make TypeError impl Copy

compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs

@@ -484,9 +484,7 @@ fn try_extract_error_from_region_constraints<'tcx>(
     };
     nice_error.try_report_from_nll().or_else(|| {
         if let SubregionOrigin::Subtype(trace) = cause {
-            Some(
-                infcx.report_and_explain_type_error(*trace, &TypeError::RegionsPlaceholderMismatch),
-            )
+            Some(infcx.report_and_explain_type_error(*trace, TypeError::RegionsPlaceholderMismatch))
         } else {
             None
         }

compiler/rustc_infer/src/infer/error_reporting/mod.rs

@@ -457,7 +457,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     }
 
     /// Adds a note if the types come from similarly named crates
-    fn check_and_note_conflicting_crates(&self, err: &mut Diagnostic, terr: &TypeError<'tcx>) {
+    fn check_and_note_conflicting_crates(&self, err: &mut Diagnostic, terr: TypeError<'tcx>) {
         use hir::def_id::CrateNum;
         use rustc_hir::definitions::DisambiguatedDefPathData;
         use ty::print::Printer;
@@ -561,7 +561,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 }
             }
         };
-        match *terr {
+        match terr {
             TypeError::Sorts(ref exp_found) => {
                 // if they are both "path types", there's a chance of ambiguity
                 // due to different versions of the same crate
@@ -583,7 +583,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         err: &mut Diagnostic,
         cause: &ObligationCause<'tcx>,
         exp_found: Option<ty::error::ExpectedFound<Ty<'tcx>>>,
-        terr: &TypeError<'tcx>,
+        terr: TypeError<'tcx>,
     ) {
         match *cause.code() {
             ObligationCauseCode::Pattern { origin_expr: true, span: Some(span), root_ty } => {
@@ -1432,7 +1432,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         cause: &ObligationCause<'tcx>,
         secondary_span: Option<(Span, String)>,
         mut values: Option<ValuePairs<'tcx>>,
-        terr: &TypeError<'tcx>,
+        terr: TypeError<'tcx>,
         swap_secondary_and_primary: bool,
         prefer_label: bool,
     ) {
@@ -1713,7 +1713,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             ty::error::TypeError::Sorts(terr)
                 if exp_found.map_or(false, |ef| terr.found == ef.found) =>
             {
-                Some(*terr)
+                Some(terr)
             }
             _ => exp_found,
         };
@@ -2091,7 +2091,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     pub fn report_and_explain_type_error(
         &self,
         trace: TypeTrace<'tcx>,
-        terr: &TypeError<'tcx>,
+        terr: TypeError<'tcx>,
     ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
         use crate::traits::ObligationCauseCode::MatchExpressionArm;
 
@@ -2781,12 +2781,12 @@ pub enum FailureCode {
 }
 
 pub trait ObligationCauseExt<'tcx> {
-    fn as_failure_code(&self, terr: &TypeError<'tcx>) -> FailureCode;
+    fn as_failure_code(&self, terr: TypeError<'tcx>) -> FailureCode;
     fn as_requirement_str(&self) -> &'static str;
 }
 
 impl<'tcx> ObligationCauseExt<'tcx> for ObligationCause<'tcx> {
-    fn as_failure_code(&self, terr: &TypeError<'tcx>) -> FailureCode {
+    fn as_failure_code(&self, terr: TypeError<'tcx>) -> FailureCode {
         use self::FailureCode::*;
         use crate::traits::ObligationCauseCode::*;
         match self.code() {
@@ -2823,7 +2823,7 @@ impl<'tcx> ObligationCauseExt<'tcx> for ObligationCause<'tcx> {
                 TypeError::IntrinsicCast => {
                     Error0308("cannot coerce intrinsics to function pointers")
                 }
-                TypeError::ObjectUnsafeCoercion(did) => Error0038(*did),
+                TypeError::ObjectUnsafeCoercion(did) => Error0038(did),
                 _ => Error0308("mismatched types"),
             },
         }

compiler/rustc_infer/src/infer/error_reporting/note.rs

@@ -107,7 +107,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         match origin {
             infer::Subtype(box trace) => {
                 let terr = TypeError::RegionsDoesNotOutlive(sup, sub);
-                let mut err = self.report_and_explain_type_error(trace, &terr);
+                let mut err = self.report_and_explain_type_error(trace, terr);
                 match (*sub, *sup) {
                     (ty::RePlaceholder(_), ty::RePlaceholder(_)) => {}
                     (ty::RePlaceholder(_), _) => {
@@ -406,7 +406,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             }
             infer::Subtype(box trace) => {
                 let terr = TypeError::RegionsPlaceholderMismatch;
-                return self.report_and_explain_type_error(trace, &terr);
+                return self.report_and_explain_type_error(trace, terr);
             }
             _ => return self.report_concrete_failure(placeholder_origin, sub, sup),
         }

compiler/rustc_infer/src/infer/mod.rs

@@ -1527,8 +1527,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         actual: Ty<'tcx>,
         err: TypeError<'tcx>,
     ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
-        let trace = TypeTrace::types(cause, true, expected, actual);
-        self.report_and_explain_type_error(trace, &err)
+        self.report_and_explain_type_error(TypeTrace::types(cause, true, expected, actual), err)
     }
 
     pub fn report_mismatched_consts(
@@ -1538,8 +1537,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         actual: ty::Const<'tcx>,
         err: TypeError<'tcx>,
     ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
-        let trace = TypeTrace::consts(cause, true, expected, actual);
-        self.report_and_explain_type_error(trace, &err)
+        self.report_and_explain_type_error(TypeTrace::consts(cause, true, expected, actual), err)
     }
 
     pub fn replace_bound_vars_with_fresh_vars<T>(

compiler/rustc_middle/src/ty/error.rs

@@ -30,7 +30,8 @@ impl<T> ExpectedFound<T> {
 }
 
 // Data structures used in type unification
-#[derive(Clone, Debug, TypeFoldable, TypeVisitable)]
+#[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable)]
+#[rustc_pass_by_value]
 pub enum TypeError<'tcx> {
     Mismatch,
     ConstnessMismatch(ExpectedFound<ty::BoundConstness>),
@@ -211,7 +212,7 @@ impl<'tcx> fmt::Display for TypeError<'tcx> {
 }
 
 impl<'tcx> TypeError<'tcx> {
-    pub fn must_include_note(&self) -> bool {
+    pub fn must_include_note(self) -> bool {
         use self::TypeError::*;
         match self {
             CyclicTy(_) | CyclicConst(_) | UnsafetyMismatch(_) | ConstnessMismatch(_)
@@ -347,7 +348,7 @@ impl<'tcx> TyCtxt<'tcx> {
     pub fn note_and_explain_type_err(
         self,
         diag: &mut Diagnostic,
-        err: &TypeError<'tcx>,
+        err: TypeError<'tcx>,
         cause: &ObligationCause<'tcx>,
         sp: Span,
         body_owner_def_id: DefId,
@@ -568,7 +569,7 @@ impl<T> Trait<T> for X {
             }
             TargetFeatureCast(def_id) => {
                 let target_spans =
-                    self.get_attrs(*def_id, sym::target_feature).map(|attr| attr.span);
+                    self.get_attrs(def_id, sym::target_feature).map(|attr| attr.span);
                 diag.note(
                     "functions with `#[target_feature]` can only be coerced to `unsafe` function pointers"
                 );
@@ -640,7 +641,7 @@ impl<T> Trait<T> for X {
         self,
         diag: &mut Diagnostic,
         proj_ty: &ty::ProjectionTy<'tcx>,
-        values: &ExpectedFound<Ty<'tcx>>,
+        values: ExpectedFound<Ty<'tcx>>,
         body_owner_def_id: DefId,
         cause_code: &ObligationCauseCode<'_>,
     ) {

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

@@ -1507,8 +1507,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
         }
 
         self.probe(|_| {
-            let err_buf;
-            let mut err = &error.err;
+            let mut err = error.err;
             let mut values = None;
 
             // try to find the mismatched types to report the error with.
@@ -1544,14 +1543,13 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
                         | ObligationCauseCode::ObjectCastObligation(..)
                         | ObligationCauseCode::OpaqueType
                 );
-                if let Err(error) = self.at(&obligation.cause, obligation.param_env).eq_exp(
+                if let Err(new_err) = self.at(&obligation.cause, obligation.param_env).eq_exp(
                     is_normalized_ty_expected,
                     normalized_ty,
                     data.term,
                 ) {
                     values = Some((data, is_normalized_ty_expected, normalized_ty, data.term));
-                    err_buf = error;
-                    err = &err_buf;
+                    err = new_err;
                 }
             }
 

compiler/rustc_typeck/src/check/compare_method.rs

@@ -291,7 +291,7 @@ fn compare_predicate_entailment<'tcx>(
             debug!("sub_types failed: impl ty {:?}, trait ty {:?}", impl_fty, trait_fty);
 
             let (impl_err_span, trait_err_span) =
-                extract_spans_for_error_reporting(&infcx, &terr, &cause, impl_m, trait_m);
+                extract_spans_for_error_reporting(&infcx, terr, &cause, impl_m, trait_m);
 
             cause.span = impl_err_span;
 
@@ -381,7 +381,7 @@ fn compare_predicate_entailment<'tcx>(
                     expected: trait_fty.into(),
                     found: impl_fty.into(),
                 })),
-                &terr,
+                terr,
                 false,
                 false,
             );
@@ -468,7 +468,7 @@ fn check_region_bounds_on_impl_item<'tcx>(
 #[instrument(level = "debug", skip(infcx))]
 fn extract_spans_for_error_reporting<'a, 'tcx>(
     infcx: &infer::InferCtxt<'a, 'tcx>,
-    terr: &TypeError<'_>,
+    terr: TypeError<'_>,
     cause: &ObligationCause<'tcx>,
     impl_m: &ty::AssocItem,
     trait_m: &ty::AssocItem,
@@ -488,7 +488,7 @@ fn extract_spans_for_error_reporting<'a, 'tcx>(
             _ => bug!("{:?} is not a TraitItemKind::Fn", trait_m),
         });
 
-    match *terr {
+    match terr {
         TypeError::ArgumentMutability(i) => {
             (impl_args.nth(i).unwrap(), trait_args.and_then(|mut args| args.nth(i)))
         }
@@ -1143,7 +1143,7 @@ pub(crate) fn compare_const_impl<'tcx>(
                     expected: trait_ty.into(),
                     found: impl_ty.into(),
                 })),
-                &terr,
+                terr,
                 false,
                 false,
             );

compiler/rustc_typeck/src/check/fn_ctxt/checks.rs

@@ -578,7 +578,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // First, check if we just need to wrap some arguments in a tuple.
         if let Some((mismatch_idx, terr)) =
             compatibility_diagonal.iter().enumerate().find_map(|(i, c)| {
-                if let Compatibility::Incompatible(Some(terr)) = c { Some((i, terr)) } else { None }
+                if let Compatibility::Incompatible(Some(terr)) = c {
+                    Some((i, *terr))
+                } else {
+                    None
+                }
             })
         {
             // Is the first bad expected argument a tuple?
@@ -707,8 +711,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 let (expected_ty, _) = formal_and_expected_inputs[*expected_idx];
                 let cause = &self.misc(provided_span);
                 let trace = TypeTrace::types(cause, true, expected_ty, provided_ty);
-                if !matches!(trace.cause.as_failure_code(e), FailureCode::Error0308(_)) {
-                    self.report_and_explain_type_error(trace, e).emit();
+                if !matches!(trace.cause.as_failure_code(*e), FailureCode::Error0308(_)) {
+                    self.report_and_explain_type_error(trace, *e).emit();
                     return true;
                 }
                 false
@@ -732,7 +736,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             let (provided_ty, provided_arg_span) = provided_arg_tys[*provided_idx];
             let cause = &self.misc(provided_arg_span);
             let trace = TypeTrace::types(cause, true, expected_ty, provided_ty);
-            let mut err = self.report_and_explain_type_error(trace, err);
+            let mut err = self.report_and_explain_type_error(trace, *err);
             self.emit_coerce_suggestions(
                 &mut err,
                 &provided_args[*provided_idx],
@@ -802,7 +806,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 Error::Invalid(provided_idx, expected_idx, compatibility) => {
                     let (formal_ty, expected_ty) = formal_and_expected_inputs[expected_idx];
                     let (provided_ty, provided_span) = provided_arg_tys[provided_idx];
-                    if let Compatibility::Incompatible(error) = &compatibility {
+                    if let Compatibility::Incompatible(error) = compatibility {
                         let cause = &self.misc(provided_span);
                         let trace = TypeTrace::types(cause, true, expected_ty, provided_ty);
                         if let Some(e) = error {