Allow extraction of type from type assertions for declaration emit

Author: dragomirtitian

src/compiler/transformers/declarations.ts

@@ -10,6 +10,7 @@ import {
     DiagnosticMessage,
     Diagnostics,
     ElementAccessExpression,
+    ExportAssignment,
     ExpressionWithTypeArguments,
     FunctionDeclaration,
     GetAccessorDeclaration,
@@ -24,6 +25,7 @@ import {
     isConstructorDeclaration,
     isConstructSignatureDeclaration,
     isElementAccessExpression,
+    isExportAssignment,
     isExpressionWithTypeArguments,
     isFunctionDeclaration,
     isGetAccessor,
@@ -100,7 +102,8 @@ export type DeclarationDiagnosticProducing =
     | BinaryExpression
     | JSDocTypedefTag
     | JSDocCallbackTag
-    | JSDocEnumTag;
+    | JSDocEnumTag
+    | ExportAssignment;
 
 /** @internal */
 export function canProduceDiagnostics(node: Node): node is DeclarationDiagnosticProducing {
@@ -231,9 +234,18 @@ export function createGetSymbolAccessibilityDiagnosticForNode(node: DeclarationD
     else if (isTypeAliasDeclaration(node) || isJSDocTypeAlias(node)) {
         return getTypeAliasDeclarationVisibilityError;
     }
+    else if (isExportAssignment(node)) {
+        return getExportAssignmentTypeVisibilityDiagnosticMessage;
+    }
     else {
         return Debug.assertNever(node, `Attempted to set a declaration diagnostic context for unhandled node kind: ${Debug.formatSyntaxKind((node as Node).kind)}`);
     }
+    function getExportAssignmentTypeVisibilityDiagnosticMessage() {
+        return {
+            diagnosticMessage: Diagnostics.Default_export_of_the_module_has_or_is_using_private_name_0,
+            errorNode: node,
+        };
+    }
 
     function getVariableDeclarationTypeVisibilityDiagnosticMessage(symbolAccessibilityResult: SymbolAccessibilityResult) {
         if (node.kind === SyntaxKind.VariableDeclaration || node.kind === SyntaxKind.BindingElement) {

src/compiler/transformers/declarations/diagnostics.ts

@@ -1,12 +1,9 @@
 accessorDeclarationEmitVisibilityErrors.ts(2,18): error TS2304: Cannot find name 'DoesNotExist'.
-accessorDeclarationEmitVisibilityErrors.ts(2,18): error TS4106: Parameter 'arg' of accessor has or is using private name 'DoesNotExist'.
 
 
-==== accessorDeclarationEmitVisibilityErrors.ts (2 errors) ====
+==== accessorDeclarationEmitVisibilityErrors.ts (1 errors) ====
     export class Q {
         set bet(arg: DoesNotExist) {}
                      ~~~~~~~~~~~~
 !!! error TS2304: Cannot find name 'DoesNotExist'.
-                     ~~~~~~~~~~~~
-!!! error TS4106: Parameter 'arg' of accessor has or is using private name 'DoesNotExist'.
     }

tests/baselines/reference/accessorDeclarationEmitVisibilityErrors.errors.txt

@@ -9,3 +9,9 @@ export class Q {
 export class Q {
     set bet(arg) { }
 }
+
+
+//// [accessorDeclarationEmitVisibilityErrors.d.ts]
+export declare class Q {
+    set bet(arg: DoesNotExist);
+}

tests/baselines/reference/accessorDeclarationEmitVisibilityErrors.js

@@ -70,7 +70,7 @@ interface Action<TName extends string, TPayload> {
     name: TName;
     payload: TPayload;
 }
-declare const actionA: Action<"ACTION_A", string>;
-declare const actionB: Action<"ACTION_B", boolean>;
+declare const actionA: Action<'ACTION_A', string>;
+declare const actionB: Action<'ACTION_B', boolean>;
 declare function call<TName extends string, TPayload>(action: Action<TName, TPayload>, fn: (action: Action<TName, TPayload>) => any): void;
 declare const printFn: (action: typeof actionA | typeof actionB) => void;

tests/baselines/reference/coAndContraVariantInferences.js

@@ -10,4 +10,5 @@ var x = {};
 //// [duplicatePropertiesInTypeAssertions02.d.ts]
 declare let x: {
     a: number;
+    a: number;
 };

tests/baselines/reference/duplicatePropertiesInTypeAssertions02.js

@@ -6,6 +6,6 @@ hugeDeclarationOutputGetsTruncatedWithError.ts(5,14): error TS7056: The inferred
 
     type manyprops = `${props}${props}`;
 
-    export const c = null as any as {[K in manyprops]: {[K2 in manyprops]: `${K}.${K2}`}};
+    export const c = () => null as any as {[K in manyprops]: {[K2 in manyprops]: `${K}.${K2}`}};
                  ~
 !!! error TS7056: The inferred type of this node exceeds the maximum length the compiler will serialize. An explicit type annotation is needed.

tests/baselines/reference/hugeDeclarationOutputGetsTruncatedWithError.errors.txt

@@ -5,10 +5,11 @@ type props = "a" | "b" | "c" | "d" | "e" | "f" | "g" | "h" | "i" | "j" | "k" | "
 
 type manyprops = `${props}${props}`;
 
-export const c = null as any as {[K in manyprops]: {[K2 in manyprops]: `${K}.${K2}`}};
+export const c = () => null as any as {[K in manyprops]: {[K2 in manyprops]: `${K}.${K2}`}};
 
 //// [hugeDeclarationOutputGetsTruncatedWithError.js]
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
 exports.c = void 0;
-exports.c = null;
+var c = function () { return null; };
+exports.c = c;

tests/baselines/reference/hugeDeclarationOutputGetsTruncatedWithError.js

@@ -9,12 +9,12 @@ type manyprops = `${props}${props}`;
 >props : Symbol(props, Decl(hugeDeclarationOutputGetsTruncatedWithError.ts, 0, 0))
 >props : Symbol(props, Decl(hugeDeclarationOutputGetsTruncatedWithError.ts, 0, 0))
 
-export const c = null as any as {[K in manyprops]: {[K2 in manyprops]: `${K}.${K2}`}};
+export const c = () => null as any as {[K in manyprops]: {[K2 in manyprops]: `${K}.${K2}`}};
 >c : Symbol(c, Decl(hugeDeclarationOutputGetsTruncatedWithError.ts, 4, 12))
->K : Symbol(K, Decl(hugeDeclarationOutputGetsTruncatedWithError.ts, 4, 34))
+>K : Symbol(K, Decl(hugeDeclarationOutputGetsTruncatedWithError.ts, 4, 40))
 >manyprops : Symbol(manyprops, Decl(hugeDeclarationOutputGetsTruncatedWithError.ts, 0, 167))
->K2 : Symbol(K2, Decl(hugeDeclarationOutputGetsTruncatedWithError.ts, 4, 53))
+>K2 : Symbol(K2, Decl(hugeDeclarationOutputGetsTruncatedWithError.ts, 4, 59))
 >manyprops : Symbol(manyprops, Decl(hugeDeclarationOutputGetsTruncatedWithError.ts, 0, 167))
->K : Symbol(K, Decl(hugeDeclarationOutputGetsTruncatedWithError.ts, 4, 34))
->K2 : Symbol(K2, Decl(hugeDeclarationOutputGetsTruncatedWithError.ts, 4, 53))
+>K : Symbol(K, Decl(hugeDeclarationOutputGetsTruncatedWithError.ts, 4, 40))
+>K2 : Symbol(K2, Decl(hugeDeclarationOutputGetsTruncatedWithError.ts, 4, 59))