checker: add support for static methods in @FN and @METHOD (#21990)

Author: Delta456

vlib/v/checker/checker.v

@@ -3546,7 +3546,11 @@ fn (mut c Checker) at_expr(mut node ast.AtExpr) ast.Type {
 			if c.table.cur_fn == unsafe { nil } {
 				return ast.void_type
 			}
-			node.val = c.table.cur_fn.name.all_after_last('.')
+			if _ := c.table.cur_fn.name.index('__static__') {
+				node.val = c.table.cur_fn.name.all_after_last('__static__')
+			} else {
+				node.val = c.table.cur_fn.name.all_after_last('.')
+			}
 		}
 		.method_name {
 			if c.table.cur_fn == unsafe { nil } {
@@ -3556,6 +3560,8 @@ fn (mut c Checker) at_expr(mut node ast.AtExpr) ast.Type {
 			if c.table.cur_fn.is_method {
 				node.val = c.table.type_to_str(c.table.cur_fn.receiver.typ).all_after_last('.') +
 					'.' + fname
+			} else if _ := fname.index('__static__') {
+				node.val = fname.all_before('__static__') + '.' + fname.all_after('__static__')
 			} else {
 				node.val = fname
 			}

vlib/v/tests/comptime_at_test.v

@@ -60,6 +60,12 @@ fn (mut t TestFn) tst_2(cb fn (int)) {
 	cb(1)
 }
 
+fn TestFn.static_fn() {
+	assert @FN == 'static_fn'
+	assert @METHOD == 'TestFn.static_fn'
+	assert @STRUCT == 'TestFn'
+}
+
 fn fn_name_mod_level() {
 	assert @FN == 'fn_name_mod_level'
 	assert @METHOD == 'fn_name_mod_level'
@@ -96,6 +102,7 @@ fn test_at_fn() {
 		t := i + 1
 		assert t == 2
 	})
+	TestFn.static_fn()
 }
 
 fn test_at_mod() {