        woof: function(this: Dog) {\r\n            console.log(`${this.name} says \"Woof\"!`);\r\n        },\r\n        name: makeRandomName()\r\n    });\r\n}\r\n\r\n","-5382672599-import Animal from './animal';\r\n\r\nexport default Animal;\r\nimport { createDog, Dog } from './dog';\r\nexport { createDog, Dog };\r\n","-15713992787-import * as A from '../animals';\n\r\nexport function makeRandomName() {\r\n    return \"Bob!?! \";\r\n}\r\n\r\nexport function lastElementOf<T>(arr: T[]): T | undefined {\r\n    if (arr.length === 0) return undefined;\r\n    return arr[arr.length - 1];\r\n}\r\n\r\n"],"root":[5],"options":{"composite":true,"declaration":true,"module":1,"noFallthroughCasesInSwitch":true,"noImplicitReturns":true,"noUnusedLocals":true,"noUnusedParameters":true,"outDir":"./","rootDir":"../../core","strict":true,"target":1},"fileIdsList":[[4,5],[2,3],[4]],"referencedMap":[[3,1],[4,2],[5,3]],"exportedModulesMap":[[3,1],[4,2],[5,3]],"semanticDiagnosticsPerFile":[1,2,3,[4,[{"file":"../../animals/index.ts","start":49,"length":6,"messageText":"'Animal' only refers to a type, but is being used as a value here.","category":1,"code":2693}]],[5,[{"file":"../../core/utilities.ts","start":0,"length":32,"messageText":"'A' is declared but its value is never read.","category":1,"code":6133,"reportsUnnecessary":true}]]],"affectedFilesPendingEmit":[2,3,4,5],"emitSignatures":[2,3,4,5]},"version":"FakeTSVersion"}
 
 //// [/src/lib/core/tsconfig.tsbuildinfo.readable.baseline.txt]
 {
@@ -324,7 +329,19 @@ exitCode:: ExitStatus.DiagnosticsPresent_OutputsSkipped
       "../../../lib/lib.d.ts",
       "../../animals/animal.ts",
       "../../animals/dog.ts",
-      "../../animals/index.ts",
+      [
+        "../../animals/index.ts",
+        [
+          {
+            "file": "../../animals/index.ts",
+            "start": 49,
+            "length": 6,
+            "messageText": "'Animal' only refers to a type, but is being used as a value here.",
+            "category": 1,
+            "code": 2693
+          }
+        ]
+      ],
       [
         "../../core/utilities.ts",
         [
@@ -366,6 +383,6 @@ exitCode:: ExitStatus.DiagnosticsPresent_OutputsSkipped
     ]
   },
   "version": "FakeTSVersion",
-  "size": 2309
+  "size": 2477
 }