all: s.contains(s2) instead of `in`

vlib/builtin/string.v

@@ -882,7 +882,7 @@ pub fn (s string) contains(substr string) bool {
 // contains_any returns `true` if the string contains any chars in `chars`.
 pub fn (s string) contains_any(chars string) bool {
 	for c in chars {
-		if c.ascii_str() in s {
+		if s.contains(c.ascii_str()) {
 			return true
 		}
 	}

vlib/v/checker/checker.v

@@ -780,6 +780,7 @@ pub fn (mut c Checker) infix_expr(mut infix_expr ast.InfixExpr) table.Type {
 					infix_expr.left_type = map_info.key_type
 				}
 				.string {
+					c.warn('use `str.contains(substr)` instead of `substr in str`', left_right_pos)
 					c.check_expected(left_type, right_type) or {
 						c.error('left operand to `$infix_expr.op` does not match: $err.msg',
 							left_right_pos)
@@ -4509,7 +4510,8 @@ pub fn (mut c Checker) ident(mut ident ast.Ident) table.Type {
 					}
 					if typ == table.error_type && c.expected_type == table.string_type
 						&& !c.using_new_err_struct && !c.inside_selector_expr
-						&& !c.inside_println_arg && 'v.' !in c.file.mod.name && !c.is_builtin_mod {
+						&& !c.inside_println_arg && !c.file.mod.name.contains('v.')
+						&& !c.is_builtin_mod {
 						//                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ <- TODO: remove; this prevents a failure in the `performance-regressions` CI job
 						c.warn('string errors are deprecated; use `err.msg` instead',
 							ident.pos)

vlib/v/gen/c/cgen.v

@@ -162,7 +162,7 @@ pub fn gen(files []ast.File, table &table.Table, pref &pref.Preferences) string
 	mut module_built := ''
 	if pref.build_mode == .build_module {
 		for file in files {
-			if pref.path in file.path
+			if file.path.contains(pref.path)
 				&& file.mod.short_name == pref.path.all_after_last(os.path_separator).trim_right(os.path_separator) {
 				module_built = file.mod.name
 				break

vlib/v/pref/pref.v

@@ -634,22 +634,19 @@ pub fn cc_from_string(cc_str string) CompilerType {
 	normalized_cc_array := normalized_cc.split('/')
 	last_elem := normalized_cc_array.last()
 	cc := last_elem.all_before('.')
-	if '++' in cc {
+	if cc.contains('++') {
 		return .cplusplus
 	}
-	if 'tcc' in cc {
+	if cc.contains('tcc') || cc.contains('tinyc') {
 		return .tinyc
 	}
-	if 'tinyc' in cc {
-		return .tinyc
-	}
-	if 'clang' in cc {
+	if cc.contains('clang') {
 		return .clang
 	}
-	if 'mingw' in cc {
+	if cc.contains('mingw') {
 		return .mingw
 	}
-	if 'msvc' in cc {
+	if cc.contains('msvc') {
 		return .msvc
 	}
 	return .gcc

vlib/v/table/types.v

@@ -972,7 +972,7 @@ pub fn (t &TypeSymbol) embed_name() string {
 	mut embed_name := t.name.split('.').last()
 	// remove generic part from name
 	// Abc<int> => Abc
-	if '<' in embed_name {
+	if embed_name.contains('<') {
 		embed_name = embed_name.split('<')[0]
 	}
 	return embed_name

vlib/v/util/module.v

@@ -61,7 +61,7 @@ pub fn mod_path_to_full_name(mod string, path string) ?string {
 	vmod_folders := ['vlib', '.vmodules', 'modules']
 	mut in_vmod_path := false
 	for vmod_folder in vmod_folders {
-		if vmod_folder + os.path_separator in path {
+		if path.contains(vmod_folder + os.path_separator) {
 			in_vmod_path = true
 			break
 		}

vlib/vweb/request.v

@@ -66,7 +66,7 @@ fn parse_request_line(s string) ?(http.Method, urllib.URL, http.Version) {
 }
 
 fn parse_header(s string) ?(string, string) {
-	if ':' !in s {
+	if !s.contains(':') {
 		return error('missing colon in header')
 	}
 	words := s.split_nth(':', 2)