IRGen: Ignore the metadata of fixed sized types with opaque result type parameters

The removed check by this patch seems somewhat arbitrary and the test case that
was added for it no longer fails.

rdar://67841860

Author: aschwaighofer

lib/IRGen/Outlining.cpp

@@ -39,7 +39,6 @@ void OutliningMetadataCollector::collectTypeMetadataForLayout(SILType type) {
   }
 
   // Substitute opaque types if allowed.
-  auto origType = type;
   type =
       IGF.IGM.substOpaqueTypesWithUnderlyingTypes(type, CanGenericSignature());
 
@@ -49,9 +48,7 @@ void OutliningMetadataCollector::collectTypeMetadataForLayout(SILType type) {
   // We don't need the metadata for fixed size types or types that are not ABI
   // accessible. Outlining will call the value witness of the enclosing type of
   // non ABI accessible field/element types.
-  if ((!origType.getASTType()->hasOpaqueArchetype() &&
-       isa<FixedTypeInfo>(ti)) ||
-      !ti.isABIAccessible()) {
+  if (isa<FixedTypeInfo>(ti) || !ti.isABIAccessible()) {
     return;
   }
 

test/IRGen/Inputs/opaque_result_type_private_underlying_2.swift

@@ -45,3 +45,39 @@ public struct PublicUnderlyingInlinable : A {
     return PublicS()
   }
 }
+
+
+public protocol P {}
+
+private struct PrivateSome : P {}
+public func getSome() -> some P {
+  return PrivateSome()
+}
+
+@propertyWrapper
+public struct Wrapper<T> {
+  public var wrappedValue: T
+
+  public init(wrappedValue v: T) {
+    wrappedValue = v
+  }
+}
+
+public struct R<V, T: P>: P {
+  @Wrapper private var privateState = PrivateState()
+  var x: T? = nil
+
+  public init(_ v: V.Type, _ t: T) {
+    x = t
+  }
+
+  public mutating func modify() {
+    x = nil
+  }
+}
+
+private extension R {
+  struct PrivateState {
+    var x = 0
+  }
+}

test/IRGen/opaque_result_type_private_underlying.swift

@@ -68,3 +68,11 @@ public struct MyThing {
     }
 }
 #endif
+
+public struct E<V> {
+   var body : some P {
+     var r = R(V.self, getSome())
+     r.modify()
+     return r
+   }
+}