fmt: fix import with symbols (fix #12065) (#12069)

cmd/tools/vtest-cleancode.v

@@ -42,7 +42,6 @@ const (
 	]
 	vfmt_known_failing_exceptions   = arrays.merge(verify_known_failing_exceptions, [
 		'vlib/regex/regex_test.v' /* contains meaningfull formatting of the test case data */,
-		'vlib/readline/readline_test.v' /* vfmt eats `{ Readline }` from `import readline { Readline }` */,
 		'vlib/glm/glm.v' /* `mut res &f32` => `mut res f32`, which then fails to compile */,
 		'vlib/crypto/sha512/sha512block_generic.v' /* formatting of large constant arrays wraps to too many lines */,
 		'vlib/crypto/aes/const.v' /* formatting of large constant arrays wraps to too many lines */,

vlib/readline/readline_test.v

@@ -17,4 +17,4 @@ fn test_struct_readline() {
 	// eprintln('methods: $methods')
 	assert 'read_line_utf8' in methods
 	assert 'read_line' in methods
-}
+}

vlib/v/fmt/fmt.v

@@ -760,6 +760,7 @@ pub fn (mut f Fmt) branch_stmt(node ast.BranchStmt) {
 pub fn (mut f Fmt) comp_for(node ast.CompFor) {
 	typ := f.no_cur_mod(f.table.type_to_str_using_aliases(node.typ, f.mod2alias))
 	f.write('\$for $node.val_var in ${typ}.$node.kind.str() {')
+	f.mark_types_import_as_used(node.typ)
 	if node.stmts.len > 0 || node.pos.line_nr < node.pos.last_line {
 		f.writeln('')
 		f.stmts(node.stmts)

vlib/v/fmt/tests/import_with_symbols_keep.vv

@@ -0,0 +1,14 @@
+import readline { Readline }
+
+fn no_lines(s string) string {
+	return s.replace('\n', ' ')
+}
+
+fn main() {
+	mut methods := []string{}
+	$for method in Readline.methods {
+		methods << method.name
+	}
+	assert 'read_line_utf8' in methods
+	assert 'read_line' in methods
+}