From 3ab660b4c67725135218c6cc25b1a9db21557d3b Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Sat, 3 May 2025 07:01:14 -0300
Subject: [PATCH] comptime: fix `$if var.return_type == 1 {` (fix #24391)
 (#24393)

---
 vlib/v/checker/if.v                             | 17 ++++++++++++-----
 vlib/v/gen/c/comptime.v                         | 15 +++++++++++++++
 vlib/v/tests/comptime/comptime_call_void_test.v | 15 +++++++++++++++
 3 files changed, 42 insertions(+), 5 deletions(-)
 create mode 100644 vlib/v/tests/comptime/comptime_call_void_test.v

diff --git a/vlib/v/checker/if.v b/vlib/v/checker/if.v
index e33801af5..faf305c6f 100644
--- a/vlib/v/checker/if.v
+++ b/vlib/v/checker/if.v
@@ -182,11 +182,10 @@ fn (mut c Checker) if_expr(mut node ast.IfExpr) ast.Type {
 								} else {
 									.skip
 								}
-							} else if comptime_field_name == c.comptime.comptime_for_method_var {
-								if left.field_name == 'return_type' {
-									skip_state = c.check_compatible_types(c.unwrap_generic(c.comptime.comptime_for_method_ret_type),
-										right as ast.TypeNode)
-								}
+							} else if comptime_field_name == c.comptime.comptime_for_method_var
+								&& left.field_name == 'return_type' {
+								skip_state = c.check_compatible_types(c.unwrap_generic(c.comptime.comptime_for_method_ret_type),
+									right as ast.TypeNode)
 							} else if comptime_field_name in [
 								c.comptime.comptime_for_variant_var,
 								c.comptime.comptime_for_enum_var,
@@ -286,6 +285,14 @@ fn (mut c Checker) if_expr(mut node ast.IfExpr) ast.Type {
 									}
 								}
 							}
+						} else if comptime_field_name == c.comptime.comptime_for_method_var {
+							if left.field_name == 'return_type' {
+								skip_state = if c.unwrap_generic(c.comptime.comptime_for_method_ret_type).idx() == right.val.i64() {
+									ComptimeBranchSkipState.eval
+								} else {
+									ComptimeBranchSkipState.skip
+								}
+							}
 						} else if left.expr is ast.TypeOf {
 							skip_state = if left.expr.typ.nr_muls() == right.val.i64() {
 								ComptimeBranchSkipState.eval
diff --git a/vlib/v/gen/c/comptime.v b/vlib/v/gen/c/comptime.v
index bd0acf3d0..cdee0a155 100644
--- a/vlib/v/gen/c/comptime.v
+++ b/vlib/v/gen/c/comptime.v
@@ -655,6 +655,21 @@ fn (mut g Gen) comptime_if_cond(cond ast.Expr, pkg_exist bool) (bool, bool) {
 									g.write('0')
 								}
 								return is_true, true
+							} else if g.comptime.comptime_for_method_var != ''
+								&& cond.left.expr is ast.Ident
+								&& cond.left.expr.name == g.comptime.comptime_for_method_var
+								&& cond.left.field_name == 'return_type' {
+								is_true := match cond.op {
+									.eq { g.comptime.comptime_for_method_ret_type.idx() == cond.right.val.i64() }
+									.ne { g.comptime.comptime_for_method_ret_type.idx() != cond.right.val.i64() }
+									else { false }
+								}
+								if is_true {
+									g.write('1')
+								} else {
+									g.write('0')
+								}
+								return is_true, true
 							}
 						}
 					}
diff --git a/vlib/v/tests/comptime/comptime_call_void_test.v b/vlib/v/tests/comptime/comptime_call_void_test.v
new file mode 100644
index 000000000..8ef58869b
--- /dev/null
+++ b/vlib/v/tests/comptime/comptime_call_void_test.v
@@ -0,0 +1,15 @@
+struct Struct {}
+
+fn (s Struct) func() {}
+
+fn test_main() {
+	$for method in Struct.methods {
+		println('${method.name}: ${method.return_type}')
+		$if method.return_type == 1 {
+			assert true
+		}
+		$if method.return_type == 11 {
+			assert false
+		}
+	}
+}
-- 
2.39.5