Rollup merge of rust-lang#152136 - eggyal:consolidate-type-const-checks, r=BoxyUwU

Consolidate type const checks on `tcx.is_type_const`

A little bit of cleanup; explanation can be found in the reporting issue.

Fixes rust-lang#152124
r? BoxyUwU

Author: JonathanBrouwer

compiler/rustc_hir_analysis/src/check/check.rs

@@ -923,7 +923,7 @@ pub(crate) fn check_item_type(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Result<(),
                 );
                 check_where_clauses(wfcx, def_id);
 
-                if find_attr!(tcx.get_all_attrs(def_id), AttributeKind::TypeConst(_)) {
+                if tcx.is_type_const(def_id.into()) {
                     wfcheck::check_type_const(wfcx, def_id, ty, true)?;
                 }
                 Ok(())

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -6,10 +6,9 @@ use hir::def_id::{DefId, DefIdMap, LocalDefId};
 use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
 use rustc_errors::codes::*;
 use rustc_errors::{Applicability, ErrorGuaranteed, MultiSpan, pluralize, struct_span_code_err};
-use rustc_hir::attrs::AttributeKind;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::intravisit::VisitorExt;
-use rustc_hir::{self as hir, AmbigArg, GenericParamKind, ImplItemKind, find_attr, intravisit};
+use rustc_hir::{self as hir, AmbigArg, GenericParamKind, ImplItemKind, intravisit};
 use rustc_infer::infer::{self, BoundRegionConversionTime, InferCtxt, TyCtxtInferExt};
 use rustc_infer::traits::util;
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
@@ -2051,12 +2050,8 @@ fn compare_type_const<'tcx>(
     impl_const_item: ty::AssocItem,
     trait_const_item: ty::AssocItem,
 ) -> Result<(), ErrorGuaranteed> {
-    let impl_is_type_const =
-        find_attr!(tcx.get_all_attrs(impl_const_item.def_id), AttributeKind::TypeConst(_));
-    let trait_type_const_span = find_attr!(
-        tcx.get_all_attrs(trait_const_item.def_id),
-        AttributeKind::TypeConst(sp) => *sp
-    );
+    let impl_is_type_const = tcx.is_type_const(impl_const_item.def_id);
+    let trait_type_const_span = tcx.type_const_span(trait_const_item.def_id);
 
     if let Some(trait_type_const_span) = trait_type_const_span
         && !impl_is_type_const

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -953,7 +953,7 @@ pub(crate) fn check_associated_item(
                 wfcx.register_wf_obligation(span, loc, ty.into());
 
                 let has_value = item.defaultness(tcx).has_value();
-                if find_attr!(tcx.get_all_attrs(def_id), AttributeKind::TypeConst(_)) {
+                if tcx.is_type_const(def_id.into()) {
                     check_type_const(wfcx, def_id, ty, has_value)?;
                 }
 

compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs

@@ -4,10 +4,9 @@ use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
 use rustc_errors::codes::*;
 use rustc_errors::struct_span_code_err;
 use rustc_hir as hir;
-use rustc_hir::attrs::AttributeKind;
+use rustc_hir::PolyTraitRef;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{CRATE_DEF_ID, DefId};
-use rustc_hir::{PolyTraitRef, find_attr};
 use rustc_middle::bug;
 use rustc_middle::ty::{
     self as ty, IsSuggestable, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitableExt,
@@ -603,10 +602,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                         });
 
                         if let ty::AssocTag::Const = assoc_tag
-                            && !find_attr!(
-                                self.tcx().get_all_attrs(assoc_item.def_id),
-                                AttributeKind::TypeConst(_)
-                            )
+                            && !self.tcx().is_type_const(assoc_item.def_id)
                         {
                             if tcx.features().min_generic_const_args() {
                                 let mut err = self.dcx().struct_span_err(

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -28,10 +28,9 @@ use rustc_errors::codes::*;
 use rustc_errors::{
     Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed, FatalError, struct_span_code_err,
 };
-use rustc_hir::attrs::AttributeKind;
 use rustc_hir::def::{CtorKind, CtorOf, DefKind, Res};
 use rustc_hir::def_id::{DefId, LocalDefId};
-use rustc_hir::{self as hir, AnonConst, GenericArg, GenericArgs, HirId, find_attr};
+use rustc_hir::{self as hir, AnonConst, GenericArg, GenericArgs, HirId};
 use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
 use rustc_infer::traits::DynCompatibilityViolation;
 use rustc_macros::{TypeFoldable, TypeVisitable};
@@ -1423,7 +1422,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             LowerTypeRelativePathMode::Const,
         )? {
             TypeRelativePath::AssocItem(def_id, args) => {
-                if !find_attr!(self.tcx().get_all_attrs(def_id), AttributeKind::TypeConst(_)) {
+                if !self.tcx().is_type_const(def_id) {
                     let mut err = self.dcx().struct_span_err(
                         span,
                         "use of trait associated const without `#[type_const]`",
@@ -1896,7 +1895,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             ty::AssocTag::Const,
         ) {
             Ok((item_def_id, item_args)) => {
-                if !find_attr!(self.tcx().get_all_attrs(item_def_id), AttributeKind::TypeConst(_)) {
+                if !self.tcx().is_type_const(item_def_id) {
                     let mut err = self.dcx().struct_span_err(
                         span,
                         "use of `const` in the type system without `#[type_const]`",

compiler/rustc_hir_analysis/src/lib.rs

@@ -85,12 +85,9 @@ mod variance;
 
 pub use errors::NoVariantNamed;
 use rustc_abi::{CVariadicStatus, ExternAbi};
-use rustc_hir::attrs::AttributeKind;
+use rustc_hir as hir;
 use rustc_hir::def::DefKind;
 use rustc_hir::lints::DelayedLint;
-use rustc_hir::{
-    find_attr, {self as hir},
-};
 use rustc_middle::mir::interpret::GlobalId;
 use rustc_middle::query::Providers;
 use rustc_middle::ty::{Const, Ty, TyCtxt};
@@ -238,7 +235,7 @@ pub fn check_crate(tcx: TyCtxt<'_>) {
             }
             DefKind::Const
                 if !tcx.generics_of(item_def_id).own_requires_monomorphization()
-                    && !find_attr!(tcx.get_all_attrs(item_def_id), AttributeKind::TypeConst(_)) =>
+                    && !tcx.is_type_const(item_def_id.into()) =>
             {
                 // FIXME(generic_const_items): Passing empty instead of identity args is fishy but
                 //                             seems to be fine for now. Revisit this!

compiler/rustc_middle/src/ty/context.rs

@@ -1886,10 +1886,15 @@ impl<'tcx> TyCtxt<'tcx> {
         self.is_lang_item(self.parent(def_id), LangItem::AsyncDropInPlace)
     }
 
+    pub fn type_const_span(self, def_id: DefId) -> Option<Span> {
+        matches!(self.def_kind(def_id), DefKind::Const | DefKind::AssocConst)
+            .then(|| find_attr!(self.get_all_attrs(def_id), AttributeKind::TypeConst(sp) => *sp))
+            .flatten()
+    }
+
     /// Check if the given `def_id` is a const with the `#[type_const]` attribute.
     pub fn is_type_const(self, def_id: DefId) -> bool {
-        matches!(self.def_kind(def_id), DefKind::Const | DefKind::AssocConst)
-            && find_attr!(self.get_all_attrs(def_id), AttributeKind::TypeConst(_))
+        self.type_const_span(def_id).is_some()
     }
 
     /// Returns the movability of the coroutine of `def_id`, or panics

compiler/rustc_trait_selection/src/traits/dyn_compatibility.rs

@@ -7,10 +7,9 @@
 use std::ops::ControlFlow;
 
 use rustc_errors::FatalError;
-use rustc_hir::attrs::AttributeKind;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::DefId;
-use rustc_hir::{self as hir, LangItem, find_attr};
+use rustc_hir::{self as hir, LangItem};
 use rustc_middle::query::Providers;
 use rustc_middle::ty::{
     self, EarlyBinder, GenericArgs, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable,
@@ -333,7 +332,7 @@ pub fn dyn_compatibility_violations_for_assoc_item(
             if tcx.features().min_generic_const_args() {
                 if !tcx.generics_of(item.def_id).is_own_empty() {
                     errors.push(AssocConstViolation::Generic);
-                } else if !find_attr!(tcx.get_all_attrs(item.def_id), AttributeKind::TypeConst(_)) {
+                } else if !tcx.is_type_const(item.def_id) {
                     errors.push(AssocConstViolation::NonType);
                 }