ir_constant_expression: Assert that both operands share a base type.
diff --git a/src/glsl/ir_constant_expression.cpp b/src/glsl/ir_constant_expression.cpp
index 6d6ee09..610d947 100644
--- a/src/glsl/ir_constant_expression.cpp
+++ b/src/glsl/ir_constant_expression.cpp
@@ -141,6 +141,9 @@
 	 return;
    }
 
+   if (op[1] != NULL)
+      assert(op[0]->type->base_type == op[1]->type->base_type);
+
    switch (ir->operation) {
    case ir_unop_logic_not:
       assert(op[0]->type->base_type == GLSL_TYPE_BOOL);