Merge pull request #71571 from xedin/copyable-fixes-for-variadics

[AST] Handle pack element types in `LookupConformanceInModuleRequest`

Author: xedin

lib/AST/ConformanceLookup.cpp

@@ -477,6 +477,11 @@ LookupConformanceInModuleRequest::evaluate(
   if (auto selfType = type->getAs<DynamicSelfType>())
     type = selfType->getSelfType();
 
+  // A pack element type conforms to whatever its underlying pack type
+  // conforms to.
+  if (auto packElement = type->getAs<PackElementType>())
+    type = packElement->getPackType();
+
   // An archetype conforms to a protocol if the protocol is listed in the
   // archetype's list of conformances, or if the archetype has a superclass
   // constraint and the superclass conforms to the protocol.

lib/Sema/CSSimplify.cpp

@@ -8492,18 +8492,23 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyConformsToConstraint(
     return SolutionKind::Solved;
   }
 
-  // Copyable is checked structurally, so for better performance, split apart
-  // this constraint into individual Copyable constraints on each tuple element.
-  if (auto *tupleType = type->getAs<TupleType>()) {
-    if (protocol->isSpecificProtocol(KnownProtocolKind::Copyable)) {
-      for (unsigned i = 0, e = tupleType->getNumElements(); i < e; ++i) {
-        addConstraint(ConstraintKind::ConformsTo,
-                      tupleType->getElementType(i),
-                      protocol->getDeclaredInterfaceType(),
-                      locator.withPathElement(LocatorPathElt::TupleElement(i)));
-      }
+  // FIXME: This is already handled by tuple conformance lookup path and
+  // should be removed once non-copyable generics are enabled by default.
+  if (!SWIFT_ENABLE_EXPERIMENTAL_NONCOPYABLE_GENERICS) {
+    // Copyable is checked structurally, so for better performance, split apart
+    // this constraint into individual Copyable constraints on each tuple
+    // element.
+    if (auto *tupleType = type->getAs<TupleType>()) {
+      if (protocol->isSpecificProtocol(KnownProtocolKind::Copyable)) {
+        for (unsigned i = 0, e = tupleType->getNumElements(); i < e; ++i) {
+          addConstraint(
+              ConstraintKind::ConformsTo, tupleType->getElementType(i),
+              protocol->getDeclaredInterfaceType(),
+              locator.withPathElement(LocatorPathElt::TupleElement(i)));
+        }
 
-      return SolutionKind::Solved;
+        return SolutionKind::Solved;
+      }
     }
   }