Merge pull request #61346 from slavapestov/test-case-for-protocol-extension-where-clause-typealias

Add missing test case

Author: slavapestov

test/Generics/protocol_extension_where_clause.swift

@@ -0,0 +1,23 @@
+// RUN: %target-typecheck-verify-swift %s
+
+protocol P<T> {
+  associatedtype T
+}
+
+extension P {
+  typealias A = Int
+  // expected-note@-1 3{{consider moving 'A' into the definition of protocol 'P'}}
+}
+
+protocol Q {
+  associatedtype T: P
+  associatedtype U: P<T.A>
+  // expected-error@-1 {{'A' was defined in extension of protocol 'P' and cannot be referenced from a associated type inheritance clause}}
+}
+
+struct S<T: P, U: P<T.A>> {
+  // expected-error@-1 {{'A' was defined in extension of protocol 'P' and cannot be referenced from a generic parameter inheritance clause}}
+
+  func f<V>(_: V) where V == T.A {}
+  // expected-error@-1 {{'A' was defined in extension of protocol 'P' and cannot be referenced from a 'where' clause}}
+}