Put a constraint type on every ADT def, such that the ADT def is sized iff the constraint
type is, and use that in selection. This ignores types that are obviously sized.
This improves typeck performance by ~15%.
E0269: add suggestion to check for trailing semicolons
In situations where the value of the last expression must be inferred,
rustc will not emit the "you might need to remove the semicolon" warning,
so at least note this in the extended description.
Fixes: #30497
Overhaul borrowck error messages and compiler error formatting generally
This is a major overhaul of how the compiler reports errors. The primary goal is to be able to give many spans within the same overall context, such as this:
```
./borrow-errors.rs:73:17: 73:20: error: cannot borrow `*vec` as immutable because previous closure requires unique access [E0501]
70 let append = |e| {
~~~ closure construction occurs here
71 vec.push(e)
~~~ previous borrow occurs due to use of `vec` in closure
72 };
73 let data = &vec[3];
~~~ borrow occurs here
74 }
~ borrow from closure ends here
```
However, in the process we made a number of other changes:
- Removed the repetitive filenames from snippets and just give the line number.
- Color the line numbers blue so they "fade away"
- Remove the file name and line number from the error code suggestions since they don't seem to fit anymore. (This should probably happen in more places, like existing notes.)
- Newlines in between errors to help group them better.
This PR is not quite ready to land, but we thought it made sense to stop here and get some feedback from people at large. It'd be great if people can check out the branch and play with it. We'd be especially interested in hearing about cases that don't look good with the new formatting (I suspect they exist).
Here is a checklist of some pending work items for this PR. Some of them may be best left for follow-up PRs:
- [x] Accommodate multiple files in a `MultiSpan` (this should be easy)
- In this case, we want to print filenames though.
- [x] Remove duplicate E0500 code.
- [x] Make the header message bold, rather than current hack that makes all errors/warnings bold
- [x] Update warning text color (yellow is hard to read w/ a white background)
Moved numerous follow-ups to: https://github.com/rust-lang/rust/issues/33240
Joint work with @jonathandturner.
Fixes https://github.com/rust-lang/rust/issues/3533
Add CodeGen options to optimize for size.
Add CodeGen options to annotate functions with the attributes OptimizeSize and/or MinSize used by LLVM to reduce .text size.
Closes#32296
The extra filename and line was mainly there to keep the indentation
relative to the main snippet; now that this doesn't include
filename/line-number as a prefix, it is distracted.
This API pulls the "expected type foo, found type bar" out after the
main snippet. There are some other places where it makes sense, but this
is a start.
Major changes:
- Remove old snippet rendering code and use the new stuff.
- Introduce `span_label` method to add a label
- Remove EndSpan mode and replace with a fn to get the last
character of a span.
- Stop using `Option<MultiSpan>` and just use an empty `MultiSpan`
- and probably a bunch of other stuff :)
In situations where the value of the last expression must be inferred,
rustc will not emit the "you might need to remove the semicolon" warning,
so at least note this in the extended description.
Fixes: #30497
rustc_driver: Allow running the compiler with a FileLoader
cc @nrc. I chose to implement this in such a way that it doesn't break anything. Please let me know if you want me to change anything.
In fact, we make JSOn the default and add an option for save-analysis-csv for the legacy behaviour.
We also rename some bits and pieces `dxr` -> `save-analysis`
Suppress fallback and ambiguity errors
If the infcx has observed other errors, then suppress both default type
parameter fallback (which can be unreliable, as the full constraint set
is not available) and errors related to unresovled
variables (annoyingly, integer type variables cannot currently be
unified with error, so that has to be a separate mechanism). Also add a
flag to `infcx` to allow us to independently indicate when we have
observed an error and hence should trigger this suppression mode.
Fixes#31997
cc @alexcrichton
r? @arielb1
Paths are mostly parsed without taking whitespaces into account, e.g. `std :: vec :: Vec :: new ()` parses successfully, however, there are some special cases involving keywords `super`, `self` and `Self`. For example, `self::` is considered a path start only if there are no spaces between `self` and `::`. These restrictions probably made sense when `self` and friends weren't keywords, but now they are unnecessary.
The first two commits remove this special treatment of whitespaces by removing `token::IdentStyle` entirely and therefore fix https://github.com/rust-lang/rust/issues/14109.
This change also affects naked `self` and `super` (which are not tightly followed by `::`, obviously) they can now be parsed as paths, however they are still not resolved correctly in imports (cc @jseyfried, see `compile-fail/use-keyword.rs`), so https://github.com/rust-lang/rust/issues/29036 is not completely fixed.
The third commit also makes `super`, `self`, `Self` and `static` keywords nominally (before this they acted as keywords for all purposes) and removes most of remaining \"special idents\".
The last commit (before tests) contains some small improvements - some qualified paths with type parameters are parsed correctly, `parse_path` is not used for parsing single identifiers, imports are sanity checked for absence of type parameters - such type parameters can be generated by syntax extensions or by macros when https://github.com/rust-lang/rust/issues/10415 is fixed (~~soon!~~already!).
This patch changes some pretty basic things in `libsyntax`, like `token::Token` and the keyword list, so it's a plugin-[breaking-change].
r? @eddyb
MIR: Do not require END_BLOCK to always exist
Basically, all this does, is removing restriction for END_BLOCK to exist past the first invocation of RemoveDeadBlocks pass. This way for functions whose CFG does not reach the `END_BLOCK` end up not containing the block.
As far as the implementation goes, I’m not entirely satisfied with the `BasicBlock::end_block`. I had hoped to make `new` a `const fn` and then just have a `const END_BLOCK` private to mir::build, but it turns out that constant functions don’t yet support conditionals nor a way to assert.
Compute `target_feature` from LLVM
This is a work-in-progress fix for #31662.
The logic that computes the target features from the command line has been replaced with queries to the `TargetMachine`.
Compute LLVM-agnostic type layouts in rustc.
Layout for monomorphic types, and some polymorphic ones (e.g. `&T` where `T: Sized`),
can now be computed by rustc without involving LLVM in the actual process.
This gives rustc the ability to evaluate `size_of` or `align_of`, as well as obtain field offsets.
MIR-based CTFE will eventually make use of these layouts, as will MIR trans, shortly.
Layout computation also comes with a `[breaking-change]`, or two:
* `"data-layout"` is now mandatory in custom target specifications, reverting the decision from #27076.
This string is needed because it describes endianness, pointer size and alignments for various types.
We have the first two and we could allow tweaking alignments in target specifications.
Or we could also extract the data layout from LLVM and feed it back into rustc.
However, that can vary with the LLVM version, which is fragile and undermines stability.
For built-in targets, I've added a check that the hardcoded data-layout matches LLVM defaults.
* `transmute` calls are checked in a stricter fashion, which fixes#32377
To expand on `transmute`, there are only 2 allowed patterns: between types with statically known sizes and between pointers with the same potentially-unsized "tail" (which determines the type of unsized metadata they use, if any).
If you're affected, my suggestions are:
* try to use casts (and raw pointer deref) instead of transmutes
* *really* try to avoid `transmute` where possible
* if you have a structure, try working on individual fields and unpack/repack the structure instead of transmuting it whole, e.g. `transmute::<RefCell<Box<T>>, RefCell<*mut T>>(x)` doesn't work, but `RefCell::new(Box::into_raw(x.into_inner()))` does (and `Box::into_raw` is just a `transmute`)
