diff --git a/Expression.pas b/Expression.pas
index 9a801d0..ec5228a 100644
--- a/Expression.pas
+++ b/Expression.pas
@@ -1058,6 +1058,10 @@ var
          op^.left := Pop;
          kindRight := op^.right^.token.kind;
          kindLeft := op^.left^.token.kind;
+         if not (kind in [normalExpression,autoInitializerExpression]) then
+            if (kindLeft in [longlongconst,ulonglongconst])
+               or (kindRight in [longlongconst,ulonglongconst]) then
+               Error(157);
          if kindRight in [intconst,uintconst,longconst,ulongconst] then begin
             if kindLeft in [intconst,uintconst,longconst,ulongconst] then begin
                if kind = preprocessorExpression then begin
@@ -1378,6 +1382,9 @@ var
          else if not (op^.token.kind in
             [typedef,plusplusop,minusminusop,opplusplus,opminusminus,uand]) then
             begin
+            if not (kind in [normalExpression,autoInitializerExpression]) then
+               if op^.left^.token.kind in [longlongconst,ulonglongconst] then
+                  Error(157);
             if (op^.left^.token.kind
                in [intconst,uintconst,longconst,ulongconst]) then begin
 
diff --git a/Scanner.pas b/Scanner.pas
index 96e807a..b5026cc 100644
--- a/Scanner.pas
+++ b/Scanner.pas
@@ -687,6 +687,7 @@ if list or (numErr <> 0) then begin
         154: msg := @'lint: function declared _Noreturn can return or has unreachable code';
         155: msg := @'lint: non-void function may not return a value or has unreachable code';
         156: msg := @'invalid suffix on numeric constant';
+        157: msg := @'ORCA/C cannot evaluate this constant expression with long long operand(s)';
          otherwise: Error(57);
          end; {case}
        writeln(msg^);