Disable mangling of inverses for generalized existential shape symbols

Author: DougGregor

lib/IRGen/IRGenMangler.cpp

@@ -495,7 +495,11 @@ void
 IRGenMangler::appendExtendedExistentialTypeShape(CanGenericSignature genSig,
                                                  CanType shapeType) {
   // Append the generalization signature.
-  if (genSig) appendGenericSignature(genSig);
+  if (genSig) {
+    // Generalization signature never reference inverses.
+    llvm::SaveAndRestore X(AllowInverses, false);
+    appendGenericSignature(genSig);
+  }
 
   // Append the existential type.
   appendType(shapeType, genSig);

test/IRGen/existential_shape_metadata.swift

@@ -1,7 +1,5 @@
 // RUN: %target-swift-frontend -emit-ir %s -swift-version 5 -disable-availability-checking | %IRGenFileCheck %s
 
-// XFAIL: noncopyable_generics
-
 // CHECK-LABEL: @"$sl26existential_shape_metadata2Q0_px1TRts_XPXGMq" = linkonce_odr hidden constant
 // CHECK-SAME:  { i32 {{.*}}sub ([[INT]] ptrtoint (ptr @{{[0-9]+}} to [[INT]])
 // CHECK-SAME:    i32 6400,

test/IRGen/existential_shape_metadata_noncopyable.swift

@@ -0,0 +1,16 @@
+// RUN: %target-swift-frontend -emit-ir %s -swift-version 5 -disable-availability-checking -enable-experimental-feature NoncopyableGenerics -module-name existential_shape_metadata | %IRGenFileCheck %s
+
+// NOTE: Once noncopyable generics are enabled by default, merge this back into existential_shape_metadata.swift
+
+// CHECK: @"$sl26existential_shape_metadata3QNC_px1ARts_XPXGMq" = linkonce_odr
+
+public protocol QNC<A>: ~Copyable {
+  associatedtype A: ~Copyable
+}
+
+public struct NCStruct: ~Copyable { }
+
+
+public func testNoncopyableConcrete() -> (Any & ~Copyable).Type {
+  return (any QNC<NCStruct>).self
+}