canonicalize before matching on a type in isPureMoveOnly

Author: kavon

lib/AST/Type.cpp

@@ -170,7 +170,7 @@ bool TypeBase::isPureMoveOnly() {
     return nom->isMoveOnly();
 
   // if any components of the tuple are move-only, then the tuple is move-only.
-  if (auto *tupl = getAs<TupleType>()) {
+  if (auto *tupl = getCanonicalType()->getAs<TupleType>()) {
     for (auto eltTy : tupl->getElementTypes())
       if (eltTy->isPureMoveOnly())
         return true;