parser: fix vls mode strut mut keyword (fix #25548) (#25551)

Author: kbkpbot

vlib/v/parser/struct.v

@@ -132,7 +132,7 @@ fn (mut p Parser) struct_decl(is_anon bool) ast.StructDecl {
 		}
 		p.check(.lcbr)
 		// if p.is_vls && p.tok.kind == .key_struct { // p.tok.is_key() {
-		if p.is_vls && p.tok.is_key() {
+		if p.is_vls && p.tok.is_key() && p.tok.kind != .key_mut {
 			// End parsing after `struct Foo {` in vls mode to avoid lots of junk errors
 			// If next token after { is a key, the struct wasn't finished
 			p.error('expected `}` to finish a struct definition')

vlib/v/tests/vls/struct_check_test.v

@@ -0,0 +1,61 @@
+import os
+import term
+import v.util.diff
+
+const vroot = os.real_path(@VMODROOT)
+const tmp_dir = os.real_path(os.temp_dir())
+
+const text_file = os.join_path(vroot, 'vlib', 'v', 'tests', 'vls', 'struct_text.vv')
+
+fn testsuite_begin() {
+	eprintln('testsuite_begin, text_file = ${text_file}')
+}
+
+fn testsuite_end() {
+}
+
+struct TestData {
+	cmd    string
+	output string
+}
+
+const test_data = [
+	TestData{
+		cmd:    'v -check -vls-mode ${os.quoted_path(text_file)}'
+		output: '' // for a struct with `mut:` in it, should report no error
+	},
+]
+
+fn test_main() {
+	mut total_errors := 0
+
+	for t in test_data {
+		res := os.execute(t.cmd)
+		if res.exit_code < 0 {
+			println('fail execute ${t.cmd}')
+			panic(res.output)
+		}
+		res_output := $if windows {
+			res.output.replace('\r\n', '\n')
+		} $else {
+			res.output
+		}
+		if t.output != res_output {
+			println('${term.red('FAIL')} ${t.cmd}')
+			if diff_ := diff.compare_text(t.output, res_output) {
+				println(term.header('difference:', '-'))
+				println(diff_)
+			} else {
+				println(term.header('expected:', '-'))
+				println(t.output)
+				println(term.header('found:', '-'))
+				println(res_output)
+			}
+			println(term.h_divider('-'))
+			total_errors++
+		} else {
+			println('${term.green('OK  ')} ${t.cmd}')
+		}
+	}
+	assert total_errors == 0
+}

vlib/v/tests/vls/struct_text.vv

@@ -0,0 +1,7 @@
+module main
+
+struct MyS {
+mut:
+	a int
+	b string
+}