- Compiler crash using ?? with a void? macro #2973

releasenotes.md

@@ -58,6 +58,7 @@
 - Member access on a struct returned by the assignment expression, cause crash #2947
 - Trying to slice an indexable type leads to misleading error message #2958
 - Warn on use of visibility modifiers on methods. #2962
+- Compiler crash using `??` with a `void?` macro #2973
 
 ## 0.7.9 Change list
 

src/compiler/llvm_codegen_expr.c

@@ -3921,7 +3921,7 @@ static void llvm_emit_else(GenContext *c, BEValue *be_value, Expr *expr)
 	assert(success_end_block && else_block_exit);
 
 	// We might have a void here
-	if (!real_value.value)
+	if (!real_value.value || LLVMIsUndef(real_value.value))
 	{
 		assert(type_flatten(expr->type) == type_void);
 		assert(!else_value.value);

test/test_suite/errors/else_check_void.c3t

@@ -0,0 +1,17 @@
+module test;
+
+faultdef MALFORMED_RESPONSE;
+macro void? set_field(String[] tokens)
+{
+	if (tokens.len < 2) return MALFORMED_RESPONSE~;
+}
+
+fn void main()
+{
+	String[] tokens = { "a", "b" };
+	set_field(tokens) ?? (void)1;
+}
+
+/* #expect: test.ll
+
+fefe