autofree: fix codegen for comptime selector usage (fix #24655) (#24697)

vlib/v/checker/fn.v

@@ -731,7 +731,7 @@ fn (mut c Checker) call_expr(mut node ast.CallExpr) ast.Type {
 			if arg.typ != ast.string_type {
 				continue
 			}
-			if arg.expr in [ast.Ident, ast.StringLiteral, ast.SelectorExpr]
+			if arg.expr in [ast.Ident, ast.StringLiteral, ast.SelectorExpr, ast.ComptimeSelector]
 				|| (arg.expr is ast.CallExpr && arg.expr.or_block.kind != .absent) {
 				// Simple expressions like variables, string literals, selector expressions
 				// (`x.field`) can't result in allocations and don't need to be assigned to

vlib/v/slow_tests/valgrind/comptime_selector.v

@@ -0,0 +1,52 @@
+module main
+
+import encoding.binary
+import math
+
+fn main() {
+	value := Vector3D{
+		x: 1.0
+		y: 2.0
+		z: 3.0
+		v: 'bob'
+	}
+	mut buf := []u8{len: 0, cap: 12}
+	serialize_to(value, mut buf)!
+	println(buf)
+}
+
+type Primitive = f64 | f32 | rune | i32 | u32 | i16 | u16 | i8 | u8 | bool
+
+struct Vector3D {
+	x f32
+	y f32
+	z f32
+	v string
+}
+
+fn serialize_to[T](val T, mut output []u8) ! {
+	$for v in Primitive.variants {
+		$if v.typ is T {
+			output << binary.encode_binary(val, binary.EncodeConfig{
+				buffer_len: int(sizeof[T]())
+				big_endian: false
+			})!
+			return
+		}
+	}
+	$if T is string {
+		if val.len > math.maxof[u16]() {
+			return error('String too long to serialize')
+		}
+		bytes := val.bytes()
+		output << binary.encode_binary(u16(bytes.len), binary.EncodeConfig{
+			buffer_len: int(sizeof[u16]())
+			big_endian: false
+		})!
+		output << bytes
+		return
+	}
+	$for field in T.fields {
+		serialize_to(val.$(field.name), mut output)!
+	}
+}

vlib/v/slow_tests/valgrind/valgrind_test.v

@@ -32,6 +32,7 @@ const skip_valgrind_files = [
 	'vlib/v/slow_tests/valgrind/option_simple.v',
 	'vlib/v/slow_tests/valgrind/string_plus_string_plus.v',
 	'vlib/v/slow_tests/valgrind/import_x_json2.v',
+	'vlib/v/slow_tests/valgrind/comptime_selector.v',
 ]
 
 fn vprintln(s string) {