Error if type node uses inaccessible type in isolated declarations

src/compiler/checker.ts

@@ -6085,6 +6085,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                     return result;
                 }
             }
+            context.tracker.reportInferenceFallback(existing);
             return undefined;
         }
 
@@ -8301,6 +8302,10 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                     // If the symbol is found both in declaration scope and in current scope then it shoudl point to the same reference
                     (symAtLocation && sym && !getSymbolIfSameReference(getExportSymbolOfValueSymbolIfExported(symAtLocation), sym))
                 ) {
+                    // In isolated declaration we will not do rest parameter expansion so there is no need to report on these.
+                    if (symAtLocation !== unknownSymbol) {
+                        context.tracker.reportInferenceFallback(node);
+                    }
                     introducesError = true;
                     return { introducesError, node, sym };
                 }
@@ -8321,6 +8326,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                     !isDeclarationName(node) &&
                     isSymbolAccessible(sym, context.enclosingDeclaration, meaning, /*shouldComputeAliasesToMakeVisible*/ false).accessibility !== SymbolAccessibility.Accessible
                 ) {
+                    context.tracker.reportInferenceFallback(node);
                     introducesError = true;
                 }
                 else {

src/compiler/diagnosticMessages.json

@@ -7018,6 +7018,10 @@
         "category": "Error",
         "code": 9038
     },
+    "Type containing private name '{0}' can't be used with --isolatedDeclarations.": {
+        "category": "Error",
+        "code": 9039
+    },
     "JSX attributes must only be assigned a non-empty 'expression'.": {
         "category": "Error",
         "code": 17000

src/compiler/transformers/declarations/diagnostics.ts

@@ -19,12 +19,14 @@ import {
     DiagnosticWithLocation,
     ElementAccessExpression,
     EmitResolver,
+    EntityNameOrEntityNameExpression,
     ExportAssignment,
     Expression,
     ExpressionWithTypeArguments,
     findAncestor,
     FunctionDeclaration,
     FunctionExpression,
+    FunctionLikeDeclaration,
     GetAccessorDeclaration,
     getAllAccessorDeclarations,
     getNameOfDeclaration,
@@ -40,9 +42,12 @@ import {
     isConstructorDeclaration,
     isConstructSignatureDeclaration,
     isElementAccessExpression,
+    isEntityName,
+    isEntityNameExpression,
     isExportAssignment,
     isExpressionWithTypeArguments,
     isFunctionDeclaration,
+    isFunctionLikeDeclaration,
     isGetAccessor,
     isHeritageClause,
     isImportEqualsDeclaration,
@@ -53,15 +58,18 @@ import {
     isParameter,
     isParameterPropertyDeclaration,
     isParenthesizedExpression,
+    isPartOfTypeNode,
     isPropertyAccessExpression,
     isPropertyDeclaration,
     isPropertySignature,
+    isReturnStatement,
     isSetAccessor,
     isStatement,
     isStatic,
     isTypeAliasDeclaration,
     isTypeAssertionExpression,
     isTypeParameterDeclaration,
+    isTypeQueryNode,
     isVariableDeclaration,
     JSDocCallbackTag,
     JSDocEnumTag,
@@ -658,6 +666,9 @@ export function createGetIsolatedDeclarationErrors(resolver: EmitResolver) {
         if (heritageClause) {
             return createDiagnosticForNode(node, Diagnostics.Extends_clause_can_t_contain_an_expression_with_isolatedDeclarations);
         }
+        if ((isPartOfTypeNode(node) || isTypeQueryNode(node.parent)) && (isEntityName(node) || isEntityNameExpression(node))) {
+            return createEntityInTypeNodeError(node);
+        }
         Debug.type<WithIsolatedDeclarationDiagnostic>(node);
         switch (node.kind) {
             case SyntaxKind.GetAccessor:
@@ -694,8 +705,15 @@ export function createGetIsolatedDeclarationErrors(resolver: EmitResolver) {
     }
 
     function findNearestDeclaration(node: Node) {
-        const result = findAncestor(node, n => isExportAssignment(n) || (isStatement(n) ? "quit" : isVariableDeclaration(n) || isPropertyDeclaration(n) || isParameter(n)));
-        return result as VariableDeclaration | PropertyDeclaration | ParameterDeclaration | ExportAssignment | undefined;
+        const result = findAncestor(node, n => isExportAssignment(n) || isStatement(n) || isVariableDeclaration(n) || isPropertyDeclaration(n) || isParameter(n));
+        if (!result) return undefined;
+
+        if (isExportAssignment(result)) return result;
+
+        if (isReturnStatement(result)) {
+            return findAncestor(result, (n): n is Exclude<FunctionLikeDeclaration, ConstructorDeclaration> => isFunctionLikeDeclaration(n) && !isConstructorDeclaration(n));
+        }
+        return (isStatement(result) ? undefined : result) as VariableDeclaration | PropertyDeclaration | ParameterDeclaration | ExportAssignment | undefined;
     }
 
     function createAccessorTypeError(node: GetAccessorDeclaration | SetAccessorDeclaration) {
@@ -712,31 +730,27 @@ export function createGetIsolatedDeclarationErrors(resolver: EmitResolver) {
         }
         return diag;
     }
-    function createObjectLiteralError(node: ShorthandPropertyAssignment | SpreadAssignment | ComputedPropertyName) {
-        const diag = createDiagnosticForNode(node, errorByDeclarationKind[node.kind]);
+    function addParentDeclarationRelatedInfo(node: Node, diag: DiagnosticWithLocation) {
         const parentDeclaration = findNearestDeclaration(node);
         if (parentDeclaration) {
-            const targetStr = isExportAssignment(parentDeclaration) ? "" : getTextOfNode(parentDeclaration.name, /*includeTrivia*/ false);
+            const targetStr = isExportAssignment(parentDeclaration) || !parentDeclaration.name ? "" : getTextOfNode(parentDeclaration.name, /*includeTrivia*/ false);
             addRelatedInfo(diag, createDiagnosticForNode(parentDeclaration, relatedSuggestionByDeclarationKind[parentDeclaration.kind], targetStr));
         }
         return diag;
     }
+    function createObjectLiteralError(node: ShorthandPropertyAssignment | SpreadAssignment | ComputedPropertyName) {
+        const diag = createDiagnosticForNode(node, errorByDeclarationKind[node.kind]);
+        addParentDeclarationRelatedInfo(node, diag);
+        return diag;
+    }
     function createArrayLiteralError(node: ArrayLiteralExpression | SpreadElement) {
         const diag = createDiagnosticForNode(node, errorByDeclarationKind[node.kind]);
-        const parentDeclaration = findNearestDeclaration(node);
-        if (parentDeclaration) {
-            const targetStr = isExportAssignment(parentDeclaration) ? "" : getTextOfNode(parentDeclaration.name, /*includeTrivia*/ false);
-            addRelatedInfo(diag, createDiagnosticForNode(parentDeclaration, relatedSuggestionByDeclarationKind[parentDeclaration.kind], targetStr));
-        }
+        addParentDeclarationRelatedInfo(node, diag);
         return diag;
     }
     function createReturnTypeError(node: FunctionDeclaration | FunctionExpression | ArrowFunction | MethodDeclaration | ConstructSignatureDeclaration) {
         const diag = createDiagnosticForNode(node, errorByDeclarationKind[node.kind]);
-        const parentDeclaration = findNearestDeclaration(node);
-        if (parentDeclaration) {
-            const targetStr = isExportAssignment(parentDeclaration) ? "" : getTextOfNode(parentDeclaration.name, /*includeTrivia*/ false);
-            addRelatedInfo(diag, createDiagnosticForNode(parentDeclaration, relatedSuggestionByDeclarationKind[parentDeclaration.kind], targetStr));
-        }
+        addParentDeclarationRelatedInfo(node, diag);
         addRelatedInfo(diag, createDiagnosticForNode(node, relatedSuggestionByDeclarationKind[node.kind]));
         return diag;
     }
@@ -768,12 +782,18 @@ export function createGetIsolatedDeclarationErrors(resolver: EmitResolver) {
     function createClassExpressionError(node: Expression) {
         return createExpressionError(node, Diagnostics.Inference_from_class_expressions_is_not_supported_with_isolatedDeclarations);
     }
+    function createEntityInTypeNodeError(node: EntityNameOrEntityNameExpression) {
+        const diag = createDiagnosticForNode(node, Diagnostics.Type_containing_private_name_0_can_t_be_used_with_isolatedDeclarations, getTextOfNode(node, /*includeTrivia*/ false));
+        addParentDeclarationRelatedInfo(node, diag);
+        return diag;
+    }
     function createExpressionError(node: Expression, diagnosticMessage?: DiagnosticMessage) {
         const parentDeclaration = findNearestDeclaration(node);
         let diag: DiagnosticWithLocation;
         if (parentDeclaration) {
-            const targetStr = isExportAssignment(parentDeclaration) ? "" : getTextOfNode(parentDeclaration.name, /*includeTrivia*/ false);
+            const targetStr = isExportAssignment(parentDeclaration) || !parentDeclaration.name ? "" : getTextOfNode(parentDeclaration.name, /*includeTrivia*/ false);
             const parent = findAncestor(node.parent, n => isExportAssignment(n) || (isStatement(n) ? "quit" : !isParenthesizedExpression(n) && !isTypeAssertionExpression(n) && !isAsExpression(n)));
+
             if (parentDeclaration === parent) {
                 diag = createDiagnosticForNode(node, diagnosticMessage ?? errorByDeclarationKind[parentDeclaration.kind]);
                 addRelatedInfo(diag, createDiagnosticForNode(parentDeclaration, relatedSuggestionByDeclarationKind[parentDeclaration.kind], targetStr));

src/services/codefixes/fixMissingTypeAnnotationOnExports.ts

@@ -65,6 +65,7 @@ import {
     isSpreadAssignment,
     isSpreadElement,
     isStatement,
+    isTypeNode,
     isValueSignatureDeclaration,
     isVariableDeclaration,
     ModifierFlags,
@@ -132,6 +133,7 @@ const errorCodes = [
     Diagnostics.Only_const_arrays_can_be_inferred_with_isolatedDeclarations.code,
     Diagnostics.Assigning_properties_to_functions_without_declaring_them_is_not_supported_with_isolatedDeclarations_Add_an_explicit_declaration_for_the_properties_assigned_to_this_function.code,
     Diagnostics.Declaration_emit_for_this_parameter_requires_implicitly_adding_undefined_to_it_s_type_This_is_not_supported_with_isolatedDeclarations.code,
+    Diagnostics.Type_containing_private_name_0_can_t_be_used_with_isolatedDeclarations.code,
     Diagnostics.Add_satisfies_and_a_type_assertion_to_this_expression_satisfies_T_as_T_to_make_the_type_explicit.code,
 ];
 
@@ -352,7 +354,7 @@ function withContext<T>(
             return undefined;
         }
         // No support for typeof in extends clauses
-        if (isExpressionTarget && findAncestor(targetNode, isHeritageClause)) {
+        if (isExpressionTarget && (findAncestor(targetNode, isHeritageClause) || findAncestor(targetNode, isTypeNode))) {
             return undefined;
         }
         // Can't inline type spread elements. Whatever you do isolated declarations will not infer from them

tests/baselines/reference/transpile/declarationNotInScopeTypes.d.ts

@@ -0,0 +1,49 @@
+//// [variables.ts] ////
+const x = "";
+export function one() {
+    return {} as typeof x;
+}
+
+export function two() {
+    const y = "";
+    return {} as typeof y;
+}
+
+export function three() {
+    type Z = string;
+    return {} as Z;
+}
+//// [variables.d.ts] ////
+declare const x = "";
+export declare function one(): typeof x;
+export declare function two(): "";
+export declare function three(): string;
+export {};
+
+
+//// [Diagnostics reported]
+variables.ts(8,25): error TS9039: Type containing private name 'y' can't be used with --isolatedDeclarations.
+variables.ts(13,18): error TS9039: Type containing private name 'Z' can't be used with --isolatedDeclarations.
+
+
+==== variables.ts (2 errors) ====
+    const x = "";
+    export function one() {
+        return {} as typeof x;
+    }
+
+    export function two() {
+        const y = "";
+        return {} as typeof y;
+                            ~
+!!! error TS9039: Type containing private name 'y' can't be used with --isolatedDeclarations.
+!!! related TS9031 variables.ts:6:17: Add a return type to the function declaration.
+    }
+
+    export function three() {
+        type Z = string;
+        return {} as Z;
+                     ~
+!!! error TS9039: Type containing private name 'Z' can't be used with --isolatedDeclarations.
+!!! related TS9031 variables.ts:11:17: Add a return type to the function declaration.
+    }

tests/baselines/reference/transpile/declarationNotInScopeTypes.js

@@ -0,0 +1,27 @@
+//// [variables.ts] ////
+const x = "";
+export function one() {
+    return {} as typeof x;
+}
+
+export function two() {
+    const y = "";
+    return {} as typeof y;
+}
+
+export function three() {
+    type Z = string;
+    return {} as Z;
+}
+//// [variables.js] ////
+const x = "";
+export function one() {
+    return {};
+}
+export function two() {
+    const y = "";
+    return {};
+}
+export function three() {
+    return {};
+}

tests/cases/fourslash/codeFixMissingTypeAnnotationOnExports49-private-name.ts

@@ -0,0 +1,48 @@
+/// <reference path='fourslash.ts'/>
+
+// @isolatedDeclarations: true
+// @declaration: true
+// @moduleResolution: node
+// @target: es2018
+// @jsx: react-jsx
+
+////export function two() {
+////    const y = "";
+////    return {} as typeof y;
+////}
+////
+////export function three() {
+////    type Z = string;
+////    return {} as Z;
+////}
+
+verify.codeFix({
+    description: "Add return type '\"\"'",
+    index: 0,
+    newFileContent:
+`export function two(): "" {
+    const y = "";
+    return {} as typeof y;
+}
+
+export function three() {
+    type Z = string;
+    return {} as Z;
+}`,
+});
+
+
+verify.codeFix({
+    description: "Add return type 'string'",
+    index: 1,
+    newFileContent:
+`export function two() {
+    const y = "";
+    return {} as typeof y;
+}
+
+export function three(): string {
+    type Z = string;
+    return {} as Z;
+}`,
+});

tests/cases/transpile/declarationNotInScopeTypes.ts

@@ -0,0 +1,17 @@
+// @declaration: true
+// @target: es6
+// @filename: variables.ts
+const x = "";
+export function one() {
+    return {} as typeof x;
+}
+
+export function two() {
+    const y = "";
+    return {} as typeof y;
+}
+
+export function three() {
+    type Z = string;
+    return {} as Z;
+}