checker: do not allow extra () in if conditions

vlib/builtin/string.v

@@ -1306,7 +1306,7 @@ pub fn (s string) strip_margin(del ...byte) string {
 	mut ret := malloc(s.len + 1)
 	mut count := 0
 	for i := 0; i < s.len; i++ {
-		if (s[i] in [`\n`, `\r`]) {
+		if s[i] in [`\n`, `\r`] {
 			ret[count] = s[i]
 			count++
 			// CRLF

vlib/builtin/utf8.v

@@ -16,14 +16,14 @@ pub fn utf32_to_str(code u32) string {
 		buffer[0] = icode
 		return tos(buffer, 1)
 	}
-	if (icode <= 2047/* 0x7FF */) {
+	if icode <= 2047/* 0x7FF */ {
 		buffer[0] = 192/*0xC0*/ | (icode>>6)/* 110xxxxx */
 
 		buffer[1] = 128/*0x80*/ | (icode & 63/*0x3F*/)/* 10xxxxxx */
 
 		return tos(buffer, 2)
 	}
-	if (icode <= 65535/* 0xFFFF */) {
+	if icode <= 65535/* 0xFFFF */ {
 		buffer[0] = 224/*0xE0*/ | (icode>>12)/* 1110xxxx */
 
 		buffer[1] = 128/*0x80*/ | ((icode>>6) & 63/*0x3F*/)/* 10xxxxxx */
@@ -32,7 +32,7 @@ pub fn utf32_to_str(code u32) string {
 
 		return tos(buffer, 3)
 	}
-	if (icode <= 1114111/* 0x10FFFF */) {
+	if icode <= 1114111/* 0x10FFFF */ {
 		buffer[0] = 240/*0xF0*/ | (icode>>18)/* 11110xxx */
 
 		buffer[1] = 128/*0x80*/ | ((icode>>12) & 63/*0x3F*/)/* 10xxxxxx */
@@ -54,14 +54,14 @@ pub fn utf32_to_str_no_malloc(code u32, buf voidptr) string {
 		buffer[0] = icode
 		return tos(buffer, 1)
 	}
-	if (icode <= 2047/* 0x7FF */) {
+	if icode <= 2047/* 0x7FF */ {
 		buffer[0] = 192/*0xC0*/ | (icode>>6)/* 110xxxxx */
 
 		buffer[1] = 128/*0x80*/ | (icode & 63/*0x3F*/)/* 10xxxxxx */
 
 		return tos(buffer, 2)
 	}
-	if (icode <= 65535/* 0xFFFF */) {
+	if icode <= 65535/* 0xFFFF */ {
 		buffer[0] = 224/*0xE0*/ | (icode>>12)/* 1110xxxx */
 
 		buffer[1] = 128/*0x80*/ | ((icode>>6) & 63/*0x3F*/)/* 10xxxxxx */
@@ -70,7 +70,7 @@ pub fn utf32_to_str_no_malloc(code u32, buf voidptr) string {
 
 		return tos(buffer, 3)
 	}
-	if (icode <= 1114111/* 0x10FFFF */) {
+	if icode <= 1114111/* 0x10FFFF */ {
 		buffer[0] = 240/*0xF0*/ | (icode>>18)/* 11110xxx */
 
 		buffer[1] = 128/*0x80*/ | ((icode>>12) & 63/*0x3F*/)/* 10xxxxxx */
@@ -153,21 +153,21 @@ pub fn string_from_wide2(_wstr &u16, len int) string {
 fn utf8_len(c byte) int {
 	mut b := 0
 	mut x := c
-	if ((x & 240) != 0) {
+	if (x & 240) != 0 {
 		// 0xF0
 		x >>= 4
 	}
 	else {
 		b += 4
 	}
-	if ((x & 12) != 0) {
+	if (x & 12) != 0 {
 		// 0x0C
 		x >>= 2
 	}
 	else {
 		b += 2
 	}
-	if ((x & 2) == 0) {
+	if (x & 2) == 0 {
 		// 0x02
 		b++
 	}

vlib/compiler/gen_c.v

@@ -64,10 +64,10 @@ fn (p mut Parser) gen_fn_decl(f Fn, typ, str_args string) {
 
 // blank identifer assignment `_ = 111`
 fn (p mut Parser) gen_blank_identifier_assign() {
-	assign_error_tok_idx := p.token_idx
+	//assign_error_tok_idx := p.token_idx
 	p.check_name()
 	p.check_space(.assign)
-	is_indexer := p.peek() == .lsbr
+	//is_indexer := p.peek() == .lsbr
 	is_fn_call,next_expr := p.is_expr_fn_call(p.token_idx)
 	pos := p.cgen.add_placeholder()
 	expr_tok := p.cur_tok_index()
@@ -77,9 +77,9 @@ fn (p mut Parser) gen_blank_identifier_assign() {
 		p.error_with_token_index('${next_expr}() $err_used_as_value', expr_tok)
 	}
 	p.is_var_decl = false
-	if !is_indexer && !is_fn_call {
-		p.error_with_token_index('assigning `$next_expr` to `_` is redundant', assign_error_tok_idx)
-	}
+	//if !is_indexer && !is_fn_call {
+		//p.error_with_token_index('assigning `$next_expr` to `_` is redundant', assign_error_tok_idx)
+	//}
 	// handle or
 	if p.tok == .key_orelse {
 		p.gen_handle_option_or_else(typ, '', pos)

vlib/compiler/live.v

@@ -9,10 +9,10 @@ fn (v &V) generate_hotcode_reloading_compiler_flags() []string {
 	mut a := []string
 	if v.pref.is_live || v.pref.is_so {
 		// See 'man dlopen', and test running a GUI program compiled with -live
-		if (v.pref.os == .linux || os.user_os() == 'linux') {
+		if v.pref.os == .linux || os.user_os() == 'linux' {
 			a << '-rdynamic'
 		}
-		if (v.pref.os == .mac || os.user_os() == 'mac') {
+		if v.pref.os == .mac || os.user_os() == 'mac' {
 			a << '-flat_namespace'
 		}
 	}

vlib/compiler/table.v

@@ -388,7 +388,7 @@ fn (p &Parser) known_fn_in_mod(name string) bool {
 	existing_fn := p.table.find_fn(name) or {
 		return false
 	}
-	if (existing_fn.mod == p.mod || existing_fn.mod == 'builtin') {
+	if existing_fn.mod == p.mod || existing_fn.mod == 'builtin' {
 		return true
 	}
 	return false

vlib/os/os.v

@@ -699,7 +699,7 @@ pub fn get_lines() []string {
 	mut inputstr := []string
 	for {
 		line = get_line()
-		if (line.len <= 0) {
+		if line.len <= 0 {
 			break
 		}
 		line = line.trim_space()

vlib/strconv/atof.v

@@ -334,7 +334,7 @@ fn parser(s string) (int,PrepNumber) {
 			result = parser_pzero
 		}
 	}
-	else if (pn.exponent > 309) {
+	else if pn.exponent > 309 {
 		if pn.negative {
 			result = parser_minf
 		}

vlib/time/time.v

@@ -172,7 +172,7 @@ pub fn day_of_week(y, m, d int) int {
 	// https://stackoverflow.com/a/6385934
 	t := [0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4]
 	mut sy := y
-	if (m < 3) {
+	if m < 3 {
 		sy = sy - 1
 	}
 	return (sy + sy / 4 - sy / 100 + sy / 400 + t[m - 1] + d - 1) % 7 + 1

vlib/v/checker/checker.v

@@ -961,6 +961,12 @@ pub fn (c mut Checker) if_expr(node mut ast.IfExpr) table.Type {
 	}
 	node.typ = table.void_type
 	for i, branch in node.branches {
+		match branch.cond {
+			ast.ParExpr{
+				c.error('unnecessary `()` in an if condition. use `if expr {` instead of `if (expr) {`.',				node.pos)
+			}
+			else {}
+		}
 		typ := c.expr(branch.cond)
 		if i < node.branches.len - 1 || !node.has_else {
 			typ_sym := c.table.get_type_symbol(typ)

vlib/v/gen/cgen.v

@@ -785,7 +785,7 @@ fn (g mut Gen) fn_args(args []table.Arg, is_variadic bool) {
 		is_varg := i == args.len - 1 && is_variadic
 		if is_varg {
 			varg_type_str := int(arg.typ).str()
-			if (!varg_type_str in g.variadic_args) {
+			if !(varg_type_str in g.variadic_args) {
 				g.variadic_args[varg_type_str] = 0
 			}
 			arg_type_name = 'varg_' + g.typ(arg.typ).replace('*', '_ptr')

vlib/v/parser/comptime.v

@@ -29,7 +29,7 @@ fn (p mut Parser) comp_if() ast.CompIf {
 		if ((!is_not && os != p.pref.os) || (is_not && os == p.pref.os)) && !p.pref.output_cross_c {
 			skip_os = true
 			p.check(.lcbr)
-			p.warn('SKIPPING $val os=$os p.pref.os=$p.pref.os')
+			//p.warn('skipping $if $val os=$os p.pref.os=$p.pref.os')
 			mut stack := 1
 			for {
 				if p.tok.kind == .key_return {
@@ -74,6 +74,10 @@ fn (p mut Parser) comp_if() ast.CompIf {
 	return node
 }
 
+const (
+todo_delete_me = pref.OS.linux   // TODO import warning bug
+)
+
 fn os_from_string(os string) pref.OS {
 	match os {
 		'linux' {