transpile: Make cast from bool to pointer compile through size_t
#1134
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Similar to immunant#1030. Fixes immunant#1077.
kkysen
changed the title
bool to pointer compile through size_t
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LGTM. Same exact thing as #1030 except it's through size_t.
One thing that we should keep in mind is that #![feature(strict_provenance)] will probably be stabilized soon (rust-lang/rust#130350), and at that point, it'd probably be better to be more specific about this.
In #1077, @jorendorff said this was the reason why this is done:
(Why, you might ask, would anyone ever do this in real code. The answer is that C doesn't have generics, so projects will have, say, a single hash table type with
void *values, and store booleans in it by casting.)
This seems likely, as a provenance-preserving pointer cast through a bool does not make any sense, as false/0 is null and true/1 should almost always be an invalid address as well. Thus, we should be able to unconditionally use ptr::without_provenance for this cast once strict_provenance is stabilized.
| } else if target_ty_ctype.is_pointer() && source_ty_kind.is_bool() { | ||
| val.and_then(|x| { | ||
| Ok(WithStmts::new_val(mk().cast_expr( | ||
| mk().cast_expr(x, mk().path_ty(vec!["libc", "size_t"])), |
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We really should change these to core::ffi:: instead of libc:: at some point, but it's fine here; that's what we've done so far.
Similar to
c2rust transpile: When castingbools to floats, go through the integral typeu8#1030.Fixes Casting bool to pointer type results in invalid Rust #1077.