Rust-GCC
Rebinding match expressions on structs are unhandled
I tried this code:
struct Foo { a: i32 }
fn main() {
let a = Foo { a: 15 };
match a {
b => { }
}
}
this is very ugly Rust code, but it's used by rustc in a number of places for desugaring purposes, for example for loops - which get desugared as something of the form:
for <pat> in <head> <body>
becomes
{
let result = match <head>.into_iter() {
mut iter => loop { match iter.next() { ... } }
}
}
I expected to see this happen: no error: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=eedc6ff5cd556e9e703c52cf601d2f4c
The issue lies in here:
// rust-compile-expr.cc:952
if (scrutinee_kind == TyTy::TypeKind::ADT)
{
// this will need to change but for now the first pass implementation,
// lets assert this is the case
TyTy::ADTType *adt = static_cast<TyTy::ADTType *> (scrutinee_expr_tyty);
rust_assert (adt->is_enum ());
rust_assert (adt->number_of_variants () > 0);
}
we are asserting that the scrutinee we're matching on is an enum, which is not the case here
Instead, this happened: explanation
Meta
- What version of Rust GCC were you using, git sha if possible.
a very simple fix which is probably not correct is the following:
if (scrutinee_kind == TyTy::TypeKind::ADT)
{
// this will need to change but for now the first pass implementation,
// lets assert this is the case
TyTy::ADTType *adt = static_cast<TyTy::ADTType *> (scrutinee_expr_tyty);
if (adt->is_enum ())
rust_assert (adt->number_of_variants () > 0);
}
Hey, I wanted to work on this. Thinking trivially I would have thought of the same solution as the last reply but could you please explain why this might not be right? Testing locally the above solution does seem to remove the ICE.
@nobel-sh it removes the ICE, but I whipped it up in 5 minutes without really thinking or testing it out so that's why I'm saying it might not be correct :) should I assign you to the issue?