[CSSimplify] Don't attempt to destructure tuples to check for Copyable when non-copyable generics feature is enabled

Author: xedin

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;
+      }
     }
   }