Auto merge of #132460 - lcnr:questionable-uwu, r=compiler-errors

Use `TypingMode` throughout the compiler instead of `ParamEnv`

Hopefully the biggest single PR as part of https://github.com/rust-lang/types-team/issues/128.

## `infcx.typing_env` while defining opaque types

I don't know how'll be able to correctly handle opaque types when using something taking a `TypingEnv` while defining opaque types. To correctly handle the opaques we need to be able to pass in the current `opaque_type_storage` and return constraints, i.e. we need to use a proper canonical query. We should migrate all the queries used during HIR typeck and borrowck where this matters to proper canonical queries. This is

## `layout_of` and `Reveal::All`

We convert the `ParamEnv` to `Reveal::All` right at the start of the `layout_of` query, so I've changed callers of `layout_of` to already use a post analysis `TypingEnv` when encountering it.

https://github.com/rust-lang/rust/blob/ca87b535a05097df6abbe2a031b057de2cefac5b/compiler/rustc_ty_utils/src/layout.rs#L51

## `Ty::is_[unpin|sized|whatever]`

I haven't migrated `fn is_item_raw` to use `TypingEnv`, will do so in a followup PR, this should significantly reduce the amount of `typing_env.param_env`. At some point there will probably be zero such uses as using the type system while ignoring the `typing_mode` is incorrect.

## `MirPhase` and phase-transitions

When inside of a MIR-body, we can mostly use its `MirPhase` to figure out the right `typing_mode`. This does not work during phase transitions, most notably when transitioning from `Analysis` to `Runtime`:

https://github.com/rust-lang/rust/blob/dae7ac133b9eda152784c075facb31a6688c92b1/compiler/rustc_mir_transform/src/lib.rs#L606-L625

All these passes still run with `MirPhase::Analysis`, but we should only use `Reveal::All` once we're run the `RevealAll` pass. This required me to manually construct the right `TypingEnv` in all these passes. Given that it feels somewhat easy to accidentally miss this going forward, I would maybe like to change `Body::phase` to an `Option` and replace it at the start of phase transitions. This then makes it clear that the MIR is currently in a weird state.

r? `@ghost`

1 files changed, 5 insertions, 4 deletions

diff --git a/compiler/rustc_traits/src/codegen.rs b/compiler/rustc_traits/src/codegen.rs
index d8c1c50d79a..57225df0819 100644
--- a/compiler/rustc_traits/src/codegen.rs
+++ b/compiler/rustc_traits/src/codegen.rs
@@ -6,7 +6,7 @@
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::bug;
 use rustc_middle::traits::CodegenObligationError;
-use rustc_middle::ty::{self, TyCtxt, TypeVisitableExt, TypingMode};
+use rustc_middle::ty::{self, PseudoCanonicalInput, TyCtxt, TypeVisitableExt};
 use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
 use rustc_trait_selection::traits::{
     ImplSource, Obligation, ObligationCause, ObligationCtxt, ScrubbedTraitError, SelectionContext,
@@ -23,14 +23,15 @@ use tracing::debug;
 /// This also expects that `trait_ref` is fully normalized.
 pub(crate) fn codegen_select_candidate<'tcx>(
     tcx: TyCtxt<'tcx>,
-    (param_env, trait_ref): (ty::ParamEnv<'tcx>, ty::TraitRef<'tcx>),
+    key: PseudoCanonicalInput<'tcx, ty::TraitRef<'tcx>>,
 ) -> Result<&'tcx ImplSource<'tcx, ()>, CodegenObligationError> {
+    let PseudoCanonicalInput { typing_env, value: trait_ref } = key;
     // We expect the input to be fully normalized.
-    debug_assert_eq!(trait_ref, tcx.normalize_erasing_regions(param_env, trait_ref));
+    debug_assert_eq!(trait_ref, tcx.normalize_erasing_regions(typing_env, trait_ref));
 
     // Do the initial selection for the obligation. This yields the
     // shallow result we are looking for -- that is, what specific impl.
-    let infcx = tcx.infer_ctxt().ignoring_regions().build(TypingMode::from_param_env(param_env));
+    let (infcx, param_env) = tcx.infer_ctxt().ignoring_regions().build_with_typing_env(typing_env);
     let mut selcx = SelectionContext::new(&infcx);
 
     let obligation_cause = ObligationCause::dummy();