Parse & reject postfix operators after casts
This adds an explicit error messages for when parsing `x as Type[0]` or similar expressions. Our add an extra parse case for parsing any postfix operator (dot, indexing, method calls, await) that triggers directly after parsing `as` expressions.
My friend and I worked on this together, but they're still deciding on a github username and thus I'm submitting this for both of us.
It will immediately error out, but will also provide the rest of the parser with a useful parse tree to deal with.
There's one decision we made in how this produces the parse tree. In the situation `&x as T[0]`, one could imagine this parsing as either `&((x as T)[0])` or `((&x) as T)[0]`. We chose the latter for ease of implementation, and as it seemed the most intuitive.
Feedback welcome! This is our first change to the parser section, and it might be completely horrible.
Fixes#35813.
When encountering an Item in a pat context, point at the item def
```
error[E0308]: mismatched types
--> $DIR/const-in-struct-pat.rs:8:17
|
LL | struct foo;
| ----------- `foo` defined here
...
LL | let Thing { foo } = t;
| ^^^ expected struct `std::string::String`, found struct `foo`
|
= note: `foo` is interpreted as a unit struct, not a new binding
help: you can bind the struct field to a different name
|
LL | let Thing { foo: other_foo } = t;
| ^^^^^^^^^^^^^^
```
```
error[E0308]: mismatched types
--> $DIR/const.rs:14:9
|
LL | const FOO: Foo = Foo{bar: 5};
| ----------------------------- constant defined here
...
LL | FOO => {},
| ^^^
| |
| expected `&Foo`, found struct `Foo`
| `FOO` is interpreted as a constant, not a new binding
| help: use different name to introduce a new binding: `other_foo`
```
Fix#55631, fix#48062, cc #42876.
`delay_span_bug` when codegen cannot select obligation
Fix#69602, introduced in #60126 by letting the compiler continue past
type checking after encountering errors.
even more clippy cleanups
* Don't pass &mut where immutable reference (&) is sufficient (clippy::unnecessary_mut_passed)
* Use more efficient &&str to String conversion (clippy::inefficient_to_string)
* Don't always eval arguments inside .expect(), use unwrap_or_else and closure. (clippy::expect_fun_call)
* Use righthand '&' instead of lefthand "ref". (clippy::toplevel_ref_arg)
* Use simple 'for i in x' loops instead of 'while let Some(i) = x.next()' loops on iterators. (clippy::while_let_on_iterator)
* Const items have by default a static lifetime, there's no need to annotate it. (clippy::redundant_static_lifetimes)
* Remove redundant patterns when matching ( x @ _ to x) (clippy::redundant_pattern)
more clippy cleanups
* Don't use .ok() before unwrapping via .expect() on a Result.
* Use .map() to modify data inside Options instead of using .and_then(|x| Some(y))
* Use .as_deref() instead of .as_ref().map(Deref::deref)
* Don't use "if let" bindings to only check a value and not actually bind anything.
* Use single-char patter on {ends,starts}_with and remove clone on copy type.
