Add `-Z proc-macro-backtrace` to allow showing proc-macro panics
Fixes#75050
Previously, we would unconditionally suppress the panic hook during
proc-macro execution. This commit adds a new flag
`-Z proc-macro-backtrace`, which allows running the panic hook for
easier debugging.
Fixes#75050
Previously, we would unconditionally suppress the panic hook during
proc-macro execution. This commit adds a new flag
-Z proc-macro-backtrace, which allows running the panic hook for
easier debugging.
Previous implementation used the `Parser::parse_expr` function in order
to extract the format expression. If the first comma following the
format expression was mistakenly replaced with a dot, then the next
format expression was eaten by the function, because it looked as a
syntactically valid expression, which resulted in incorrectly spanned
error messages.
The way the format expression is exctracted is changed: we first look at
the first available token in the first argument supplied to the
`format!` macro call. If it is a string literal, then it is promoted as
a format expression immediatly, otherwise we fall back to the original
`parse_expr`-related method.
This allows us to ensure that the parser won't consume too much tokens
when a typo is made.
A test has been created so that it is ensured that the issue is properly
fixed.
I've tried a few ways of implementing this, but each fell short.
Adding an auxiliary `_Idx` associated type to `Analysis` that defaults
to `!` but is overridden in the blanket impl of `Analysis` for `A:
GenKillAnalysis` to `A::Idx` seems promising, but the trait solver is
unable to prove equivalence between `A::Idx` and `A::_Idx` within the
overridden version of `into_engine`. Without full-featured
specialization, removing `into_engine` or splitting it into a different
trait would have a significant ergonomic penalty.
Alternatively, we could erase the index type and store a
`GenKillSet<u32>` as well as a function pointer for transmuting between
`&mut A::Domain` and `&mut BitSet<u32>` in the hopes that LLVM can
devirtualize a simple function pointer better than the boxed closure.
However, this is brittle, requires `unsafe` code, and doesn't work for
index types that aren't the same size as a `u32` (e.g. `usize`) since
`GenKillSet` stores a `HybridBitSet`, which may be a `Vec<I>`. Perhaps
safe transmute could help here?
A few small cleanups to `BitSet` and friends:
- Overload `clone_from` for `BitSet`.
- Improve `Debug` represenation of `HybridBitSet`.
- Make `HybridBitSet::domain_size` public.
- Don't require `T: Idx` at the type level. The `Idx` bound is still on
most `BitSet` methods, but like `HashMap`, it doesn't need to be
satisfied for the type to exist.
This commit removes the obsolete printer and replaces all uses of it
with `FmtPrinter`. Of the replaced uses, all but one use was in `debug!`
logging, two cases were notable:
- `MonoItem::to_string` is used in `-Z print-mono-items` and therefore
affects the output of all codegen-units tests.
- `DefPathBasedNames` was used in `librustc_codegen_llvm/type_of.rs`
with `LLVMStructCreateNamed` and that'll now get different values, but
this should result in no functional change.
Signed-off-by: David Wood <david@davidtw.co>
This commit moves `transparent_newtype_field` and `is_zst` to
`LateContext` where they are used, rather than being on the `VariantDef`
and `TyS` types.
Signed-off-by: David Wood <david@davidtw.co>
StringReader is an intornal abstraction which at the moment changes a
lot, so these unit tests cause quite a bit of friction.
Moving them to rustc_lexer and more ingerated-testing style should
make them much less annoying, hopefully without decreasing their
usefulness much.
Note that coloncolon tests are removed (it's unclear what those are
testing).
\r\n tests are removed as well, as we normalize line endings even
before lexing.
Fixes#75930
This changes the tokens seen by a proc-macro. However, ising a `#[cfg]` attribute
on a generic paramter is unusual, and combining it with a proc-macro
derive is probably even more unusual. I don't expect this to cause any
breakage.
