Fixed crash on authored import type nodes when serializing for declarations

src/services/codefixes/helpers.ts

@@ -899,6 +899,12 @@ export function tryGetAutoImportableReferenceFromTypeNode(importTypeNode: TypeNo
         if (isLiteralImportTypeNode(node) && node.qualifier) {
             // Symbol for the left-most thing after the dot
             const firstIdentifier = getFirstIdentifier(node.qualifier);
+            if (!firstIdentifier.symbol) {
+                // if symbol is missing then this doesn't come from a synthesized import type node
+                // it has to be an import type node authored by the user and thus it has to be valid
+                // it can't refer to reserved internal symbol names and such
+                return visitEachChild(node, visit, /*context*/ undefined);
+            }
             const name = getNameForExportedSymbol(firstIdentifier.symbol, scriptTarget);
             const qualifier = name !== firstIdentifier.text
                 ? replaceFirstIdentifierOfEntityName(node.qualifier, factory.createIdentifier(name))

tests/cases/fourslash/completionsClassMemberImportTypeNodeParameter1.ts

@@ -0,0 +1,34 @@
+/// <reference path="fourslash.ts" />
+
+// @module: nodenext
+
+// @Filename: /generation.d.ts
+//// export type GenerationConfigType = { max_length?: number };
+
+// @FileName: /index.d.ts
+//// export declare class PreTrainedModel {
+////   _get_generation_config(
+////     param: import("./generation.js").GenerationConfigType,
+////   ): import("./generation.js").GenerationConfigType;
+//// }
+////
+//// export declare class BlenderbotSmallPreTrainedModel extends PreTrainedModel {
+////   /*1*/
+//// }
+
+verify.completions({
+  marker: "1",
+  includes: [
+    {
+      name: "_get_generation_config",
+      insertText: `_get_generation_config(param: import("./generation.js").GenerationConfigType): import("./generation.js").GenerationConfigType;`,
+      filterText: "_get_generation_config",
+      hasAction: undefined,
+    },
+  ],
+  preferences: {
+    includeCompletionsWithClassMemberSnippets: true,
+    includeCompletionsWithInsertText: true,
+  },
+  isNewIdentifierLocation: true,
+});

tests/cases/fourslash/completionsClassMemberImportTypeNodeParameter2.ts

@@ -0,0 +1,31 @@
+/// <reference path="fourslash.ts" />
+
+// @module: nodenext
+
+// @FileName: /index.d.ts
+//// export declare class Cls {
+////   method(
+////     param: import("./doesntexist.js").Foo,
+////   ): import("./doesntexist.js").Foo;
+//// }
+////
+//// export declare class Derived extends Cls {
+////   /*1*/
+//// }
+
+verify.completions({
+  marker: "1",
+  includes: [
+    {
+      name: "method",
+      insertText: `method(param: import("./doesntexist.js").Foo);`,
+      filterText: "method",
+      hasAction: undefined,
+    },
+  ],
+  preferences: {
+    includeCompletionsWithClassMemberSnippets: true,
+    includeCompletionsWithInsertText: true,
+  },
+  isNewIdentifierLocation: true,
+});

tests/cases/fourslash/completionsClassMemberImportTypeNodeParameter3.ts

@@ -0,0 +1,37 @@
+/// <reference path="fourslash.ts" />
+
+// @module: nodenext
+
+// @FileName: /other/foo.d.ts
+//// export declare type Bar = { baz: string };
+
+// @FileName: /other/cls.d.ts
+//// export declare class Cls {
+////   method(
+////     param: import("./foo.js").Bar,
+////   ): import("./foo.js").Bar;
+//// }
+
+// @FileName: /index.d.ts
+//// import { Cls } from "./other/cls.js";
+////
+//// export declare class Derived extends Cls {
+////   /*1*/
+//// }
+
+verify.completions({
+  marker: "1",
+  includes: [
+    {
+      name: "method",
+      insertText: `method(param: import("./other/foo.js").Bar): import("./other/foo.js").Bar;`,
+      filterText: "method",
+      hasAction: undefined,
+    },
+  ],
+  preferences: {
+    includeCompletionsWithClassMemberSnippets: true,
+    includeCompletionsWithInsertText: true,
+  },
+  isNewIdentifierLocation: true,
+});

tests/cases/fourslash/completionsClassMemberImportTypeNodeParameter4.ts

@@ -0,0 +1,34 @@
+/// <reference path="fourslash.ts" />
+
+// @module: nodenext
+
+// @FileName: /other/cls.d.ts
+//// export declare class Cls {
+////   method(
+////     param: import("./doesntexist.js").Foo,
+////   ): import("./doesntexist.js").Foo;
+//// }
+
+// @FileName: /index.d.ts
+//// import { Cls } from "./other/cls.js";
+////
+//// export declare class Derived extends Cls {
+////   /*1*/
+//// }
+
+verify.completions({
+  marker: "1",
+  includes: [
+    {
+      name: "method",
+      insertText: `method(param: import("./doesntexist.js").Foo);`,
+      filterText: "method",
+      hasAction: undefined,
+    },
+  ],
+  preferences: {
+    includeCompletionsWithClassMemberSnippets: true,
+    includeCompletionsWithInsertText: true,
+  },
+  isNewIdentifierLocation: true,
+});