fmt: keep module alias in struct decl field types (#7305)

vlib/v/fmt/fmt.v

@@ -615,7 +615,10 @@ pub fn (mut f Fmt) struct_decl(node ast.StructDecl) {
 		if comments_len + field.name.len > max {
 			max = comments_len + field.name.len
 		}
-		ft := f.no_cur_mod(f.table.type_to_str(field.typ))
+		mut ft := f.no_cur_mod(f.table.type_to_str(field.typ))
+		if !ft.starts_with('C.') && !ft.starts_with('JS.') {
+			ft = f.short_module(ft)
+		}
 		field_types << ft
 		if ft.len > max_type {
 			max_type = ft.len
@@ -1290,13 +1293,13 @@ pub fn (mut f Fmt) short_module(name string) string {
 	if vals.len < 2 {
 		return name
 	}
-	mname := vals[vals.len - 2]
+	mname, tprefix := f.get_modname_prefix(vals[vals.len - 2])
 	symname := vals[vals.len - 1]
 	aname := f.mod2alias[mname]
 	if aname == '' {
 		return symname
 	}
-	return '${aname}.$symname'
+	return '$tprefix${aname}.$symname'
 }
 
 pub fn (mut f Fmt) lock_expr(lex ast.LockExpr) {
@@ -1987,3 +1990,14 @@ fn (mut f Fmt) is_external_name(name string) bool {
 	}
 	return false
 }
+
+fn (f Fmt) get_modname_prefix(mname string) (string, string) {
+	// ./tests/proto_module_importing_vproto_keep.vv to know, why here is checked for ']' and '&'
+	if !mname.contains(']') && !mname.contains('&') {
+		return mname, ''
+	}
+	after_rbc := mname.all_after_last(']')
+	after_ref := mname.all_after_last('&')
+	modname := if after_rbc.len < after_ref.len { after_rbc } else { after_ref }
+	return modname, mname.trim_suffix(modname)
+}

vlib/v/fmt/tests/import_with_alias_keep.vv

@@ -1,6 +1,15 @@
 import os
 import time as t
 
+struct Foo {
+	bar     t.Time
+	bars    []t.Time
+	barref  &t.Time
+	barrefs []&t.Time
+	c_type  C.some_struct
+	js_type JS.other_struct
+}
+
 fn main() {
 	println('start')
 	t.sleep_ms(500)