checker: add T.typ and T.unaliased_typ checking to $match (fix #25200) (#25202)

Author: felipensp

vlib/v/checker/match.v

@@ -104,6 +104,10 @@ fn (mut c Checker) match_expr(mut node ast.MatchExpr) ast.Type {
 						if c.comptime.inside_comptime_for && node.cond.field_name in ['name', 'typ'] {
 							// hack: `typ` is just for bypass the error test, because we don't know it is a type match or a value match righ now
 							comptime_match_cond_value = c.comptime.comptime_for_field_value.name
+						} else if mut node.cond.expr is ast.Ident
+							&& node.cond.gkind_field in [.typ, .unaliased_typ] {
+							left_type := c.get_expr_type(node.cond.expr)
+							comptime_match_cond_value = c.table.type_to_str(left_type)
 						} else {
 							c.error('`${node.cond}` is not `\$for` field.name.', node.cond.pos)
 							return ast.void_type

vlib/v/tests/comptime/comptime_match_unaliased_typ_test.v

@@ -0,0 +1,35 @@
+fn check_unaliased[T](t T) bool {
+	$match T.unaliased_typ {
+		int {
+			return true
+		}
+		$else {
+			return false
+		}
+	}
+}
+
+fn check_typ[T](t T) bool {
+	$match T.typ {
+		int {
+			return true
+		}
+		$else {
+			return false
+		}
+	}
+}
+
+type FooInt = int
+
+fn test_main() {
+	assert check_unaliased(1)
+	assert !check_unaliased('')
+	assert !check_unaliased(1.2)
+	assert check_unaliased(FooInt(0))
+
+	assert check_typ(1)
+	assert !check_typ('')
+	assert !check_typ(1.2)
+	assert !check_typ(FooInt(0))
+}