Always exhaustively match on typing mode

[jdonszelmann]

r? @lcnr

Unimplements Eq/PartialEq for TypingMode, adds TypingModeEq for the few cases where we need it (mainly in the query system), and adds a new rustc internal lint to detect cases where we non-exhaustively match on typing mode.

[rustbot]

Some changes occurred in compiler/rustc_passes/src/check_attr.rs

cc @JonathanBrouwer

Some changes occurred to the CTFE machinery

cc @RalfJung, @oli-obk, @lcnr

Some changes occurred to the CTFE / Miri interpreter

cc @rust-lang/miri

Some changes occurred in compiler/rustc_attr_parsing

cc @JonathanBrouwer

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

Some changes occurred in compiler/rustc_hir/src/attrs

cc @JonathanBrouwer

Some changes occurred to constck

cc @fee1-dead

changes to the core type system

cc @lcnr

[rustbot]

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

[rustbot]

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

[rust-log-analyzer]

The job pr-check-2 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

    Checking flate2 v1.1.9
error: you are deriving `Hash` but have implemented `PartialEq` explicitly
   --> compiler/rustc_type_ir/src/infer_ctxt.rs:98:1
    |
 98 | #[derive_where(Clone, Copy, Hash, Debug; I: Interner)]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ in this derive macro expansion
    |
   ::: /cargo/registry/src/index.crates.io-1949cf8c6b5b557f/derive-where-1.6.1/src/lib.rs:567:1
    |
567 | pub fn derive_where_actual(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
    | ------------------------------------------------------------------------------------- in this expansion of `#[derive(::derive_where::DeriveWhere)]`
    |
note: `PartialEq` implemented here
   --> compiler/rustc_type_ir/src/infer_ctxt.rs:105:1
    |
105 | impl<I: Interner> PartialEq for EqTypingMode<I> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#derived_hash_with_manual_eq
    = note: `-D clippy::derived-hash-with-manual-eq` implied by `-D clippy::correctness`
    = help: to override `-D clippy::correctness` add `#[allow(clippy::derived_hash_with_manual_eq)]`