Make the implicitly exported rule consistent between checker and binder (#54659)

src/compiler/binder.ts

@@ -87,6 +87,7 @@ import {
     getElementOrPropertyAccessName,
     getEmitScriptTarget,
     getEnclosingBlockScopeContainer,
+    getEnclosingContainer,
     getErrorSpanForNode,
     getEscapedTextOfIdentifierOrLiteral,
     getEscapedTextOfJsxNamespacedName,
@@ -455,7 +456,8 @@ function getModuleInstanceStateForAliasTarget(specifier: ExportSpecifier, visite
     return ModuleInstanceState.Instantiated; // Couldn't locate, assume could refer to a value
 }
 
-const enum ContainerFlags {
+/** @internal */
+export const enum ContainerFlags {
     // The current node is not a container, and no container manipulation should happen before
     // recursing into it.
     None = 0,
@@ -2356,7 +2358,7 @@ function createBinder(): (file: SourceFile, options: CompilerOptions) => void {
         const saveCurrentFlow = currentFlow;
         for (const typeAlias of delayedTypeAliases) {
             const host = typeAlias.parent.parent;
-            container = (findAncestor(host.parent, n => !!(getContainerFlags(n) & ContainerFlags.IsContainer)) as IsContainer | undefined) || file;
+            container = (getEnclosingContainer(host) as IsContainer | undefined) || file;
             blockScopeContainer = (getEnclosingBlockScopeContainer(host) as IsBlockScopedContainer | undefined) || file;
             currentFlow = initFlowNode({ flags: FlowFlags.Start });
             parent = typeAlias;
@@ -3768,7 +3770,8 @@ export function isExportsOrModuleExportsOrAlias(sourceFile: SourceFile, node: Ex
     return false;
 }
 
-function getContainerFlags(node: Node): ContainerFlags {
+/** @internal */
+export function getContainerFlags(node: Node): ContainerFlags {
     switch (node.kind) {
         case SyntaxKind.ClassExpression:
         case SyntaxKind.ClassDeclaration:

src/compiler/checker.ts

@@ -274,6 +274,7 @@ import {
     getEmitModuleResolutionKind,
     getEmitScriptTarget,
     getEnclosingBlockScopeContainer,
+    getEnclosingContainer,
     getEntityNameFromTypeNode,
     getErrorSpanForNode,
     getEscapedTextOfIdentifierOrLiteral,
@@ -39038,8 +39039,9 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             n.parent.kind !== SyntaxKind.ClassDeclaration &&
             n.parent.kind !== SyntaxKind.ClassExpression &&
             n.flags & NodeFlags.Ambient) {
-            if (!(flags & ModifierFlags.Ambient) && !(isModuleBlock(n.parent) && isModuleDeclaration(n.parent.parent) && isGlobalScopeAugmentation(n.parent.parent))) {
-                // It is nested in an ambient context, which means it is automatically exported
+            const container = getEnclosingContainer(n);
+            if ((container && container.flags & NodeFlags.ExportContext) && !(flags & ModifierFlags.Ambient) && !(isModuleBlock(n.parent) && isModuleDeclaration(n.parent.parent) && isGlobalScopeAugmentation(n.parent.parent))) {
+                // It is nested in an ambient export context, which means it is automatically exported
                 flags |= ModifierFlags.Export;
             }
             flags |= ModifierFlags.Ambient;

src/compiler/utilities.ts

@@ -73,6 +73,7 @@ import {
     ConditionalExpression,
     ConstructorDeclaration,
     ConstructSignatureDeclaration,
+    ContainerFlags,
     contains,
     containsPath,
     createGetCanonicalFileName,
@@ -162,6 +163,7 @@ import {
     GetCanonicalFileName,
     getCombinedModifierFlags,
     getCombinedNodeFlags,
+    getContainerFlags,
     getDirectoryPath,
     getJSDocAugmentsTag,
     getJSDocDeprecatedTagNoCache,
@@ -2022,6 +2024,11 @@ export function isAnyImportOrReExport(node: Node): node is AnyImportOrReExport {
     return isAnyImportSyntax(node) || isExportDeclaration(node);
 }
 
+/** @internal */
+export function getEnclosingContainer(node: Node): Node | undefined {
+    return findAncestor(node.parent, n => !!(getContainerFlags(n) & ContainerFlags.IsContainer));
+}
+
 // Gets the nearest enclosing block scope container that has the provided node
 // as a descendant, that is not the provided node.
 /** @internal */