This now reuses `fn discriminant_ty` in project, removing
some code duplication. Doing so made me realize that
we previously had a disagreement about the discriminant
type of generators, with MIR using `u32` and codegen and
trait selection using `i32`.
We now always use `u32`.
Note that the output of `unpretty-debug.stdout` has changed. In that
test the hash values are normalized from a symbol numbers to small
numbers like "0#0" and "0#1". The increase in the number of static
symbols must have caused the original numbers to contain more digits,
resulting in different pretty-printing prior to normalization.
This is a re-attempt of #72389 (which was reverted in #73594)
Instead of using `ExpnKind::Desugaring` to represent operators, this PR
checks the lang item directly.
Fixes#70718
This commit allows making associated items (e.g. associated functions
and types) into lang items via the `#[lang]` attribute. This allows such
items to be accessed directly, rather than by iterating over the parent
item's associated items.
I've added `FnOnce::Output` as a lang item, and updated one old usage to
use the new lang item. The remaining uses can be updated separately.
This initial version only injects counters at the top of each function.
Rust Coverage will require injecting additional counters at each
conditional code branch.
