Rollup merge of rust-lang#104728 - WaffleLapkin:require-lang-items-politely, r=compiler-errors

Use `tcx.require_lang_item` instead of unwrapping lang items

I clearly remember esteban telling me that there is `require_lang_item` but he was from a phone atm and I couldn't find it, so I didn't use it. Stumbled on it today, so here we are :)

Author: Manishearth

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -7,7 +7,7 @@ use rustc_errors::{
 };
 use rustc_hir as hir;
 use rustc_hir::intravisit::{walk_block, walk_expr, Visitor};
-use rustc_hir::{AsyncGeneratorKind, GeneratorKind};
+use rustc_hir::{AsyncGeneratorKind, GeneratorKind, LangItem};
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_infer::traits::ObligationCause;
 use rustc_middle::mir::tcx::PlaceTy;
@@ -766,7 +766,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         else { return; };
         // Try to find predicates on *generic params* that would allow copying `ty`
         let infcx = tcx.infer_ctxt().build();
-        let copy_did = infcx.tcx.lang_items().copy_trait().unwrap();
+        let copy_did = infcx.tcx.require_lang_item(LangItem::Copy, Some(span));
         let cause = ObligationCause::new(
             span,
             self.mir_hir_id(),

compiler/rustc_const_eval/src/transform/check_consts/ops.rs

@@ -1,7 +1,7 @@
 //! Concrete error types for all operations which may be invalid in a certain const context.
 
 use hir::def_id::LocalDefId;
-use hir::ConstContext;
+use hir::{ConstContext, LangItem};
 use rustc_errors::{
     error_code, struct_span_err, Applicability, DiagnosticBuilder, ErrorGuaranteed,
 };
@@ -304,7 +304,7 @@ impl<'tcx> NonConstOp<'tcx> for FnCallNonConst<'tcx> {
                     err.span_note(deref_target, "deref defined here");
                 }
 
-                diag_trait(&mut err, self_ty, tcx.lang_items().deref_trait().unwrap());
+                diag_trait(&mut err, self_ty, tcx.require_lang_item(LangItem::Deref, Some(span)));
                 err
             }
             _ if tcx.opt_parent(callee) == tcx.get_diagnostic_item(sym::ArgumentV1Methods) => {

compiler/rustc_const_eval/src/util/call_kind.rs

@@ -3,7 +3,7 @@
 //! context.
 
 use rustc_hir::def_id::DefId;
-use rustc_hir::lang_items;
+use rustc_hir::{lang_items, LangItem};
 use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::{self, AssocItemContainer, DefIdTree, Instance, ParamEnv, Ty, TyCtxt};
 use rustc_span::symbol::Ident;
@@ -26,7 +26,7 @@ impl CallDesugaringKind {
         match self {
             Self::ForLoopIntoIter => tcx.get_diagnostic_item(sym::IntoIterator).unwrap(),
             Self::QuestionBranch | Self::TryBlockFromOutput => {
-                tcx.lang_items().try_trait().unwrap()
+                tcx.require_lang_item(LangItem::Try, None)
             }
             Self::QuestionFromResidual => tcx.get_diagnostic_item(sym::FromResidual).unwrap(),
         }

compiler/rustc_hir_analysis/src/coherence/builtin.rs

@@ -114,7 +114,7 @@ fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
                     traits::ObligationCause::dummy_with_span(field_ty_span),
                     param_env,
                     ty,
-                    tcx.lang_items().copy_trait().unwrap(),
+                    tcx.require_lang_item(LangItem::Copy, Some(span)),
                 ) {
                     let error_predicate = error.obligation.predicate;
                     // Only note if it's not the root obligation, otherwise it's trivial and

compiler/rustc_hir_typeck/src/expr.rs

@@ -1118,7 +1118,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 let lhs_deref_ty_is_sized = self
                     .infcx
                     .type_implements_trait(
-                        self.tcx.lang_items().sized_trait().unwrap(),
+                        self.tcx.require_lang_item(LangItem::Sized, None),
                         [lhs_deref_ty],
                         self.param_env,
                     )

compiler/rustc_middle/src/ty/context.rs

@@ -2293,7 +2293,7 @@ impl<'tcx> TyCtxt<'tcx> {
     /// Given a `ty`, return whether it's an `impl Future<...>`.
     pub fn ty_is_opaque_future(self, ty: Ty<'_>) -> bool {
         let ty::Opaque(def_id, _) = ty.kind() else { return false };
-        let future_trait = self.lang_items().future_trait().unwrap();
+        let future_trait = self.require_lang_item(LangItem::Future, None);
 
         self.explicit_item_bounds(def_id).iter().any(|(predicate, _)| {
             let ty::PredicateKind::Trait(trait_predicate) = predicate.kind().skip_binder() else {

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -11,6 +11,7 @@ use rustc_hir as hir;
 use rustc_hir::def::{self, CtorKind, DefKind, Namespace};
 use rustc_hir::def_id::{DefId, DefIdSet, CRATE_DEF_ID, LOCAL_CRATE};
 use rustc_hir::definitions::{DefPathData, DefPathDataName, DisambiguatedDefPathData};
+use rustc_hir::LangItem;
 use rustc_session::config::TrimmedDefPaths;
 use rustc_session::cstore::{ExternCrate, ExternCrateSource};
 use rustc_session::Limit;
@@ -889,7 +890,7 @@ pub trait PrettyPrinter<'tcx>:
                                 // Group the return ty with its def id, if we had one.
                                 entry
                                     .return_ty
-                                    .map(|ty| (tcx.lang_items().fn_once_output().unwrap(), ty)),
+                                    .map(|ty| (tcx.require_lang_item(LangItem::FnOnce, None), ty)),
                             );
                         }
                         if let Some(trait_ref) = entry.fn_mut_trait_ref {

compiler/rustc_middle/src/ty/sty.rs

@@ -17,6 +17,7 @@ use rustc_data_structures::captures::Captures;
 use rustc_data_structures::intern::Interned;
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
+use rustc_hir::LangItem;
 use rustc_index::vec::Idx;
 use rustc_macros::HashStable;
 use rustc_span::symbol::{kw, sym, Symbol};
@@ -2108,7 +2109,7 @@ impl<'tcx> Ty<'tcx> {
 
             ty::Str | ty::Slice(_) => (tcx.types.usize, false),
             ty::Dynamic(..) => {
-                let dyn_metadata = tcx.lang_items().dyn_metadata().unwrap();
+                let dyn_metadata = tcx.require_lang_item(LangItem::DynMetadata, None);
                 (tcx.bound_type_of(dyn_metadata).subst(tcx, &[tail.into()]), false)
             },
 

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -2625,7 +2625,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     }
                 };
 
-                let from_generator = tcx.lang_items().from_generator_fn().unwrap();
+                let from_generator = tcx.require_lang_item(LangItem::FromGenerator, None);
 
                 // Don't print the tuple of capture types
                 'print: {