Type alias in struct copy causes compiler to crash #24581
Description
Describe the bug
Using a type alias as follows crashes the compiler
Reproduction Steps
module main
struct Cfg {
item string
}
type AliasCfg = Cfg
fn foo(cfg &AliasCfg) {
mut acfg := &AliasCfg{
...cfg
}
}
fn main() {
}v run .
Expected Behavior
Should not crash
Current Behavior
V panic: as cast: cannot cast `v.ast.Alias` to `v.ast.Struct`
v hash: 52c7130
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:19800: at _v_panic: Backtrace
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:20274: by __as_cast
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:70939: by v__checker__Checker_struct_init
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:54393: by v__checker__Checker_expr
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:48689: by v__checker__Checker_assign_stmt
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:52889: by v__checker__Checker_stmt
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:53507: by v__checker__Checker_stmts_ending_with_expression
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:53484: by v__checker__Checker_stmts
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:61304: by v__checker__Checker_fn_decl
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:52937: by v__checker__Checker_stmt
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:50826: by v__checker__Checker_check
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:50889: by v__checker__Checker_check_files
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:116133: by v__builder__Builder_middle_stages
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:116171: by v__builder__Builder_front_and_middle_stages
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:118771: by v__builder__cbuilder__gen_c
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:118743: by v__builder__cbuilder__build_c
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:118734: by v__builder__cbuilder__compile_c
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:118651: by v__builder__Builder_rebuild
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:117804: by v__builder__compile
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:119169: by main__rebuild
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:119085: by main__main
v2.01JW401TWHRN7D237PB6SD54CR.tmp.c:119946: by main
Possible Solution
None
Additional Information/Context
No response
V version
V 0.4.10 52c7130
Environment details (OS name and version, etc.)
| V full version | V 0.4.10 da3112e.52c7130 |
|---|---|
| OS | macos, macOS, 15.5, 24F74 |
| Processor | 8 cpus, 64bit, little endian, Apple M2 |
| Memory | 0.16GB/8GB |
| V executable | /Users/mike/Documents/github/v/v |
| V last modified time | 2025-05-25 15:12:48 |
| V home dir | OK, value: /Users/mike/Documents/github/v |
| VMODULES | OK, value: /Users/mike/.vmodules |
| VTMP | OK, value: /tmp/v_501 |
| Current working dir | OK, value: /Users/mike/Documents/github/bug |
| env VFLAGS | "-path /Users/mike/Documents/github |
| Git version | git version 2.49.0 |
| V git status | weekly.2025.17-161-g52c7130a |
| .git/config present | true |
| cc version | Apple clang version 17.0.0 (clang-1700.0.13.3) |
| gcc version | Apple clang version 17.0.0 (clang-1700.0.13.3) |
| clang version | Apple clang version 17.0.0 (clang-1700.0.13.3) |
| tcc version | tcc version 0.9.28rc 2024-02-05 HEAD@105d70f7 (AArch64 Darwin) |
| tcc git status | thirdparty-macos-arm64 c8df4e27 |
| emcc version | N/A |
| glibc version | N/A |
Note
You can use the 👍 reaction to increase the issue's priority for developers.
Please note that only the 👍 reaction to the issue itself counts as a vote.
Other reactions and those to comments will not be taken into account.