Auto merge of #144607 - camsteffen:impl-trait-header-option, r=lcnr

bors · bors · commit cfd46730a610 · 2025-10-18T00:08:18.000Z
Limit impl_trait_header query to only trait impls

Changes `impl_trait_header` to panic on inherent impls intstead of returning None. A few downstream functions are split into option and non-option returning functions. This gets rid of a lot of unwraps where we know we have a trait impl, while there are still some cases where the Option is helpful.

Summary of changes to tcx methods:
* `impl_is_of_trait` (new)
* `impl_trait_header` -&gt; `impl_trait_header`/`impl_opt_trait_header`
* `impl_trait_ref` -&gt; `impl_trait_ref`/`impl_opt_trait_ref`
* `trait_id_of_impl` -&gt; `impl_trait_id`/`impl_opt_trait_id`
diff --git a/clippy_lints/src/derive/derive_ord_xor_partial_ord.rs b/clippy_lints/src/derive/derive_ord_xor_partial_ord.rs
@@ -28,7 +28,7 @@ pub(super) fn check<'tcx>(
                 return;
             }
 
-            let trait_ref = cx.tcx.impl_trait_ref(impl_id).expect("must be a trait implementation");
+            let trait_ref = cx.tcx.impl_trait_ref(impl_id);
 
             // Only care about `impl PartialOrd<Foo> for Foo`
             // For `impl PartialOrd<B> for A, input_types is [A, B]
diff --git a/clippy_lints/src/derive/derived_hash_with_manual_eq.rs b/clippy_lints/src/derive/derived_hash_with_manual_eq.rs
@@ -27,7 +27,7 @@ pub(super) fn check<'tcx>(
                 return;
             }
 
-            let trait_ref = cx.tcx.impl_trait_ref(impl_id).expect("must be a trait implementation");
+            let trait_ref = cx.tcx.impl_trait_ref(impl_id);
 
             // Only care about `impl PartialEq<Foo> for Foo`
             // For `impl PartialEq<B> for A, input_types is [A, B]
diff --git a/clippy_lints/src/fallible_impl_from.rs b/clippy_lints/src/fallible_impl_from.rs
@@ -52,11 +52,9 @@ declare_lint_pass!(FallibleImplFrom => [FALLIBLE_IMPL_FROM]);
 impl<'tcx> LateLintPass<'tcx> for FallibleImplFrom {
     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'_>) {
         // check for `impl From<???> for ..`
-        if let hir::ItemKind::Impl(_) = &item.kind
-            && let Some(impl_trait_ref) = cx.tcx.impl_trait_ref(item.owner_id)
-            && cx
-                .tcx
-                .is_diagnostic_item(sym::From, impl_trait_ref.skip_binder().def_id)
+        if let hir::ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }) = &item.kind
+            && let impl_trait_id = cx.tcx.impl_trait_id(item.owner_id)
+            && cx.tcx.is_diagnostic_item(sym::From, impl_trait_id)
         {
             lint_impl_body(cx, item.owner_id, item.span);
         }
diff --git a/clippy_lints/src/from_over_into.rs b/clippy_lints/src/from_over_into.rs
@@ -76,8 +76,7 @@ impl<'tcx> LateLintPass<'tcx> for FromOverInto {
             // `impl Into<target_ty> for self_ty`
             && let Some(GenericArgs { args: [GenericArg::Type(target_ty)], .. }) = into_trait_seg.args
             && span_is_local(item.span)
-            && let Some(middle_trait_ref) = cx.tcx.impl_trait_ref(item.owner_id)
-            .map(ty::EarlyBinder::instantiate_identity)
+            && let middle_trait_ref = cx.tcx.impl_trait_ref(item.owner_id).instantiate_identity()
             && cx.tcx.is_diagnostic_item(sym::Into, middle_trait_ref.def_id)
             && !matches!(middle_trait_ref.args.type_at(1).kind(), ty::Alias(ty::Opaque, _))
             && self.msrv.meets(cx, msrvs::RE_REBALANCING_COHERENCE)
diff --git a/clippy_lints/src/implicit_saturating_sub.rs b/clippy_lints/src/implicit_saturating_sub.rs
@@ -339,8 +339,7 @@ fn check_with_condition<'tcx>(
             ExprKind::Path(QPath::TypeRelative(_, name)) => {
                 if name.ident.name == sym::MIN
                     && let Some(const_id) = cx.typeck_results().type_dependent_def_id(cond_num_val.hir_id)
-                    && let Some(impl_id) = cx.tcx.impl_of_assoc(const_id)
-                    && let None = cx.tcx.impl_trait_ref(impl_id) // An inherent impl
+                    && let Some(impl_id) = cx.tcx.inherent_impl_of_assoc(const_id)
                     && cx.tcx.type_of(impl_id).instantiate_identity().is_integral()
                 {
                     print_lint_and_sugg(cx, var_name, expr);
@@ -350,8 +349,7 @@ fn check_with_condition<'tcx>(
                 if let ExprKind::Path(QPath::TypeRelative(_, name)) = func.kind
                     && name.ident.name == sym::min_value
                     && let Some(func_id) = cx.typeck_results().type_dependent_def_id(func.hir_id)
-                    && let Some(impl_id) = cx.tcx.impl_of_assoc(func_id)
-                    && let None = cx.tcx.impl_trait_ref(impl_id) // An inherent impl
+                    && let Some(impl_id) = cx.tcx.inherent_impl_of_assoc(func_id)
                     && cx.tcx.type_of(impl_id).instantiate_identity().is_integral()
                 {
                     print_lint_and_sugg(cx, var_name, expr);
diff --git a/clippy_lints/src/methods/suspicious_splitn.rs b/clippy_lints/src/methods/suspicious_splitn.rs
@@ -10,8 +10,7 @@ use super::SUSPICIOUS_SPLITN;
 pub(super) fn check(cx: &LateContext<'_>, method_name: Symbol, expr: &Expr<'_>, self_arg: &Expr<'_>, count: u128) {
     if count <= 1
         && let Some(call_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id)
-        && let Some(impl_id) = cx.tcx.impl_of_assoc(call_id)
-        && cx.tcx.impl_trait_ref(impl_id).is_none()
+        && let Some(impl_id) = cx.tcx.inherent_impl_of_assoc(call_id)
         && let self_ty = cx.tcx.type_of(impl_id).instantiate_identity()
         && (self_ty.is_slice() || self_ty.is_str())
     {
diff --git a/clippy_lints/src/missing_inline.rs b/clippy_lints/src/missing_inline.rs
@@ -167,7 +167,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingInline {
         let container_id = assoc_item.container_id(cx.tcx);
         let trait_def_id = match assoc_item.container {
             AssocContainer::Trait => Some(container_id),
-            AssocContainer::TraitImpl(_) => cx.tcx.impl_trait_ref(container_id).map(|t| t.skip_binder().def_id),
+            AssocContainer::TraitImpl(_) => Some(cx.tcx.impl_trait_id(container_id)),
             AssocContainer::InherentImpl => None,
         };
 
diff --git a/clippy_lints/src/non_canonical_impls.rs b/clippy_lints/src/non_canonical_impls.rs
@@ -6,7 +6,7 @@ use rustc_errors::Applicability;
 use rustc_hir::def_id::DefId;
 use rustc_hir::{Block, Body, Expr, ExprKind, ImplItem, ImplItemKind, Item, ItemKind, LangItem, UnOp};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::ty::{EarlyBinder, TyCtxt, TypeckResults};
+use rustc_middle::ty::{TyCtxt, TypeckResults};
 use rustc_session::impl_lint_pass;
 use rustc_span::sym;
 use rustc_span::symbol::kw;
@@ -173,10 +173,11 @@ impl LateLintPass<'_> for NonCanonicalImpls {
                     }
                 });
 
+            let trait_impl = cx.tcx.impl_trait_ref(item.owner_id).skip_binder();
+
             match trait_ {
                 Trait::Clone => {
                     if let Some(copy_trait) = self.copy_trait
-                        && let Some(trait_impl) = cx.tcx.impl_trait_ref(item.owner_id).map(EarlyBinder::skip_binder)
                         && implements_trait(cx, trait_impl.self_ty(), copy_trait, &[])
                     {
                         for (assoc, _, block) in assoc_fns {
@@ -185,10 +186,9 @@ impl LateLintPass<'_> for NonCanonicalImpls {
                     }
                 },
                 Trait::PartialOrd => {
-                    if let Some(trait_impl) = cx.tcx.impl_trait_ref(item.owner_id).map(EarlyBinder::skip_binder)
-                        // If `Self` and `Rhs` are not the same type, then a corresponding `Ord` impl is not possible,
-                        // since it doesn't have an `Rhs`
-                        && let [lhs, rhs] = trait_impl.args.as_slice()
+                    // If `Self` and `Rhs` are not the same type, then a corresponding `Ord` impl is not possible,
+                    // since it doesn't have an `Rhs`
+                    if let [lhs, rhs] = trait_impl.args.as_slice()
                         && lhs == rhs
                         && let Some(ord_trait) = self.ord_trait
                         && implements_trait(cx, trait_impl.self_ty(), ord_trait, &[])
diff --git a/clippy_lints/src/non_send_fields_in_send_ty.rs b/clippy_lints/src/non_send_fields_in_send_ty.rs
@@ -87,7 +87,7 @@ impl<'tcx> LateLintPass<'tcx> for NonSendFieldInSendTy {
             && let Some(trait_id) = of_trait.trait_ref.trait_def_id()
             && send_trait == trait_id
             && of_trait.polarity == ImplPolarity::Positive
-            && let Some(ty_trait_ref) = cx.tcx.impl_trait_ref(item.owner_id)
+            && let ty_trait_ref = cx.tcx.impl_trait_ref(item.owner_id)
             && let self_ty = ty_trait_ref.instantiate_identity().self_ty()
             && let ty::Adt(adt_def, impl_trait_args) = self_ty.kind()
         {
diff --git a/clippy_lints/src/only_used_in_recursion.rs b/clippy_lints/src/only_used_in_recursion.rs
@@ -6,9 +6,9 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::Applicability;
 use rustc_hir::def_id::DefId;
 use rustc_hir::hir_id::HirIdMap;
-use rustc_hir::{Body, Expr, ExprKind, HirId, ImplItem, ImplItemKind, Node, PatKind, TraitItem, TraitItemKind};
+use rustc_hir::{Body, Expr, ExprKind, HirId, ImplItem, ImplItemImplKind, ImplItemKind, Node, PatKind, TraitItem, TraitItemKind};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty::{self, ConstKind, EarlyBinder, GenericArgKind, GenericArgsRef};
+use rustc_middle::ty::{self, ConstKind, GenericArgKind, GenericArgsRef};
 use rustc_session::impl_lint_pass;
 use rustc_span::Span;
 use rustc_span::symbol::{Ident, kw};
@@ -320,15 +320,14 @@ impl<'tcx> LateLintPass<'tcx> for OnlyUsedInRecursion {
             Node::ImplItem(&ImplItem {
                 kind: ImplItemKind::Fn(ref sig, _),
                 owner_id,
+                impl_kind,
                 ..
             }) => {
-                if let Node::Item(item) = cx.tcx.parent_hir_node(owner_id.into())
-                    && let Some(trait_ref) = cx
-                        .tcx
-                        .impl_trait_ref(item.owner_id)
-                        .map(EarlyBinder::instantiate_identity)
-                    && let Some(trait_item_id) = cx.tcx.trait_item_of(owner_id)
+                if let ImplItemImplKind::Trait { trait_item_def_id, .. } = impl_kind
+                    && let Ok(trait_item_id) = trait_item_def_id
                 {
+                    let impl_id = cx.tcx.parent(owner_id.into());
+                    let trait_ref = cx.tcx.impl_trait_ref(impl_id).instantiate_identity();
                     (
                         trait_item_id,
                         FnKind::ImplTraitFn(
diff --git a/clippy_lints/src/return_self_not_must_use.rs b/clippy_lints/src/return_self_not_must_use.rs
@@ -113,10 +113,9 @@ impl<'tcx> LateLintPass<'tcx> for ReturnSelfNotMustUse {
     ) {
         if matches!(kind, FnKind::Method(_, _))
             // We are only interested in methods, not in functions or associated functions.
-            && let Some(impl_def) = cx.tcx.impl_of_assoc(fn_def.to_def_id())
             // We don't want this method to be te implementation of a trait because the
             // `#[must_use]` should be put on the trait definition directly.
-            && cx.tcx.trait_id_of_impl(impl_def).is_none()
+            && cx.tcx.inherent_impl_of_assoc(fn_def.to_def_id()).is_some()
         {
             let hir_id = cx.tcx.local_def_id_to_hir_id(fn_def);
             check_method(cx, decl, fn_def, span, hir_id.expect_owner());
diff --git a/clippy_lints/src/unused_io_amount.rs b/clippy_lints/src/unused_io_amount.rs
@@ -85,9 +85,8 @@ impl<'tcx> LateLintPass<'tcx> for UnusedIoAmount {
     /// get desugared to match.
     fn check_block(&mut self, cx: &LateContext<'tcx>, block: &'tcx hir::Block<'tcx>) {
         let fn_def_id = block.hir_id.owner.to_def_id();
-        if let Some(impl_id) = cx.tcx.impl_of_assoc(fn_def_id)
-            && let Some(trait_id) = cx.tcx.trait_id_of_impl(impl_id)
-        {
+        if let Some(impl_id) = cx.tcx.trait_impl_of_assoc(fn_def_id) {
+            let trait_id = cx.tcx.impl_trait_id(impl_id);
             // We don't want to lint inside io::Read or io::Write implementations, as the author has more
             // information about their trait implementation than our lint, see https://github.com/rust-lang/rust-clippy/issues/4836
             if let Some(trait_name) = cx.tcx.get_diagnostic_name(trait_id)
diff --git a/clippy_lints/src/use_self.rs b/clippy_lints/src/use_self.rs
@@ -10,7 +10,7 @@ use rustc_hir::def_id::LocalDefId;
 use rustc_hir::intravisit::{InferKind, Visitor, VisitorExt, walk_ty};
 use rustc_hir::{
     self as hir, AmbigArg, Expr, ExprKind, FnRetTy, FnSig, GenericArgsParentheses, GenericParamKind, HirId, Impl,
-    ImplItemKind, Item, ItemKind, Pat, PatExpr, PatExprKind, PatKind, Path, QPath, Ty, TyKind,
+    ImplItemImplKind, ImplItemKind, Item, ItemKind, Pat, PatExpr, PatExprKind, PatKind, Path, QPath, Ty, TyKind,
 };
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::Ty as MiddleTy;
@@ -142,13 +142,14 @@ impl<'tcx> LateLintPass<'tcx> for UseSelf {
         // We want to skip types in trait `impl`s that aren't declared as `Self` in the trait
         // declaration. The collection of those types is all this method implementation does.
         if let ImplItemKind::Fn(FnSig { decl, .. }, ..) = impl_item.kind
+            && let ImplItemImplKind::Trait { .. } = impl_item.impl_kind
             && let Some(&mut StackItem::Check {
                 impl_id,
                 ref mut types_to_skip,
                 ..
             }) = self.stack.last_mut()
-            && let Some(impl_trait_ref) = cx.tcx.impl_trait_ref(impl_id)
         {
+            let impl_trait_ref = cx.tcx.impl_trait_ref(impl_id);
             // `self_ty` is the semantic self type of `impl <trait> for <type>`. This cannot be
             // `Self`.
             let self_ty = impl_trait_ref.instantiate_identity().self_ty();
diff --git a/clippy_lints_internal/src/msrv_attr_impl.rs b/clippy_lints_internal/src/msrv_attr_impl.rs
@@ -26,10 +26,7 @@ impl LateLintPass<'_> for MsrvAttrImpl {
             items,
             ..
         }) = &item.kind
-            && let Some(trait_ref) = cx
-                .tcx
-                .impl_trait_ref(item.owner_id)
-                .map(EarlyBinder::instantiate_identity)
+            && let trait_ref = cx.tcx.impl_trait_ref(item.owner_id).instantiate_identity()
             && internal_paths::EARLY_LINT_PASS.matches(cx, trait_ref.def_id)
             && let ty::Adt(self_ty_def, _) = trait_ref.self_ty().kind()
             && self_ty_def.is_struct()

Original file line number	Diff line number	Diff line change
`@@ -28,7 +28,7 @@ pub(super) fn check<'tcx>(`
`28`	`28`	`return;`
`29`	`29`	`}`
`30`	`30`
`31`		`- let trait_ref = cx.tcx.impl_trait_ref(impl_id).expect("must be a trait implementation");`
	`31`	`+ let trait_ref = cx.tcx.impl_trait_ref(impl_id);`
`32`	`32`
`33`	`33`	// Only care about `impl PartialOrd<Foo> for Foo`
`34`	`34`	// For `impl PartialOrd<B> for A, input_types is [A, B]
Original file line number	Diff line number	Diff line change
`@@ -27,7 +27,7 @@ pub(super) fn check<'tcx>(`
`27`	`27`	`return;`
`28`	`28`	`}`
`29`	`29`
`30`		`- let trait_ref = cx.tcx.impl_trait_ref(impl_id).expect("must be a trait implementation");`
	`30`	`+ let trait_ref = cx.tcx.impl_trait_ref(impl_id);`
`31`	`31`
`32`	`32`	// Only care about `impl PartialEq<Foo> for Foo`
`33`	`33`	// For `impl PartialEq<B> for A, input_types is [A, B]
Original file line number	Diff line number	Diff line change
`@@ -87,7 +87,7 @@ impl<'tcx> LateLintPass<'tcx> for NonSendFieldInSendTy {`
`87`	`87`	`&& let Some(trait_id) = of_trait.trait_ref.trait_def_id()`
`88`	`88`	`&& send_trait == trait_id`
`89`	`89`	`&& of_trait.polarity == ImplPolarity::Positive`
`90`		`- && let Some(ty_trait_ref) = cx.tcx.impl_trait_ref(item.owner_id)`
	`90`	`+ && let ty_trait_ref = cx.tcx.impl_trait_ref(item.owner_id)`
`91`	`91`	`&& let self_ty = ty_trait_ref.instantiate_identity().self_ty()`
`92`	`92`	`&& let ty::Adt(adt_def, impl_trait_args) = self_ty.kind()`
`93`	`93`	`{`