Index: lib/TableGen/Record.cpp
===================================================================
--- lib/TableGen/Record.cpp
+++ lib/TableGen/Record.cpp
@@ -764,7 +764,7 @@
   if (LHS != lhs)
     return (UnOpInit::get(getOpcode(), lhs, getType()))
         ->Fold(R.getCurrentRecord());
-  return Fold(R.getCurrentRecord());
+  return const_cast<UnOpInit *>(this);
 }
 
 std::string UnOpInit::getAsString() const {
@@ -947,7 +947,7 @@
   if (LHS != lhs || RHS != rhs)
     return (BinOpInit::get(getOpcode(), lhs, rhs, getType()))
         ->Fold(R.getCurrentRecord());
-  return Fold(R.getCurrentRecord());
+  return const_cast<BinOpInit *>(this);
 }
 
 std::string BinOpInit::getAsString() const {
@@ -1172,7 +1172,7 @@
   if (LHS != lhs || MHS != mhs || RHS != rhs)
     return (TernOpInit::get(getOpcode(), lhs, mhs, rhs, getType()))
         ->Fold(R.getCurrentRecord());
-  return Fold(R.getCurrentRecord());
+  return const_cast<TernOpInit *>(this);
 }
 
 std::string TernOpInit::getAsString() const {
Index: lib/TableGen/TGParser.cpp
===================================================================
--- lib/TableGen/TGParser.cpp
+++ lib/TableGen/TGParser.cpp
@@ -1960,7 +1960,13 @@
       }
 
       if (LHS->getType() != StringRecTy::get()) {
-        LHS = UnOpInit::get(UnOpInit::CAST, LHS, StringRecTy::get());
+        LHS = dyn_cast<TypedInit>(
+            UnOpInit::get(UnOpInit::CAST, LHS, StringRecTy::get())
+                ->Fold(CurRec));
+        if (!LHS) {
+          Error(PasteLoc, "LHS of paste not typed after cast!");
+          return nullptr;
+        }
       }
 
       TypedInit *RHS = nullptr;
@@ -1987,7 +1993,13 @@
         }
 
         if (RHS->getType() != StringRecTy::get()) {
-          RHS = UnOpInit::get(UnOpInit::CAST, RHS, StringRecTy::get());
+          RHS = dyn_cast<TypedInit>(
+              UnOpInit::get(UnOpInit::CAST, RHS, StringRecTy::get())
+                  ->Fold(CurRec));
+          if (!RHS) {
+            Error(PasteLoc, "RHS of paste not typed after cast!");
+            return nullptr;
+          }
         }
 
         break;