Remove is_normalizable (#14717)

Supersedes #12550

`layout_of` no longer contains a `delay_bug` so there's no need for this
anymore.

changelog: None

Author: dswij

clippy_lints/src/casts/manual_dangling_ptr.rs

@@ -1,6 +1,5 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::source::SpanRangeExt;
-use clippy_utils::ty::is_normalizable;
 use clippy_utils::{expr_or_init, match_def_path, path_def_id, paths, std_or_core};
 use rustc_ast::LitKind;
 use rustc_errors::Applicability;
@@ -71,12 +70,10 @@ fn is_literal_aligned(cx: &LateContext<'_>, lit: &Spanned<LitKind>, to: &Ty<'_>)
         return false;
     }
     let to_mid_ty = cx.typeck_results().node_type(to.hir_id);
-    is_normalizable(cx, cx.param_env, to_mid_ty)
-        && cx
-            .tcx
-            .layout_of(cx.typing_env().as_query_input(to_mid_ty))
-            .is_ok_and(|layout| {
-                let align = u128::from(layout.align.abi.bytes());
-                u128::from(val) <= align
-            })
+    cx.tcx
+        .layout_of(cx.typing_env().as_query_input(to_mid_ty))
+        .is_ok_and(|layout| {
+            let align = u128::from(layout.align.abi.bytes());
+            u128::from(val) <= align
+        })
 }

clippy_lints/src/transmute/eager_transmute.rs

@@ -1,5 +1,4 @@
 use clippy_utils::diagnostics::span_lint_and_then;
-use clippy_utils::ty::is_normalizable;
 use clippy_utils::{eq_expr_value, path_to_local, sym};
 use rustc_abi::WrappingRange;
 use rustc_errors::Applicability;
@@ -84,8 +83,6 @@ pub(super) fn check<'tcx>(
         && path.ident.name == sym::then_some
         && is_local_with_projections(transmutable)
         && binops_with_local(cx, transmutable, receiver)
-        && is_normalizable(cx, cx.param_env, from_ty)
-        && is_normalizable(cx, cx.param_env, to_ty)
         // we only want to lint if the target type has a niche that is larger than the one of the source type
         // e.g. `u8` to `NonZero<u8>` should lint, but `NonZero<u8>` to `u8` should not
         && let Ok(from_layout) = cx.tcx.layout_of(cx.typing_env().as_query_input(from_ty))

clippy_lints/src/zero_sized_map_values.rs

@@ -1,5 +1,5 @@
 use clippy_utils::diagnostics::span_lint_and_help;
-use clippy_utils::ty::{is_normalizable, is_type_diagnostic_item, ty_from_hir_ty};
+use clippy_utils::ty::{is_type_diagnostic_item, ty_from_hir_ty};
 use rustc_hir::{self as hir, AmbigArg, HirId, ItemKind, Node};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::layout::LayoutOf as _;
@@ -54,8 +54,6 @@ impl LateLintPass<'_> for ZeroSizedMapValues {
             // Fixes https://github.com/rust-lang/rust-clippy/issues/7447 because of
             // https://github.com/rust-lang/rust/blob/master/compiler/rustc_middle/src/ty/sty.rs#L968
             && !ty.has_escaping_bound_vars()
-            // Do this to prevent `layout_of` crashing, being unable to fully normalize `ty`.
-            && is_normalizable(cx, cx.param_env, ty)
             && let Ok(layout) = cx.layout_of(ty)
             && layout.is_zst()
         {

clippy_utils/src/ty/mod.rs

@@ -20,7 +20,7 @@ use rustc_middle::traits::EvaluationResult;
 use rustc_middle::ty::layout::ValidityRequirement;
 use rustc_middle::ty::{
     self, AdtDef, AliasTy, AssocItem, AssocTag, Binder, BoundRegion, FnSig, GenericArg, GenericArgKind, GenericArgsRef,
-    GenericParamDefKind, IntTy, ParamEnv, Region, RegionKind, TraitRef, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable,
+    GenericParamDefKind, IntTy, Region, RegionKind, TraitRef, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable,
     TypeVisitableExt, TypeVisitor, UintTy, Upcast, VariantDef, VariantDiscr,
 };
 use rustc_span::symbol::Ident;
@@ -359,56 +359,6 @@ pub fn is_must_use_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
     }
 }
 
-// FIXME: Per https://doc.rust-lang.org/nightly/nightly-rustc/rustc_trait_selection/infer/at/struct.At.html#method.normalize
-// this function can be removed once the `normalize` method does not panic when normalization does
-// not succeed
-/// Checks if `Ty` is normalizable. This function is useful
-/// to avoid crashes on `layout_of`.
-pub fn is_normalizable<'tcx>(cx: &LateContext<'tcx>, param_env: ParamEnv<'tcx>, ty: Ty<'tcx>) -> bool {
-    is_normalizable_helper(cx, param_env, ty, 0, &mut FxHashMap::default())
-}
-
-fn is_normalizable_helper<'tcx>(
-    cx: &LateContext<'tcx>,
-    param_env: ParamEnv<'tcx>,
-    ty: Ty<'tcx>,
-    depth: usize,
-    cache: &mut FxHashMap<Ty<'tcx>, bool>,
-) -> bool {
-    if let Some(&cached_result) = cache.get(&ty) {
-        return cached_result;
-    }
-    if !cx.tcx.recursion_limit().value_within_limit(depth) {
-        return false;
-    }
-    // Prevent recursive loops by answering `true` to recursive requests with the same
-    // type. This will be adjusted when the outermost call analyzes all the type
-    // components.
-    cache.insert(ty, true);
-    let infcx = cx.tcx.infer_ctxt().build(cx.typing_mode());
-    let cause = ObligationCause::dummy();
-    let result = if infcx.at(&cause, param_env).query_normalize(ty).is_ok() {
-        match ty.kind() {
-            ty::Adt(def, args) => def.variants().iter().all(|variant| {
-                variant
-                    .fields
-                    .iter()
-                    .all(|field| is_normalizable_helper(cx, param_env, field.ty(cx.tcx, args), depth + 1, cache))
-            }),
-            _ => ty.walk().all(|generic_arg| match generic_arg.unpack() {
-                GenericArgKind::Type(inner_ty) if inner_ty != ty => {
-                    is_normalizable_helper(cx, param_env, inner_ty, depth + 1, cache)
-                },
-                _ => true, // if inner_ty == ty, we've already checked it
-            }),
-        }
-    } else {
-        false
-    };
-    cache.insert(ty, result);
-    result
-}
-
 /// Returns `true` if the given type is a non aggregate primitive (a `bool` or `char`, any
 /// integer or floating-point number type).
 ///
@@ -993,9 +943,6 @@ pub fn adt_and_variant_of_res<'tcx>(cx: &LateContext<'tcx>, res: Res) -> Option<
 /// account the layout of type parameters.
 pub fn approx_ty_size<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> u64 {
     use rustc_middle::ty::layout::LayoutOf;
-    if !is_normalizable(cx, cx.param_env, ty) {
-        return 0;
-    }
     match (cx.layout_of(ty).map(|layout| layout.size.bytes()), ty.kind()) {
         (Ok(size), _) => size,
         (Err(_), ty::Tuple(list)) => list.iter().map(|t| approx_ty_size(cx, t)).sum(),