fix: Correct handling of arrays in generic constraints

Closes #1408

Author: Gerrit0

scripts/rebuild_specs.js

@@ -58,29 +58,26 @@ function rebuildConverterTests(dirs) {
         return;
     }
 
-    return Promise.all(
-        dirs.map((fullPath) => {
-            console.log(fullPath);
-            const src = app.expandInputFiles([fullPath]);
-            return Promise.all(
-                conversions.map(([file, before, after]) => {
-                    const out = path.join(fullPath, `${file}.json`);
-                    if (fs.existsSync(out)) {
-                        TypeDoc.resetReflectionID();
-                        before();
-                        const result = app.converter.convert(src, program);
-                        const serialized = app.serializer.toObject(result);
-
-                        const data = JSON.stringify(serialized, null, "  ")
-                            .split(TypeDoc.normalizePath(base))
-                            .join("%BASE%");
-                        after();
-                        return fs.writeFile(out.replace("dist", "src"), data);
-                    }
-                })
-            );
-        })
-    );
+    for (const fullPath of dirs) {
+        console.log(fullPath);
+        const src = app.expandInputFiles([fullPath]);
+
+        for (const [file, before, after] of conversions) {
+            const out = path.join(fullPath, `${file}.json`);
+            if (fs.existsSync(out)) {
+                TypeDoc.resetReflectionID();
+                before();
+                const result = app.converter.convert(src, program);
+                const serialized = app.serializer.toObject(result);
+
+                const data = JSON.stringify(serialized, null, "  ")
+                    .split(TypeDoc.normalizePath(base))
+                    .join("%BASE%");
+                after();
+                fs.writeFileSync(out.replace("dist", "src"), data);
+            }
+        }
+    }
 }
 
 async function rebuildRendererTest() {

src/lib/converter/types.ts

@@ -149,7 +149,9 @@ const arrayConverter: TypeConverter<ts.ArrayTypeNode, ts.TypeReference> = {
     },
     convertType(context, type) {
         const params = context.checker.getTypeArguments(type);
-        assert(params.length === 1);
+        // This is *almost* always true... except for when this type is in the constraint of a type parameter see GH#1408
+        // assert(params.length === 1);
+        assert(params.length > 0);
         return new ArrayType(convertType(context, params[0]));
     },
 };

src/test/converter/alias/alias.ts

@@ -61,3 +61,7 @@ export namespace GH1330 {
     declare const makeProp: <T>(x: T) => HasProp<T>;
     export const testValue3 = makeProp(1);
 }
+
+export namespace GH1408 {
+    export declare function foo<T extends unknown[]>(): T;
+}

src/test/converter/alias/specs.json

@@ -177,6 +177,60 @@
         }
       ]
     },
+    {
+      "id": 39,
+      "name": "GH1408",
+      "kind": 2,
+      "kindString": "Namespace",
+      "flags": {},
+      "children": [
+        {
+          "id": 40,
+          "name": "foo",
+          "kind": 64,
+          "kindString": "Function",
+          "flags": {},
+          "signatures": [
+            {
+              "id": 41,
+              "name": "foo",
+              "kind": 4096,
+              "kindString": "Call signature",
+              "flags": {},
+              "typeParameter": [
+                {
+                  "id": 42,
+                  "name": "T",
+                  "kind": 131072,
+                  "kindString": "Type parameter",
+                  "flags": {},
+                  "type": {
+                    "type": "array",
+                    "elementType": {
+                      "type": "intrinsic",
+                      "name": "unknown"
+                    }
+                  }
+                }
+              ],
+              "type": {
+                "type": "reference",
+                "name": "T"
+              }
+            }
+          ]
+        }
+      ],
+      "groups": [
+        {
+          "title": "Functions",
+          "kind": 64,
+          "children": [
+            40
+          ]
+        }
+      ]
+    },
     {
       "id": 21,
       "name": "HorribleRecursiveTypeThatShouldNotBeUsedByAnyone",
@@ -684,7 +738,8 @@
       "title": "Namespaces",
       "kind": 2,
       "children": [
-        28
+        28,
+        39
       ]
     },
     {