Fix tests

Author: angela-laar

test/Constraints/opened_existentials.swift

@@ -311,15 +311,15 @@ class C1 {}
 class C2<T>: C1 {}
 
 // Protocols With Associated Types
-protocol Q {
+protocol T {
   associatedtype A
   associatedtype B: C2<A>
 
   func returnAssocTypeB() -> B
 }
 
-func testAssocReturn(p: any Q) {
-  let _ = p.returnAssocTypeB() // expected-error {{inferred result type 'C2<(any U<String>).A>' requires explicit coercion due to loss of generic requirements}} {{14-14=as as C2<(any Q).A>}}
+func testAssocReturn(p: any T) {
+  let _ = p.returnAssocTypeB() // expected-error {{inferred result type 'C2<(any T).A>' requires explicit coercion due to loss of generic requirements}} {{29-29=as C2<(any T).A>}}
 }
 
 // Protocols With Primary Associated Types
@@ -333,13 +333,14 @@ protocol U<A> {
 }
 
 func testPrimaryAssocReturn(p: any U<String>) {
-  let _ = p.returnAssocTypeB()
+  let _ = p.returnAssocTypeB() // expected-error {{inferred result type 'C2<(any U<String>).A>' requires explicit coercion due to loss of generic requirements}} {{29-29=as C2<(any U<String>).A>}}
 }
 
 func testPrimaryAssocReturn(p: any U<Int>) {
-  let _ = p.returnPrimaryAssocTypeA() // what would the output even be here?
+  let _ = p.returnPrimaryAssocTypeA()
 }
 
+@available
 func testPrimaryAssocCollection(p: any U<Float>) -> any Collection {
   let x = p.returnAssocTypeCollection()
   return x