Add a few more test cases of the "negative" cases

These are the cases where our heuristic makes some compromise that isn't what we would have preferred, but add the unit tests as a way of documenting the current behavior.
microsoft · jakebailey · Sep 16, 2024 · Jul 25, 2024 · Aug 8, 2024 · Aug 8, 2024
commit b0bc68fcabd64d09ac7020446d670d56234a97b5
diff --git a/...s/cases/fourslash/codeFixMissingTypeAnnotationOnExports52-gerenrics-oversimplification.ts b/...s/cases/fourslash/codeFixMissingTypeAnnotationOnExports52-gerenrics-oversimplification.ts
@@ -0,0 +1,23 @@
+/// <reference path='fourslash.ts'/>
+
+// In the abstract, we might prefer the inferred return type annotation to
+// be identical to the parameter type (with 2 type parameters).
+// Our current heursitic to avoid overly complex types in this case creates
+// "overly simple" types, but this tradeoff seems reasonable.
+
+// @isolatedDeclarations: true
+// @declaration: true
+////export interface Foo<T, U = T[]> {}
+////export function foo(x: Foo<string, string[]>) {
+////    return x;
+////}
+
+verify.codeFix({
+    description: "Add return type 'Foo<string>'",
+    index: 0,
+    newFileContent:
+`export interface Foo<T, U = T[]> {}
+export function foo(x: Foo<string, string[]>): Foo<string> {
+    return x;
+}`,
+});
diff --git a/tests/cases/fourslash/codeFixMissingTypeAnnotationOnExports53-nested-generic-types.ts b/tests/cases/fourslash/codeFixMissingTypeAnnotationOnExports53-nested-generic-types.ts
@@ -0,0 +1,21 @@
+/// <reference path='fourslash.ts'/>
+
+// Our current heursitic to avoid overly verbose generic types
+// doesn't handle generic types nested inside other types.
+
+// @isolatedDeclarations: true
+// @declaration: true
+////export interface Foo<T, U = T[]> {}
+////export function foo(x: Map<number, Foo<string>>) {
+////    return x;
+////}
+
+verify.codeFix({
+    description: "Add return type 'Map<number, Foo<string, string[]>>'",
+    index: 0,
+    newFileContent:
+`export interface Foo<T, U = T[]> {}
+export function foo(x: Map<number, Foo<string>>): Map<number, Foo<string, string[]>> {
+    return x;
+}`,
+});