For import completion, use an existing namespace import (#20457)

src/services/codefixes/importFixes.ts

@@ -30,7 +30,7 @@ namespace ts.codefix {
     }
 
     interface SymbolAndTokenContext extends SymbolContext {
-        symbolToken: Node | undefined;
+        symbolToken: Identifier | undefined;
     }
 
     interface ImportCodeFixContext extends SymbolAndTokenContext {
@@ -169,7 +169,8 @@ namespace ts.codefix {
         const useCaseSensitiveFileNames = context.host.useCaseSensitiveFileNames ? context.host.useCaseSensitiveFileNames() : false;
         const { program } = context;
         const checker = program.getTypeChecker();
-        const symbolToken = getTokenAtPosition(context.sourceFile, context.span.start, /*includeJsDocComment*/ false);
+        // This will always be an Identifier, since the diagnostics we fix only fail on identifiers.
+        const symbolToken = cast(getTokenAtPosition(context.sourceFile, context.span.start, /*includeJsDocComment*/ false), isIdentifier);
         return {
             host: context.host,
             newLineCharacter: context.newLineCharacter,
@@ -213,14 +214,17 @@ namespace ts.codefix {
             for (const declaration of declarations) {
                 const namespace = getNamespaceImportName(declaration);
                 if (namespace) {
-                    actions.push(getCodeActionForUseExistingNamespaceImport(namespace.text, context, context.symbolToken));
+                    const moduleSymbol = context.checker.getAliasedSymbol(context.checker.getSymbolAtLocation(namespace));
+                    if (moduleSymbol && moduleSymbol.exports.has(escapeLeadingUnderscores(context.symbolName))) {
+                        actions.push(getCodeActionForUseExistingNamespaceImport(namespace.text, context, context.symbolToken));
+                    }
                 }
             }
         }
         return [...actions, ...getCodeActionsForAddImport(moduleSymbols, context, declarations)];
     }
 
-    function getNamespaceImportName(declaration: AnyImportSyntax): Identifier {
+    function getNamespaceImportName(declaration: AnyImportSyntax): Identifier | undefined {
         if (declaration.kind === SyntaxKind.ImportDeclaration) {
             const namedBindings = declaration.importClause && isImportClause(declaration.importClause) && declaration.importClause.namedBindings;
             return namedBindings && namedBindings.kind === SyntaxKind.NamespaceImport ? namedBindings.name : undefined;
@@ -683,7 +687,7 @@ namespace ts.codefix {
         }
     }
 
-    function getCodeActionForUseExistingNamespaceImport(namespacePrefix: string, context: SymbolContext, symbolToken: Node): ImportCodeAction {
+    function getCodeActionForUseExistingNamespaceImport(namespacePrefix: string, context: SymbolContext, symbolToken: Identifier): ImportCodeAction {
         const { symbolName, sourceFile } = context;
 
         /**
@@ -696,13 +700,10 @@ namespace ts.codefix {
          * namespace instead of altering the import declaration. For example, "foo" would
          * become "ns.foo"
          */
-        return createCodeAction(
-            Diagnostics.Change_0_to_1,
-            [symbolName, `${namespacePrefix}.${symbolName}`],
-            ChangeTracker.with(context, tracker =>
-                tracker.replaceNode(sourceFile, symbolToken, createPropertyAccess(createIdentifier(namespacePrefix), symbolName))),
-            "CodeChange",
-            /*moduleSpecifier*/ undefined);
+        // Prefix the node instead of it replacing it, because this may be used for import completions and we don't want the text changes to overlap with the identifier being completed.
+        const changes = ChangeTracker.with(context, tracker =>
+            tracker.changeIdentifierToPropertyAccess(sourceFile, namespacePrefix, symbolToken));
+        return createCodeAction(Diagnostics.Change_0_to_1, [symbolName, `${namespacePrefix}.${symbolName}`], changes, "CodeChange", /*moduleSpecifier*/ undefined);
     }
 
     function getImportCodeActions(context: CodeFixContext): ImportCodeAction[] {

src/services/completions.ts

@@ -431,13 +431,13 @@ namespace ts.Completions {
         position: number,
         { name, source }: CompletionEntryIdentifier,
         allSourceFiles: ReadonlyArray<SourceFile>,
-    ): { type: "symbol", symbol: Symbol, location: Node, symbolToOriginInfoMap: SymbolOriginInfoMap } | { type: "request", request: Request } | { type: "none" } {
+    ): { type: "symbol", symbol: Symbol, location: Node, symbolToOriginInfoMap: SymbolOriginInfoMap, previousToken: Node } | { type: "request", request: Request } | { type: "none" } {
         const completionData = getCompletionData(typeChecker, log, sourceFile, position, allSourceFiles, { includeExternalModuleExports: true }, compilerOptions.target);
         if (!completionData) {
             return { type: "none" };
         }
 
-        const { symbols, location, allowStringLiteral, symbolToOriginInfoMap, request } = completionData;
+        const { symbols, location, allowStringLiteral, symbolToOriginInfoMap, request, previousToken } = completionData;
         if (request) {
             return { type: "request", request };
         }
@@ -451,7 +451,7 @@ namespace ts.Completions {
             return getCompletionEntryDisplayNameForSymbol(s, compilerOptions.target, /*performCharacterChecks*/ false, allowStringLiteral, origin) === name
                 && getSourceFromOrigin(origin) === source;
         });
-        return symbol ? { type: "symbol", symbol, location, symbolToOriginInfoMap } : { type: "none" };
+        return symbol ? { type: "symbol", symbol, location, symbolToOriginInfoMap, previousToken } : { type: "none" };
     }
 
     function getSymbolName(symbol: Symbol, origin: SymbolOriginInfo | undefined, target: ScriptTarget): string {
@@ -496,8 +496,8 @@ namespace ts.Completions {
                 }
             }
             case "symbol": {
-                const { symbol, location, symbolToOriginInfoMap } = symbolCompletion;
-                const { codeActions, sourceDisplay } = getCompletionEntryCodeActionsAndSourceDisplay(symbolToOriginInfoMap, symbol, program, typeChecker, host, compilerOptions, sourceFile, formatContext, getCanonicalFileName, allSourceFiles);
+                const { symbol, location, symbolToOriginInfoMap, previousToken } = symbolCompletion;
+                const { codeActions, sourceDisplay } = getCompletionEntryCodeActionsAndSourceDisplay(symbolToOriginInfoMap, symbol, program, typeChecker, host, compilerOptions, sourceFile, previousToken, formatContext, getCanonicalFileName, allSourceFiles);
                 const kindModifiers = SymbolDisplay.getSymbolModifiers(symbol);
                 const { displayParts, documentation, symbolKind, tags } = SymbolDisplay.getSymbolDisplayPartsDocumentationAndSymbolKind(typeChecker, symbol, sourceFile, location, location, SemanticMeaning.All);
                 return { name, kindModifiers, kind: symbolKind, displayParts, documentation, tags, codeActions, source: sourceDisplay };
@@ -529,6 +529,7 @@ namespace ts.Completions {
         host: LanguageServiceHost,
         compilerOptions: CompilerOptions,
         sourceFile: SourceFile,
+        previousToken: Node,
         formatContext: formatting.FormatContext,
         getCanonicalFileName: GetCanonicalFileName,
         allSourceFiles: ReadonlyArray<SourceFile>,
@@ -554,9 +555,9 @@ namespace ts.Completions {
             formatContext,
             symbolName: getSymbolName(symbol, symbolOriginInfo, compilerOptions.target),
             getCanonicalFileName,
-            symbolToken: undefined,
+            symbolToken: tryCast(previousToken, isIdentifier),
             kind: isDefaultExport ? codefix.ImportKind.Default : codefix.ImportKind.Named,
-        });
+        }).slice(0, 1); // Only take the first code action
         return { sourceDisplay, codeActions };
     }
 
@@ -597,6 +598,7 @@ namespace ts.Completions {
         keywordFilters: KeywordCompletionFilters;
         symbolToOriginInfoMap: SymbolOriginInfoMap;
         recommendedCompletion: Symbol | undefined;
+        previousToken: Node;
     }
     type Request = { kind: "JsDocTagName" } | { kind: "JsDocTag" } | { kind: "JsDocParameterName", tag: JSDocParameterTag };
 
@@ -709,6 +711,7 @@ namespace ts.Completions {
                     keywordFilters: KeywordCompletionFilters.None,
                     symbolToOriginInfoMap: undefined,
                     recommendedCompletion: undefined,
+                    previousToken: undefined,
                 };
             }
 
@@ -849,7 +852,7 @@ namespace ts.Completions {
         log("getCompletionData: Semantic work: " + (timestamp() - semanticStart));
 
         const recommendedCompletion = getRecommendedCompletion(previousToken, typeChecker);
-        return { symbols, isGlobalCompletion, isMemberCompletion, allowStringLiteral, isNewIdentifierLocation, location, isRightOfDot: (isRightOfDot || isRightOfOpenTag), request, keywordFilters, symbolToOriginInfoMap, recommendedCompletion };
+        return { symbols, isGlobalCompletion, isMemberCompletion, allowStringLiteral, isNewIdentifierLocation, location, isRightOfDot: (isRightOfDot || isRightOfOpenTag), request, keywordFilters, symbolToOriginInfoMap, recommendedCompletion, previousToken };
 
         type JSDocTagWithTypeExpression = JSDocParameterTag | JSDocPropertyTag | JSDocReturnTag | JSDocTypeTag | JSDocTypedefTag;
 

src/services/textChanges.ts

@@ -345,6 +345,11 @@ namespace ts.textChanges {
             return this.replaceWithSingle(sourceFile, startPosition, startPosition, newNode, this.getOptionsForInsertNodeBefore(before, blankLineBetween));
         }
 
+        public changeIdentifierToPropertyAccess(sourceFile: SourceFile, prefix: string, node: Identifier): void {
+            const startPosition = getAdjustedStartPosition(sourceFile, node, {}, Position.Start);
+            this.replaceWithSingle(sourceFile, startPosition, startPosition, createPropertyAccess(createIdentifier(prefix), ""), {});
+        }
+
         private getOptionsForInsertNodeBefore(before: Node, doubleNewlines: boolean): ChangeNodeOptions {
             if (isStatement(before) || isClassElement(before)) {
                 return { suffix: doubleNewlines ? this.newLineCharacter + this.newLineCharacter : this.newLineCharacter };

tests/cases/fourslash/completionsImport_named_namespaceImportExists.ts

@@ -16,9 +16,8 @@ verify.completionListContains({ name: "foo", source: "/a" }, "function foo(): vo
 verify.applyCodeActionFromCompletion("", {
     name: "foo",
     source: "/a",
-    description: `Import 'foo' from module "./a"`,
+    description: `Change 'foo' to 'a.foo'`,
     // TODO: GH#18445
     newFileContent: `import * as a from "./a";
-import { foo } from "./a";\r
-f;`,
+a.f;`,
 });

tests/cases/fourslash/importNameCodeFixDefaultExport1.ts

@@ -0,0 +1,13 @@
+/// <reference path="fourslash.ts" />
+
+// @Filename: /foo-bar.ts
+////export default function fooBar();
+
+// @Filename: /b.ts
+////[|import * as fb from "./foo-bar";
+////foo/**/Bar|]
+
+goTo.file("/b.ts");
+// No suggestion to use `fb.fooBar` (which would be wrong)
+verify.importFixAtPosition([`import fooBar, * as fb from "./foo-bar";
+fooBar`]);