add compile error for shifting by negative comptime integer

closes #698

1 files changed, 7 insertions, 0 deletions

diff --git a/src/ir.cpp b/src/ir.cpp
index 4c107ce767..fae3b82481 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -8816,6 +8816,13 @@ static TypeTableEntry *ir_analyze_bit_shift(IrAnalyze *ira, IrInstructionBinOp *
         if (op_id == IrBinOpBitShiftLeftLossy) {
             op_id = IrBinOpBitShiftLeftExact;
         }
+
+        if (casted_op2->value.data.x_bigint.is_negative) {
+            Buf *val_buf = buf_alloc();
+            bigint_append_buf(val_buf, &casted_op2->value.data.x_bigint, 10);
+            ir_add_error(ira, casted_op2, buf_sprintf("shift by negative value %s", buf_ptr(val_buf)));
+            return ira->codegen->builtin_types.entry_invalid;
+        }
     } else {
         TypeTableEntry *shift_amt_type = get_smallest_unsigned_int_type(ira->codegen,
                 op1->value.type->data.integral.bit_count - 1);