use `TypingEnv` when no `infcx` is available

the behavior of the type system not only depends on the current
assumptions, but also the currentnphase of the compiler. This is
mostly necessary as we need to decide whether and how to reveal
opaque types. We track this via the `TypingMode`.

12 files changed, 77 insertions, 66 deletions

diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
index 130f3cb7c2a..f6366ec3b80 100644
--- a/compiler/rustc_lint/src/builtin.rs
+++ b/compiler/rustc_lint/src/builtin.rs
@@ -2485,7 +2485,7 @@ impl<'tcx> LateLintPass<'tcx> for InvalidValue {
             });
 
             // Check if this ADT has a constrained layout (like `NonNull` and friends).
-            if let Ok(layout) = cx.tcx.layout_of(cx.param_env.and(ty)) {
+            if let Ok(layout) = cx.tcx.layout_of(cx.typing_env().as_query_input(ty)) {
                 if let BackendRepr::Scalar(scalar) | BackendRepr::ScalarPair(scalar, _) =
                     &layout.backend_repr
                 {
@@ -2521,7 +2521,7 @@ impl<'tcx> LateLintPass<'tcx> for InvalidValue {
             ty: Ty<'tcx>,
             init: InitKind,
         ) -> Option<InitError> {
-            let ty = cx.tcx.try_normalize_erasing_regions(cx.param_env, ty).unwrap_or(ty);
+            let ty = cx.tcx.try_normalize_erasing_regions(cx.typing_env(), ty).unwrap_or(ty);
 
             use rustc_type_ir::TyKind::*;
             match ty.kind() {
@@ -2568,7 +2568,7 @@ impl<'tcx> LateLintPass<'tcx> for InvalidValue {
                         let definitely_inhabited = match variant
                             .inhabited_predicate(cx.tcx, *adt_def)
                             .instantiate(cx.tcx, args)
-                            .apply_any_module(cx.tcx, cx.param_env)
+                            .apply_any_module(cx.tcx, cx.typing_env())
                         {
                             // Entirely skip uninhabited variants.
                             Some(false) => return None,
diff --git a/compiler/rustc_lint/src/context.rs b/compiler/rustc_lint/src/context.rs
index aa7ec2659d0..6eec32beab0 100644
--- a/compiler/rustc_lint/src/context.rs
+++ b/compiler/rustc_lint/src/context.rs
@@ -19,7 +19,7 @@ use rustc_middle::bug;
 use rustc_middle::middle::privacy::EffectiveVisibilities;
 use rustc_middle::ty::layout::{LayoutError, LayoutOfHelpers, TyAndLayout};
 use rustc_middle::ty::print::{PrintError, PrintTraitRefExt as _, Printer, with_no_trimmed_paths};
-use rustc_middle::ty::{self, GenericArg, RegisteredTools, Ty, TyCtxt, TypingMode};
+use rustc_middle::ty::{self, GenericArg, RegisteredTools, Ty, TyCtxt, TypingEnv, TypingMode};
 use rustc_session::lint::{
     BuiltinLintDiag, FutureIncompatibleInfo, Level, Lint, LintBuffer, LintExpectationId, LintId,
 };
@@ -708,6 +708,10 @@ impl<'tcx> LateContext<'tcx> {
         TypingMode::non_body_analysis()
     }
 
+    pub fn typing_env(&self) -> TypingEnv<'tcx> {
+        TypingEnv { typing_mode: self.typing_mode(), param_env: self.param_env }
+    }
+
     /// Gets the type-checking results for the current body,
     /// or `None` if outside a body.
     pub fn maybe_typeck_results(&self) -> Option<&'tcx ty::TypeckResults<'tcx>> {
@@ -906,7 +910,7 @@ impl<'tcx> LateContext<'tcx> {
             .find_by_name_and_kind(tcx, Ident::from_str(name), ty::AssocKind::Type, trait_id)
             .and_then(|assoc| {
                 let proj = Ty::new_projection(tcx, assoc.def_id, [self_ty]);
-                tcx.try_normalize_erasing_regions(self.param_env, proj).ok()
+                tcx.try_normalize_erasing_regions(self.typing_env(), proj).ok()
             })
     }
 
@@ -1010,10 +1014,10 @@ impl<'tcx> ty::layout::HasTyCtxt<'tcx> for LateContext<'tcx> {
     }
 }
 
-impl<'tcx> ty::layout::HasParamEnv<'tcx> for LateContext<'tcx> {
+impl<'tcx> ty::layout::HasTypingEnv<'tcx> for LateContext<'tcx> {
     #[inline]
-    fn param_env(&self) -> ty::ParamEnv<'tcx> {
-        self.param_env
+    fn typing_env(&self) -> ty::TypingEnv<'tcx> {
+        self.typing_env()
     }
 }
 
diff --git a/compiler/rustc_lint/src/for_loops_over_fallibles.rs b/compiler/rustc_lint/src/for_loops_over_fallibles.rs
index cf68e41243f..dbc920ea5ae 100644
--- a/compiler/rustc_lint/src/for_loops_over_fallibles.rs
+++ b/compiler/rustc_lint/src/for_loops_over_fallibles.rs
@@ -166,7 +166,7 @@ fn suggest_question_mark<'tcx>(
     }
 
     let ty = args.type_at(0);
-    let infcx = cx.tcx.infer_ctxt().build(cx.typing_mode());
+    let (infcx, param_env) = cx.tcx.infer_ctxt().build_with_typing_env(cx.typing_env());
     let ocx = ObligationCtxt::new(&infcx);
 
     let body_def_id = cx.tcx.hir().body_owner_def_id(body_id);
@@ -175,7 +175,7 @@ fn suggest_question_mark<'tcx>(
 
     ocx.register_bound(
         cause,
-        cx.param_env,
+        param_env,
         // Erase any region vids from the type, which may not be resolved
         infcx.tcx.erase_regions(ty),
         into_iterator_did,
diff --git a/compiler/rustc_lint/src/foreign_modules.rs b/compiler/rustc_lint/src/foreign_modules.rs
index 394ea798d3e..45b188205d2 100644
--- a/compiler/rustc_lint/src/foreign_modules.rs
+++ b/compiler/rustc_lint/src/foreign_modules.rs
@@ -131,7 +131,7 @@ impl ClashingExternDeclarations {
         // Check that the declarations match.
         if !structurally_same_type(
             tcx,
-            tcx.param_env(this_fi.owner_id),
+            ty::TypingEnv::non_body_analysis(tcx, this_fi.owner_id),
             existing_decl_ty,
             this_decl_ty,
             types::CItemKind::Declaration,
@@ -205,18 +205,18 @@ fn get_relevant_span(tcx: TyCtxt<'_>, fi: hir::OwnerId) -> Span {
 /// with the same members (as the declarations shouldn't clash).
 fn structurally_same_type<'tcx>(
     tcx: TyCtxt<'tcx>,
-    param_env: ty::ParamEnv<'tcx>,
+    typing_env: ty::TypingEnv<'tcx>,
     a: Ty<'tcx>,
     b: Ty<'tcx>,
     ckind: types::CItemKind,
 ) -> bool {
     let mut seen_types = UnordSet::default();
-    let result = structurally_same_type_impl(&mut seen_types, tcx, param_env, a, b, ckind);
+    let result = structurally_same_type_impl(&mut seen_types, tcx, typing_env, a, b, ckind);
     if cfg!(debug_assertions) && result {
         // Sanity-check: must have same ABI, size and alignment.
         // `extern` blocks cannot be generic, so we'll always get a layout here.
-        let a_layout = tcx.layout_of(param_env.and(a)).unwrap();
-        let b_layout = tcx.layout_of(param_env.and(b)).unwrap();
+        let a_layout = tcx.layout_of(typing_env.as_query_input(a)).unwrap();
+        let b_layout = tcx.layout_of(typing_env.as_query_input(b)).unwrap();
         assert_eq!(a_layout.backend_repr, b_layout.backend_repr);
         assert_eq!(a_layout.size, b_layout.size);
         assert_eq!(a_layout.align, b_layout.align);
@@ -227,7 +227,7 @@ fn structurally_same_type<'tcx>(
 fn structurally_same_type_impl<'tcx>(
     seen_types: &mut UnordSet<(Ty<'tcx>, Ty<'tcx>)>,
     tcx: TyCtxt<'tcx>,
-    param_env: ty::ParamEnv<'tcx>,
+    typing_env: ty::TypingEnv<'tcx>,
     a: Ty<'tcx>,
     b: Ty<'tcx>,
     ckind: types::CItemKind,
@@ -303,7 +303,7 @@ fn structurally_same_type_impl<'tcx>(
                             structurally_same_type_impl(
                                 seen_types,
                                 tcx,
-                                param_env,
+                                typing_env,
                                 tcx.type_of(a_did).instantiate(tcx, a_gen_args),
                                 tcx.type_of(b_did).instantiate(tcx, b_gen_args),
                                 ckind,
@@ -315,23 +315,23 @@ fn structurally_same_type_impl<'tcx>(
                     // For arrays, we also check the length.
                     a_len == b_len
                         && structurally_same_type_impl(
-                            seen_types, tcx, param_env, *a_ty, *b_ty, ckind,
+                            seen_types, tcx, typing_env, *a_ty, *b_ty, ckind,
                         )
                 }
                 (Slice(a_ty), Slice(b_ty)) => {
-                    structurally_same_type_impl(seen_types, tcx, param_env, *a_ty, *b_ty, ckind)
+                    structurally_same_type_impl(seen_types, tcx, typing_env, *a_ty, *b_ty, ckind)
                 }
                 (RawPtr(a_ty, a_mutbl), RawPtr(b_ty, b_mutbl)) => {
                     a_mutbl == b_mutbl
                         && structurally_same_type_impl(
-                            seen_types, tcx, param_env, *a_ty, *b_ty, ckind,
+                            seen_types, tcx, typing_env, *a_ty, *b_ty, ckind,
                         )
                 }
                 (Ref(_a_region, a_ty, a_mut), Ref(_b_region, b_ty, b_mut)) => {
                     // For structural sameness, we don't need the region to be same.
                     a_mut == b_mut
                         && structurally_same_type_impl(
-                            seen_types, tcx, param_env, *a_ty, *b_ty, ckind,
+                            seen_types, tcx, typing_env, *a_ty, *b_ty, ckind,
                         )
                 }
                 (FnDef(..), FnDef(..)) => {
@@ -346,12 +346,12 @@ fn structurally_same_type_impl<'tcx>(
                     (a_sig.abi, a_sig.safety, a_sig.c_variadic)
                         == (b_sig.abi, b_sig.safety, b_sig.c_variadic)
                         && a_sig.inputs().iter().eq_by(b_sig.inputs().iter(), |a, b| {
-                            structurally_same_type_impl(seen_types, tcx, param_env, *a, *b, ckind)
+                            structurally_same_type_impl(seen_types, tcx, typing_env, *a, *b, ckind)
                         })
                         && structurally_same_type_impl(
                             seen_types,
                             tcx,
-                            param_env,
+                            typing_env,
                             a_sig.output(),
                             b_sig.output(),
                             ckind,
@@ -379,14 +379,14 @@ fn structurally_same_type_impl<'tcx>(
                 // An Adt and a primitive or pointer type. This can be FFI-safe if non-null
                 // enum layout optimisation is being applied.
                 (Adt(..), _) if is_primitive_or_pointer(b) => {
-                    if let Some(a_inner) = types::repr_nullable_ptr(tcx, param_env, a, ckind) {
+                    if let Some(a_inner) = types::repr_nullable_ptr(tcx, typing_env, a, ckind) {
                         a_inner == b
                     } else {
                         false
                     }
                 }
                 (_, Adt(..)) if is_primitive_or_pointer(a) => {
-                    if let Some(b_inner) = types::repr_nullable_ptr(tcx, param_env, b, ckind) {
+                    if let Some(b_inner) = types::repr_nullable_ptr(tcx, typing_env, b, ckind) {
                         b_inner == a
                     } else {
                         false
diff --git a/compiler/rustc_lint/src/if_let_rescope.rs b/compiler/rustc_lint/src/if_let_rescope.rs
index afcfbebc14b..0e874669043 100644
--- a/compiler/rustc_lint/src/if_let_rescope.rs
+++ b/compiler/rustc_lint/src/if_let_rescope.rs
@@ -368,7 +368,7 @@ impl<'tcx, 'a> Visitor<'tcx> for FindSignificantDropper<'tcx, 'a> {
             .cx
             .typeck_results()
             .expr_ty(expr)
-            .has_significant_drop(self.cx.tcx, self.cx.param_env)
+            .has_significant_drop(self.cx.tcx, self.cx.typing_env())
         {
             return ControlFlow::Break(expr.span);
         }
diff --git a/compiler/rustc_lint/src/internal.rs b/compiler/rustc_lint/src/internal.rs
index 2f338f42f19..38c38b59bc5 100644
--- a/compiler/rustc_lint/src/internal.rs
+++ b/compiler/rustc_lint/src/internal.rs
@@ -103,7 +103,8 @@ declare_lint_pass!(QueryStability => [POTENTIAL_QUERY_INSTABILITY, UNTRACKED_QUE
 impl LateLintPass<'_> for QueryStability {
     fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
         let Some((span, def_id, args)) = typeck_results_of_method_fn(cx, expr) else { return };
-        if let Ok(Some(instance)) = ty::Instance::try_resolve(cx.tcx, cx.param_env, def_id, args) {
+        if let Ok(Some(instance)) = ty::Instance::try_resolve(cx.tcx, cx.typing_env(), def_id, args)
+        {
             let def_id = instance.def_id();
             if cx.tcx.has_attr(def_id, sym::rustc_lint_query_instability) {
                 cx.emit_span_lint(POTENTIAL_QUERY_INSTABILITY, span, QueryInstability {
@@ -544,7 +545,7 @@ impl Diagnostics {
     ) {
         // Is the callee marked with `#[rustc_lint_diagnostics]`?
         let Some(inst) =
-            ty::Instance::try_resolve(cx.tcx, cx.param_env, def_id, fn_gen_args).ok().flatten()
+            ty::Instance::try_resolve(cx.tcx, cx.typing_env(), def_id, fn_gen_args).ok().flatten()
         else {
             return;
         };
diff --git a/compiler/rustc_lint/src/let_underscore.rs b/compiler/rustc_lint/src/let_underscore.rs
index abee9ee7869..9e4e8333164 100644
--- a/compiler/rustc_lint/src/let_underscore.rs
+++ b/compiler/rustc_lint/src/let_underscore.rs
@@ -128,7 +128,7 @@ impl<'tcx> LateLintPass<'tcx> for LetUnderscore {
 
             // If the type has a trivial Drop implementation, then it doesn't
             // matter that we drop the value immediately.
-            if !ty.needs_drop(cx.tcx, cx.param_env) {
+            if !ty.needs_drop(cx.tcx, cx.typing_env()) {
                 return;
             }
             // Lint for patterns like `mutex.lock()`, which returns `Result<MutexGuard, _>` as well.
diff --git a/compiler/rustc_lint/src/non_fmt_panic.rs b/compiler/rustc_lint/src/non_fmt_panic.rs
index cf25ec99e67..36b1ff59c67 100644
--- a/compiler/rustc_lint/src/non_fmt_panic.rs
+++ b/compiler/rustc_lint/src/non_fmt_panic.rs
@@ -157,15 +157,17 @@ fn check_panic<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>, arg: &'tc
                 Some(ty_def) if cx.tcx.is_lang_item(ty_def.did(), LangItem::String),
             );
 
-            let infcx = cx.tcx.infer_ctxt().build(cx.typing_mode());
+            let (infcx, param_env) = cx.tcx.infer_ctxt().build_with_typing_env(cx.typing_env());
             let suggest_display = is_str
-                || cx.tcx.get_diagnostic_item(sym::Display).is_some_and(|t| {
-                    infcx.type_implements_trait(t, [ty], cx.param_env).may_apply()
-                });
+                || cx
+                    .tcx
+                    .get_diagnostic_item(sym::Display)
+                    .is_some_and(|t| infcx.type_implements_trait(t, [ty], param_env).may_apply());
             let suggest_debug = !suggest_display
-                && cx.tcx.get_diagnostic_item(sym::Debug).is_some_and(|t| {
-                    infcx.type_implements_trait(t, [ty], cx.param_env).may_apply()
-                });
+                && cx
+                    .tcx
+                    .get_diagnostic_item(sym::Debug)
+                    .is_some_and(|t| infcx.type_implements_trait(t, [ty], param_env).may_apply());
 
             let suggest_panic_any = !is_str && panic == sym::std_panic_macro;
 
diff --git a/compiler/rustc_lint/src/noop_method_call.rs b/compiler/rustc_lint/src/noop_method_call.rs
index 4890a93fa76..76dc96ae00f 100644
--- a/compiler/rustc_lint/src/noop_method_call.rs
+++ b/compiler/rustc_lint/src/noop_method_call.rs
@@ -94,9 +94,9 @@ impl<'tcx> LateLintPass<'tcx> for NoopMethodCall {
 
         let args = cx
             .tcx
-            .normalize_erasing_regions(cx.param_env, cx.typeck_results().node_args(expr.hir_id));
+            .normalize_erasing_regions(cx.typing_env(), cx.typeck_results().node_args(expr.hir_id));
         // Resolve the trait method instance.
-        let Ok(Some(i)) = ty::Instance::try_resolve(cx.tcx, cx.param_env, did, args) else {
+        let Ok(Some(i)) = ty::Instance::try_resolve(cx.tcx, cx.typing_env(), did, args) else {
             return;
         };
         // (Re)check that it implements the noop diagnostic.
diff --git a/compiler/rustc_lint/src/tail_expr_drop_order.rs b/compiler/rustc_lint/src/tail_expr_drop_order.rs
index 89763059877..19763ce1ec5 100644
--- a/compiler/rustc_lint/src/tail_expr_drop_order.rs
+++ b/compiler/rustc_lint/src/tail_expr_drop_order.rs
@@ -103,7 +103,7 @@ impl TailExprDropOrder {
         if matches!(fn_kind, hir::intravisit::FnKind::Closure) {
             for &capture in cx.tcx.closure_captures(def_id) {
                 if matches!(capture.info.capture_kind, ty::UpvarCapture::ByValue)
-                    && capture.place.ty().has_significant_drop(cx.tcx, cx.param_env)
+                    && capture.place.ty().has_significant_drop(cx.tcx, cx.typing_env())
                 {
                     locals.push(capture.var_ident.span);
                 }
@@ -113,7 +113,7 @@ impl TailExprDropOrder {
             if cx
                 .typeck_results()
                 .node_type(param.hir_id)
-                .has_significant_drop(cx.tcx, cx.param_env)
+                .has_significant_drop(cx.tcx, cx.typing_env())
             {
                 locals.push(param.span);
             }
@@ -158,7 +158,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LocalCollector<'a, 'tcx> {
     fn visit_pat(&mut self, pat: &'tcx Pat<'tcx>) {
         if let PatKind::Binding(_binding_mode, id, ident, pat) = pat.kind {
             let ty = self.cx.typeck_results().node_type(id);
-            if ty.has_significant_drop(self.cx.tcx, self.cx.param_env) {
+            if ty.has_significant_drop(self.cx.tcx, self.cx.typing_env()) {
                 self.locals.push(ident.span);
             }
             if let Some(pat) = pat {
@@ -234,7 +234,10 @@ impl<'a, 'tcx> LintTailExpr<'a, 'tcx> {
         if Self::expr_eventually_point_into_local(expr) {
             return false;
         }
-        self.cx.typeck_results().expr_ty(expr).has_significant_drop(self.cx.tcx, self.cx.param_env)
+        self.cx
+            .typeck_results()
+            .expr_ty(expr)
+            .has_significant_drop(self.cx.tcx, self.cx.typing_env())
     }
 }
 
diff --git a/compiler/rustc_lint/src/types.rs b/compiler/rustc_lint/src/types.rs
index be70149b664..2e6cb993842 100644
--- a/compiler/rustc_lint/src/types.rs
+++ b/compiler/rustc_lint/src/types.rs
@@ -613,10 +613,11 @@ pub(crate) fn transparent_newtype_field<'a, 'tcx>(
     tcx: TyCtxt<'tcx>,
     variant: &'a ty::VariantDef,
 ) -> Option<&'a ty::FieldDef> {
-    let param_env = tcx.param_env(variant.def_id);
+    let typing_env = ty::TypingEnv::non_body_analysis(tcx, variant.def_id);
     variant.fields.iter().find(|field| {
         let field_ty = tcx.type_of(field.did).instantiate_identity();
-        let is_1zst = tcx.layout_of(param_env.and(field_ty)).is_ok_and(|layout| layout.is_1zst());
+        let is_1zst =
+            tcx.layout_of(typing_env.as_query_input(field_ty)).is_ok_and(|layout| layout.is_1zst());
         !is_1zst
     })
 }
@@ -624,11 +625,11 @@ pub(crate) fn transparent_newtype_field<'a, 'tcx>(
 /// Is type known to be non-null?
 fn ty_is_known_nonnull<'tcx>(
     tcx: TyCtxt<'tcx>,
-    param_env: ty::ParamEnv<'tcx>,
+    typing_env: ty::TypingEnv<'tcx>,
     ty: Ty<'tcx>,
     mode: CItemKind,
 ) -> bool {
-    let ty = tcx.try_normalize_erasing_regions(param_env, ty).unwrap_or(ty);
+    let ty = tcx.try_normalize_erasing_regions(typing_env, ty).unwrap_or(ty);
 
     match ty.kind() {
         ty::FnPtr(..) => true,
@@ -649,7 +650,7 @@ fn ty_is_known_nonnull<'tcx>(
             def.variants()
                 .iter()
                 .filter_map(|variant| transparent_newtype_field(tcx, variant))
-                .any(|field| ty_is_known_nonnull(tcx, param_env, field.ty(tcx, args), mode))
+                .any(|field| ty_is_known_nonnull(tcx, typing_env, field.ty(tcx, args), mode))
         }
         _ => false,
     }
@@ -659,10 +660,10 @@ fn ty_is_known_nonnull<'tcx>(
 /// If the type passed in was not scalar, returns None.
 fn get_nullable_type<'tcx>(
     tcx: TyCtxt<'tcx>,
-    param_env: ty::ParamEnv<'tcx>,
+    typing_env: ty::TypingEnv<'tcx>,
     ty: Ty<'tcx>,
 ) -> Option<Ty<'tcx>> {
-    let ty = tcx.try_normalize_erasing_regions(param_env, ty).unwrap_or(ty);
+    let ty = tcx.try_normalize_erasing_regions(typing_env, ty).unwrap_or(ty);
 
     Some(match *ty.kind() {
         ty::Adt(field_def, field_args) => {
@@ -679,7 +680,7 @@ fn get_nullable_type<'tcx>(
                     .expect("No non-zst fields in transparent type.")
                     .ty(tcx, field_args)
             };
-            return get_nullable_type(tcx, param_env, inner_field_ty);
+            return get_nullable_type(tcx, typing_env, inner_field_ty);
         }
         ty::Int(ty) => Ty::new_int(tcx, ty),
         ty::Uint(ty) => Ty::new_uint(tcx, ty),
@@ -708,10 +709,10 @@ fn get_nullable_type<'tcx>(
 /// - Does not have the `#[non_exhaustive]` attribute.
 fn is_niche_optimization_candidate<'tcx>(
     tcx: TyCtxt<'tcx>,
-    param_env: ty::ParamEnv<'tcx>,
+    typing_env: ty::TypingEnv<'tcx>,
     ty: Ty<'tcx>,
 ) -> bool {
-    if tcx.layout_of(param_env.and(ty)).is_ok_and(|layout| !layout.is_1zst()) {
+    if tcx.layout_of(typing_env.as_query_input(ty)).is_ok_and(|layout| !layout.is_1zst()) {
         return false;
     }
 
@@ -734,7 +735,7 @@ fn is_niche_optimization_candidate<'tcx>(
 /// `core::ptr::NonNull`, and `#[repr(transparent)]` newtypes.
 pub(crate) fn repr_nullable_ptr<'tcx>(
     tcx: TyCtxt<'tcx>,
-    param_env: ty::ParamEnv<'tcx>,
+    typing_env: ty::TypingEnv<'tcx>,
     ty: Ty<'tcx>,
     ckind: CItemKind,
 ) -> Option<Ty<'tcx>> {
@@ -747,9 +748,9 @@ pub(crate) fn repr_nullable_ptr<'tcx>(
                     let ty1 = field1.ty(tcx, args);
                     let ty2 = field2.ty(tcx, args);
 
-                    if is_niche_optimization_candidate(tcx, param_env, ty1) {
+                    if is_niche_optimization_candidate(tcx, typing_env, ty1) {
                         ty2
-                    } else if is_niche_optimization_candidate(tcx, param_env, ty2) {
+                    } else if is_niche_optimization_candidate(tcx, typing_env, ty2) {
                         ty1
                     } else {
                         return None;
@@ -760,20 +761,20 @@ pub(crate) fn repr_nullable_ptr<'tcx>(
             _ => return None,
         };
 
-        if !ty_is_known_nonnull(tcx, param_env, field_ty, ckind) {
+        if !ty_is_known_nonnull(tcx, typing_env, field_ty, ckind) {
             return None;
         }
 
         // At this point, the field's type is known to be nonnull and the parent enum is Option-like.
         // If the computed size for the field and the enum are different, the nonnull optimization isn't
         // being applied (and we've got a problem somewhere).
-        let compute_size_skeleton = |t| SizeSkeleton::compute(t, tcx, param_env).ok();
+        let compute_size_skeleton = |t| SizeSkeleton::compute(t, tcx, typing_env).ok();
         if !compute_size_skeleton(ty)?.same_size(compute_size_skeleton(field_ty)?) {
             bug!("improper_ctypes: Option nonnull optimization not applied?");
         }
 
         // Return the nullable type this Option-like enum can be safely represented with.
-        let field_ty_layout = tcx.layout_of(param_env.and(field_ty));
+        let field_ty_layout = tcx.layout_of(typing_env.as_query_input(field_ty));
         if field_ty_layout.is_err() && !field_ty.has_non_region_param() {
             bug!("should be able to compute the layout of non-polymorphic type");
         }
@@ -784,10 +785,10 @@ pub(crate) fn repr_nullable_ptr<'tcx>(
                 WrappingRange { start: 0, end }
                     if end == field_ty_scalar.size(&tcx).unsigned_int_max() - 1 =>
                 {
-                    return Some(get_nullable_type(tcx, param_env, field_ty).unwrap());
+                    return Some(get_nullable_type(tcx, typing_env, field_ty).unwrap());
                 }
                 WrappingRange { start: 1, .. } => {
-                    return Some(get_nullable_type(tcx, param_env, field_ty).unwrap());
+                    return Some(get_nullable_type(tcx, typing_env, field_ty).unwrap());
                 }
                 WrappingRange { start, end } => {
                     unreachable!("Unhandled start and end range: ({}, {})", start, end)
@@ -825,7 +826,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
         let field_ty = self
             .cx
             .tcx
-            .try_normalize_erasing_regions(self.cx.param_env, field_ty)
+            .try_normalize_erasing_regions(self.cx.typing_env(), field_ty)
             .unwrap_or(field_ty);
         self.check_type_for_ffi(acc, field_ty)
     }
@@ -988,7 +989,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
                         {
                             // Special-case types like `Option<extern fn()>` and `Result<extern fn(), ()>`
                             if let Some(ty) =
-                                repr_nullable_ptr(self.cx.tcx, self.cx.param_env, ty, self.mode)
+                                repr_nullable_ptr(self.cx.tcx, self.cx.typing_env(), ty, self.mode)
                             {
                                 return self.check_type_for_ffi(acc, ty);
                             }
@@ -1196,7 +1197,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
         if let Some(ty) = self
             .cx
             .tcx
-            .try_normalize_erasing_regions(self.cx.param_env, ty)
+            .try_normalize_erasing_regions(self.cx.typing_env(), ty)
             .unwrap_or(ty)
             .visit_with(&mut ProhibitOpaqueTypes)
             .break_value()
@@ -1220,7 +1221,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
             return;
         }
 
-        let ty = self.cx.tcx.try_normalize_erasing_regions(self.cx.param_env, ty).unwrap_or(ty);
+        let ty = self.cx.tcx.try_normalize_erasing_regions(self.cx.typing_env(), ty).unwrap_or(ty);
 
         // C doesn't really support passing arrays by value - the only way to pass an array by value
         // is through a struct. So, first test that the top level isn't an array, and then
diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs
index 6c13127b04e..5ec920d39f4 100644
--- a/compiler/rustc_lint/src/unused.rs
+++ b/compiler/rustc_lint/src/unused.rs
@@ -272,7 +272,7 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults {
                 || !ty.is_inhabited_from(
                     cx.tcx,
                     cx.tcx.parent_module(expr.hir_id).to_def_id(),
-                    cx.param_env,
+                    cx.typing_env(),
                 )
             {
                 return Some(MustUsePath::Suppressed);
@@ -556,7 +556,7 @@ impl<'tcx> LateLintPass<'tcx> for PathStatements {
         if let hir::StmtKind::Semi(expr) = s.kind {
             if let hir::ExprKind::Path(_) = expr.kind {
                 let ty = cx.typeck_results().expr_ty(expr);
-                if ty.needs_drop(cx.tcx, cx.param_env) {
+                if ty.needs_drop(cx.tcx, cx.typing_env()) {
                     let sub = if let Ok(snippet) = cx.sess().source_map().span_to_snippet(expr.span)
                     {
                         PathStatementDropSub::Suggestion { span: s.span, snippet }