[SIL] Only lexical owned args are lexical.

Previously, every owned argument was considered lexical.  That included
owned arguments with eager move lifetimes.  Here, only owned arguments
whose lifetimes are lexical (i.e. not those whose lifetimes are eager
move) are considered lexical.

Author: nate-chandler

lib/SIL/IR/SILValue.cpp

@@ -106,8 +106,11 @@ ValueBase::getDefiningInstructionResult() {
 }
 
 bool ValueBase::isLexical() const {
-  if (auto *argument = dyn_cast<SILFunctionArgument>(this))
-    return argument->getOwnershipKind() == OwnershipKind::Owned;
+  if (auto *argument = dyn_cast<SILFunctionArgument>(this)) {
+    // TODO: Recognize guaranteed arguments as lexical too.
+    return argument->getOwnershipKind() == OwnershipKind::Owned &&
+           argument->getLifetime().isLexical();
+  }
   if (auto *bbi = dyn_cast<BeginBorrowInst>(this))
     return bbi->isLexical();
   if (auto *mvi = dyn_cast<MoveValueInst>(this))