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, 24 insertions, 12 deletions

diff --git a/compiler/rustc_pattern_analysis/src/rustc.rs b/compiler/rustc_pattern_analysis/src/rustc.rs
index 9ea5023064c..936e5235c55 100644
--- a/compiler/rustc_pattern_analysis/src/rustc.rs
+++ b/compiler/rustc_pattern_analysis/src/rustc.rs
@@ -9,6 +9,7 @@ use rustc_index::{Idx, IndexVec};
 use rustc_middle::middle::stability::EvalResult;
 use rustc_middle::mir::{self, Const};
 use rustc_middle::thir::{self, Pat, PatKind, PatRange, PatRangeBoundary};
+use rustc_middle::traits::Reveal;
 use rustc_middle::ty::layout::IntegerExt;
 use rustc_middle::ty::{
     self, FieldDef, OpaqueTypeKey, ScalarInt, Ty, TyCtxt, TypeVisitableExt, VariantDef,
@@ -108,6 +109,17 @@ impl<'p, 'tcx: 'p> fmt::Debug for RustcPatCtxt<'p, 'tcx> {
 }
 
 impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
+    pub fn typing_mode(&self) -> ty::TypingMode<'tcx> {
+        debug_assert_eq!(self.param_env.reveal(), Reveal::UserFacing);
+        // FIXME(#132279): This is inside of a body. If we need to use the `param_env`
+        // and `typing_mode` we should reveal opaques defined by that body.
+        ty::TypingMode::non_body_analysis()
+    }
+
+    pub fn typing_env(&self) -> ty::TypingEnv<'tcx> {
+        ty::TypingEnv { typing_mode: self.typing_mode(), param_env: self.param_env }
+    }
+
     /// Type inference occasionally gives us opaque types in places where corresponding patterns
     /// have more specific types. To avoid inconsistencies as well as detect opaque uninhabited
     /// types, we use the corresponding concrete type if possible.
@@ -139,7 +151,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
     pub fn is_uninhabited(&self, ty: Ty<'tcx>) -> bool {
         !ty.inhabited_predicate(self.tcx).apply_revealing_opaque(
             self.tcx,
-            self.param_env,
+            self.typing_env(),
             self.module,
             &|key| self.reveal_opaque_key(key),
         )
@@ -179,7 +191,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
         variant.fields.iter().map(move |field| {
             let ty = field.ty(self.tcx, args);
             // `field.ty()` doesn't normalize after instantiating.
-            let ty = self.tcx.normalize_erasing_regions(self.param_env, ty);
+            let ty = self.tcx.normalize_erasing_regions(self.typing_env(), ty);
             let ty = self.reveal_opaque_ty(ty);
             (field, ty)
         })
@@ -369,7 +381,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
                         let is_inhabited = v
                             .inhabited_predicate(cx.tcx, *def)
                             .instantiate(cx.tcx, args)
-                            .apply_revealing_opaque(cx.tcx, cx.param_env, cx.module, &|key| {
+                            .apply_revealing_opaque(cx.tcx, cx.typing_env(), cx.module, &|key| {
                                 cx.reveal_opaque_key(key)
                             });
                         // Variants that depend on a disabled unstable feature.
@@ -430,7 +442,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
         match bdy {
             PatRangeBoundary::NegInfinity => MaybeInfiniteInt::NegInfinity,
             PatRangeBoundary::Finite(value) => {
-                let bits = value.eval_bits(self.tcx, self.param_env);
+                let bits = value.eval_bits(self.tcx, self.typing_env());
                 match *ty.kind() {
                     ty::Int(ity) => {
                         let size = Integer::from_int_ty(&self.tcx, ity).size().bits();
@@ -539,7 +551,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
             PatKind::Constant { value } => {
                 match ty.kind() {
                     ty::Bool => {
-                        ctor = match value.try_eval_bool(cx.tcx, cx.param_env) {
+                        ctor = match value.try_eval_bool(cx.tcx, cx.typing_env()) {
                             Some(b) => Bool(b),
                             None => Opaque(OpaqueId::new()),
                         };
@@ -547,7 +559,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
                         arity = 0;
                     }
                     ty::Char | ty::Int(_) | ty::Uint(_) => {
-                        ctor = match value.try_eval_bits(cx.tcx, cx.param_env) {
+                        ctor = match value.try_eval_bits(cx.tcx, cx.typing_env()) {
                             Some(bits) => {
                                 let x = match *ty.kind() {
                                     ty::Int(ity) => {
@@ -564,7 +576,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
                         arity = 0;
                     }
                     ty::Float(ty::FloatTy::F16) => {
-                        ctor = match value.try_eval_bits(cx.tcx, cx.param_env) {
+                        ctor = match value.try_eval_bits(cx.tcx, cx.typing_env()) {
                             Some(bits) => {
                                 use rustc_apfloat::Float;
                                 let value = rustc_apfloat::ieee::Half::from_bits(bits);
@@ -576,7 +588,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
                         arity = 0;
                     }
                     ty::Float(ty::FloatTy::F32) => {
-                        ctor = match value.try_eval_bits(cx.tcx, cx.param_env) {
+                        ctor = match value.try_eval_bits(cx.tcx, cx.typing_env()) {
                             Some(bits) => {
                                 use rustc_apfloat::Float;
                                 let value = rustc_apfloat::ieee::Single::from_bits(bits);
@@ -588,7 +600,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
                         arity = 0;
                     }
                     ty::Float(ty::FloatTy::F64) => {
-                        ctor = match value.try_eval_bits(cx.tcx, cx.param_env) {
+                        ctor = match value.try_eval_bits(cx.tcx, cx.typing_env()) {
                             Some(bits) => {
                                 use rustc_apfloat::Float;
                                 let value = rustc_apfloat::ieee::Double::from_bits(bits);
@@ -600,7 +612,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
                         arity = 0;
                     }
                     ty::Float(ty::FloatTy::F128) => {
-                        ctor = match value.try_eval_bits(cx.tcx, cx.param_env) {
+                        ctor = match value.try_eval_bits(cx.tcx, cx.typing_env()) {
                             Some(bits) => {
                                 use rustc_apfloat::Float;
                                 let value = rustc_apfloat::ieee::Quad::from_bits(bits);
@@ -649,8 +661,8 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
                     }
                     ty::Float(fty) => {
                         use rustc_apfloat::Float;
-                        let lo = lo.as_finite().map(|c| c.eval_bits(cx.tcx, cx.param_env));
-                        let hi = hi.as_finite().map(|c| c.eval_bits(cx.tcx, cx.param_env));
+                        let lo = lo.as_finite().map(|c| c.eval_bits(cx.tcx, cx.typing_env()));
+                        let hi = hi.as_finite().map(|c| c.eval_bits(cx.tcx, cx.typing_env()));
                         match fty {
                             ty::FloatTy::F16 => {
                                 use rustc_apfloat::ieee::Half;