Point at `:` when using it instead of `;`
When triggering type ascription in such a way that we can infer a
statement end was intended, add a suggestion for the change. Always
point out the reason for the expectation of a type is due to type
ascription.
Fix#42057, #41928.
Now there's a way to add suggestions that hide the suggested code when
presented inline, to avoid weird wording when short code snippets are
added at the end.
When there're more than one suggestions in the same diagnostic, they are
displayed in their own block, instead of inline. In order to reduce
confusion, those blocks now display the line number.
Prior to this PR, when we aborted because a "critical pass" failed, we
displayed the number of errors from that critical pass. While that's the
number of errors that caused compilation to abort in *that place*,
that's not what people really want to know. Instead, always report the
total number of errors, and don't bother to track the number of errors
from the last pass that failed.
This changes the compiler driver API to handle errors more smoothly,
and therefore is a compiler-api-[breaking-change].
Fixes#42793.
- 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);
```
