- generate error instead of warning
- remove `RewindPoint` and just keep a copy of `Parser` to rewind state.
- `dont_parse_generics: bool` -> `parse_generics: bool`
- remove `eat_lt`
- move error handling code to separate method
```
warning: `<` is interpreted as a start of generic arguments for `usize`, not a comparison
--> $DIR/issue-22644.rs:16:33
|
16 | println!("{}", a as usize < b);
| - ^ interpreted as generic argument
| |
| not interpreted as comparison
|
help: if you want to compare the casted value then write:
| println!("{}", (a as usize) < b);
```
```
warning: `<` is interpreted as a start of generic arguments for `usize`, not comparison
--> $DIR/issue-22644.rs:16:33
|
16 | println!("{}", a as usize < b);
| ^ expected one of `!`, `(`, `+`, `,`, `::`, or `>` here
|
help: if you want to compare the casted value then write
| println!("{}", (a as usize) < b);
```
Parsing `a as usize > b` always works, but `a as usize < b` was a
parsing error because the parser would think the `<` started a generic
type argument for `usize`. The parser now attempts to parse as before,
and if a DiagnosticError is returned, try to parse again as a type with
no generic arguments. If this fails, return the original
`DiagnosticError`.
This is useful if parsing from stdin or a String and don't want to try and read in a module from another file. Instead we just leave a stub in the AST.
Minimize single span suggestions into a label
changes
```
14 | println!("☃{}", tup[0]);
| ^^^^^^
|
help: to access tuple elements, use tuple indexing syntax as shown
| println!("☃{}", tup.0);
```
into
```
14 | println!("☃{}", tup[0]);
| ^^^^^^ to access tuple elements, use `tup.0`
```
Also makes suggestions explicit in the backend in preparation of adding multiple suggestions to a single diagnostic. Currently that's already possible, but results in a full help message + modified code snippet per suggestion, and has no rate limit (might show 100+ suggestions).
#37653 support `default impl` for specialization
this commit implements the first step of the `default impl` feature:
> all items in a `default impl` are (implicitly) `default` and hence
> specializable.
In order to test this feature I've copied all the tests provided for the
`default` method implementation (in run-pass/specialization and
compile-fail/specialization directories) and moved the `default` keyword
from the item to the impl.
See [referenced](https://github.com/rust-lang/rust/issues/37653) issue for further info
r? @aturon
this commit implements the first step of the `default impl` feature:
all items in a `default impl` are (implicitly) `default` and hence
specializable.
In order to test this feature I've copied all the tests provided for the
`default` method implementation (in run-pass/specialization and
compile-fail/specialization directories) and moved the `default` keyword
from the item to the impl.
See referenced issue for further info
Use proper span for tuple index parsed as float
Fix diagnostic suggestion from:
```rust
help: try parenthesizing the first index
| (1, (2, 3)).((1, (2, 3)).1).1;
```
to the correct:
```rust
help: try parenthesizing the first index
| ((1, (2, 3)).1).1;
```
Fix#41081.
