parser, checker: check undefined ident in if expr using generic type name (#14734)

vlib/v/checker/tests/generic_type_name_in_non_generic_function.out

@@ -1,4 +1,4 @@
-vlib/v/checker/tests/generic_type_name_in_non_generic_function.vv:3:10: error: unexpected generic variable in non-generic function `main`
+vlib/v/checker/tests/generic_type_name_in_non_generic_function.vv:3:10: error: undefined ident: `A`
     1 | fn main() {
     2 |     c := u8(`D`)
     3 |     if c >= A && c <= Z {

vlib/v/parser/expr.v

@@ -55,7 +55,7 @@ pub fn (mut p Parser) check_expr(precedence int) ?ast.Expr {
 				p.error_with_pos("deprecated map syntax, use syntax like `{'age': 20}`",
 					p.tok.pos())
 			} else {
-				if p.inside_if && p.is_generic_name() && p.peek_tok.kind != .dot {
+				if p.inside_comptime_if && p.is_generic_name() && p.peek_tok.kind != .dot {
 					// $if T is string {}
 					p.expecting_type = true
 				}

vlib/v/parser/if_match.v

@@ -27,6 +27,9 @@ fn (mut p Parser) if_expr(is_comptime bool) ast.IfExpr {
 	mut prev_guard := false
 	for p.tok.kind in [.key_if, .key_else] {
 		p.inside_if = true
+		if is_comptime {
+			p.inside_comptime_if = true
+		}
 		start_pos := if is_comptime { p.prev_tok.pos().extend(p.tok.pos()) } else { p.tok.pos() }
 		if p.tok.kind == .key_else {
 			comments << p.eat_comments()
@@ -40,6 +43,7 @@ fn (mut p Parser) if_expr(is_comptime bool) ast.IfExpr {
 				// else {
 				has_else = true
 				p.inside_if = false
+				p.inside_comptime_if = false
 				end_pos := p.prev_tok.pos()
 				body_pos := p.tok.pos()
 				p.open_scope()
@@ -141,6 +145,7 @@ fn (mut p Parser) if_expr(is_comptime bool) ast.IfExpr {
 		end_pos := p.prev_tok.pos()
 		body_pos := p.tok.pos()
 		p.inside_if = false
+		p.inside_comptime_if = false
 		p.open_scope()
 		stmts := p.parse_block_no_scope(false)
 		branches << ast.IfBranch{

vlib/v/parser/parser.v

@@ -35,6 +35,7 @@ mut:
 	inside_vlib_file          bool // true for all vlib/ files
 	inside_test_file          bool // when inside _test.v or _test.vv file
 	inside_if                 bool
+	inside_comptime_if        bool
 	inside_if_expr            bool
 	inside_if_cond            bool
 	inside_ct_if_expr         bool
@@ -2419,7 +2420,7 @@ pub fn (mut p Parser) name_expr() ast.Expr {
 		&& (!p.inside_for || p.inside_select) && !known_var {
 		return p.struct_init(p.mod + '.' + p.tok.lit, false) // short_syntax: false
 	} else if p.peek_tok.kind == .lcbr
-		&& ((p.inside_if && lit0_is_capital && !known_var && language == .v)
+		&& ((p.inside_if && lit0_is_capital && p.tok.lit.len > 1 && !known_var && language == .v)
 		|| (p.inside_match_case && p.tok.kind == .name && p.peek_tok.pos - p.tok.pos == p.tok.len)) {
 		// `if a == Foo{} {...}` or `match foo { Foo{} {...} }`
 		return p.struct_init(p.mod + '.' + p.tok.lit, false)