Avoid including defaulted type arguments

Gerrit0 · Gerrit0 · commit 53fa22e577e1 · 2024-12-25T16:27:33.000-07:00
Resolves #2820
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -8,6 +8,7 @@ title: Changelog
 
 -   `@include` and `@includeCode` now work in the readme file, #2814.
 -   TypeDoc will now avoid making references to references, #2811.
+-   Improved type reference conversion to avoid including defaulted type arguments, #2820.
 -   Improved link resolution logic to prioritize type alias properties with the
     same symbol over type literal properties within function parameters.
 
diff --git a/src/lib/converter/types.ts b/src/lib/converter/types.ts
@@ -38,7 +38,7 @@ import {
     createSignature,
 } from "./factories/signature.js";
 import { convertSymbol } from "./symbols.js";
-import { isObjectType } from "./utils/nodes.js";
+import { isObjectType, isTypeReference } from "./utils/nodes.js";
 import { removeUndefined } from "./utils/reflections.js";
 import type { TranslatedString } from "../internationalization/internationalization.js";
 
@@ -813,6 +813,7 @@ const referenceConverter: TypeConverter<
             context,
             name,
         );
+
         if (type.flags & ts.TypeFlags.Substitution) {
             // NoInfer<T>
             ref.typeArguments = [
@@ -823,11 +824,24 @@ const referenceConverter: TypeConverter<
                 convertType(context, (type as ts.StringMappingType).type),
             ];
         } else {
-            ref.typeArguments = (
-                type.aliasSymbol
-                    ? type.aliasTypeArguments
-                    : (type as ts.TypeReference).typeArguments
-            )?.map((ref) => convertType(context, ref));
+            // Default type arguments are filled with a reference to the default
+            // type. As TS doesn't support specifying earlier defaults, we know
+            // that this will only filter out type arguments which aren't specified
+            // by the user.
+            let ignoredArgs: ts.Type[] | undefined;
+            if (isTypeReference(type)) {
+                ignoredArgs = type.target.typeParameters
+                    ?.map((p) => p.getDefault())
+                    .filter((x) => !!x);
+            }
+
+            const args = type.aliasSymbol
+                ? type.aliasTypeArguments
+                : (type as ts.TypeReference).typeArguments;
+
+            ref.typeArguments = args
+                ?.filter((ref) => !ignoredArgs?.includes(ref))
+                .map((ref) => convertType(context, ref));
         }
         return ref;
     },
diff --git a/src/lib/converter/utils/nodes.ts b/src/lib/converter/utils/nodes.ts
@@ -37,3 +37,10 @@ export function getHeritageTypes(
 export function isObjectType(type: ts.Type): type is ts.ObjectType {
     return typeof (type as any).objectFlags === "number";
 }
+
+export function isTypeReference(type: ts.Type): type is ts.TypeReference {
+    return (
+        isObjectType(type) &&
+        (type.objectFlags & ts.ObjectFlags.Reference) !== 0
+    );
+}
diff --git a/src/test/converter/function/specs.json b/src/test/converter/function/specs.json
@@ -547,14 +547,6 @@
                         "name": "T",
                         "package": "typedoc",
                         "refersToTypeParameter": true
-                      },
-                      {
-                        "type": "intrinsic",
-                        "name": "any"
-                      },
-                      {
-                        "type": "intrinsic",
-                        "name": "any"
                       }
                     ],
                     "name": "Iterable",
@@ -705,14 +697,6 @@
                                 "name": "T",
                                 "package": "typedoc",
                                 "refersToTypeParameter": true
-                              },
-                              {
-                                "type": "intrinsic",
-                                "name": "any"
-                              },
-                              {
-                                "type": "intrinsic",
-                                "name": "any"
                               }
                             ],
                             "name": "Iterable",
diff --git a/src/test/converter2/issues/gh2820.ts b/src/test/converter2/issues/gh2820.ts
@@ -0,0 +1,3 @@
+export function f(a: Uint8Array): Uint8Array {
+    return a;
+}
diff --git a/src/test/issues.c2.test.ts b/src/test/issues.c2.test.ts
@@ -1983,4 +1983,12 @@ describe("Issue Tests", () => {
         ok(rename2.isReference());
         ok(rename2.getTargetReflection() === abc);
     });
+
+    it("#2820 does not include defaulted type arguments", () => {
+        const project = convert();
+        const f = querySig(project, "f");
+
+        equal(f.type?.toString(), "Uint8Array");
+        equal(f.parameters?.[0].type?.toString(), "Uint8Array");
+    });
 });

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+export function f(a: Uint8Array): Uint8Array {`
	`2`	`+ return a;`
	`3`	`+}`