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.

Author: blickly

tests/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;
+}`,
+});

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;
+}`,
+});