Merge pull request #80746 from drexin/wip-149007227

[IRGen] Set generic context before getting call emission in visitFull…

Author: drexin

lib/IRGen/IRGenSIL.cpp

@@ -3861,6 +3861,10 @@ void IRGenSILFunction::visitFullApplySite(FullApplySite site) {
     }
   }
 
+  // Lower the arguments and return value in the callee's generic context.
+  GenericContextScope scope(IGM,
+                            origCalleeType->getInvocationGenericSignature());
+
   Explosion llArgs;
   WitnessMetadata witnessMetadata;
   auto emission = getCallEmissionForLoweredValue(
@@ -3873,9 +3877,6 @@ void IRGenSILFunction::visitFullApplySite(FullApplySite site) {
 
   emission->begin();
 
-  // Lower the arguments and return value in the callee's generic context.
-  GenericContextScope scope(IGM, origCalleeType->getInvocationGenericSignature());
-
   auto &calleeFP = emission->getCallee().getFunctionPointer();
 
   // Allocate space for the coroutine buffer.

test/IRGen/typed_throws.swift

@@ -359,3 +359,15 @@ struct SomeStruct {
 func someFunc() async throws(SmallError) -> SomeStruct {
     SomeStruct(x: 42, y: 23, z: 25)
 }
+
+// Used to crash the compiler -- https://github.com/swiftlang/swift/issues/80732
+protocol PAssoc<T>: AnyObject {
+    associatedtype T
+    func foo() async throws(SmallError) -> (any PAssoc<T>)
+}
+
+class MyProtocolImpl<T>: PAssoc {
+    func foo() async throws(SmallError) -> (any PAssoc<T>) {
+        fatalError()
+    }
+}