Auto merge of #124356 - fmease:fewer-magic-numbers-in-names, r=lcnr

Cleanup: Replace item names referencing GitHub issues or error codes with something more meaningful

**lcnr** in #117164 (review):

> […] while I know that there's precendent to name things `Issue69420`, I really dislike this as it requires looking up the issue to figure out the purpose of such a variant. Actually referring to the underlying issue, e.g. `AliasMayNormToUncovered` or whatever and then linking to the issue in a doc comment feels a lot more desirable to me. We should ideally rename all the functions and enums which currently use issue numbers.

I've grepped through `compiler/` like crazy and think that I've found all instances of this pattern.
However, I haven't renamed `compute_2229_migrations_*`. Should I?

The first commit introduces an abhorrent and super long name for an item because naming is hard but also scary looking / unwelcoming names are good for things related to temporary-ish backcompat hacks. I'll let you discover it by yourself.

Contains a bit of drive-by cleanup and a diag migration bc that was the simplest option.

r? lcnr or compiler

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -632,20 +632,19 @@ impl<'a> AstValidator<'a> {
         }
     }
 
-    fn emit_e0568(&self, span: Span, ident: Span) {
-        self.dcx().emit_err(errors::AutoTraitBounds { span, ident });
-    }
-
     fn deny_super_traits(&self, bounds: &GenericBounds, ident_span: Span) {
         if let [.., last] = &bounds[..] {
             let span = ident_span.shrink_to_hi().to(last.span());
-            self.emit_e0568(span, ident_span);
+            self.dcx().emit_err(errors::AutoTraitBounds { span, ident: ident_span });
         }
     }
 
     fn deny_where_clause(&self, where_clause: &WhereClause, ident_span: Span) {
         if !where_clause.predicates.is_empty() {
-            self.emit_e0568(where_clause.span, ident_span);
+            // FIXME: The current diagnostic is misleading since it only talks about
+            // super trait and lifetime bounds while we should just say “bounds”.
+            self.dcx()
+                .emit_err(errors::AutoTraitBounds { span: where_clause.span, ident: ident_span });
         }
     }
 

compiler/rustc_data_structures/src/lib.rs

@@ -144,9 +144,9 @@ pub fn make_display(f: impl Fn(&mut fmt::Formatter<'_>) -> fmt::Result) -> impl
     Printer { f }
 }
 
-// See comments in compiler/rustc_middle/src/tests.rs
+// See comment in compiler/rustc_middle/src/tests.rs and issue #27438.
 #[doc(hidden)]
-pub fn __noop_fix_for_27438() {}
+pub fn __noop_fix_for_windows_dllimport_issue() {}
 
 #[macro_export]
 macro_rules! external_bitflags_debug {

compiler/rustc_hir_analysis/messages.ftl

@@ -201,6 +201,12 @@ hir_analysis_inherent_ty_outside_relevant = cannot define inherent `impl` for a
     .help = consider moving this inherent impl into the crate defining the type if possible
     .span_help = alternatively add `#[rustc_allow_incoherent_impl]` to the relevant impl items
 
+hir_analysis_invalid_receiver_ty = invalid `self` parameter type: `{$receiver_ty}`
+    .note = type of `self` must be `Self` or a type that dereferences to it
+
+hir_analysis_invalid_receiver_ty_help =
+    consider changing to `self`, `&self`, `&mut self`, `self: Box<Self>`, `self: Rc<Self>`, `self: Arc<Self>`, or `self: Pin<P>` (where P is one of the previous types except `Self`)
+
 hir_analysis_invalid_union_field =
     field must implement `Copy` or be wrapped in `ManuallyDrop<...>` to be used in a union
     .note = union fields must not have drop side-effects, which is currently enforced via either `Copy` or `ManuallyDrop<...>`

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -2,6 +2,7 @@ use crate::autoderef::Autoderef;
 use crate::collect::CollectItemTypesVisitor;
 use crate::constrained_generic_params::{identify_constrained_generic_params, Parameter};
 use crate::errors;
+use crate::fluent_generated as fluent;
 
 use hir::intravisit::Visitor;
 use rustc_ast as ast;
@@ -1636,10 +1637,6 @@ fn check_fn_or_method<'tcx>(
     }
 }
 
-const HELP_FOR_SELF_TYPE: &str = "consider changing to `self`, `&self`, `&mut self`, `self: Box<Self>`, \
-     `self: Rc<Self>`, `self: Arc<Self>`, or `self: Pin<P>` (where P is one \
-     of the previous types except `Self`)";
-
 #[instrument(level = "debug", skip(wfcx))]
 fn check_method_receiver<'tcx>(
     wfcx: &WfCheckingCtxt<'_, 'tcx>,
@@ -1675,7 +1672,7 @@ fn check_method_receiver<'tcx>(
     if tcx.features().arbitrary_self_types {
         if !receiver_is_valid(wfcx, span, receiver_ty, self_ty, true) {
             // Report error; `arbitrary_self_types` was enabled.
-            return Err(e0307(tcx, span, receiver_ty));
+            return Err(tcx.dcx().emit_err(errors::InvalidReceiverTy { span, receiver_ty }));
         }
     } else {
         if !receiver_is_valid(wfcx, span, receiver_ty, self_ty, false) {
@@ -1690,24 +1687,17 @@ fn check_method_receiver<'tcx>(
                          the `arbitrary_self_types` feature",
                     ),
                 )
-                .with_help(HELP_FOR_SELF_TYPE)
+                .with_help(fluent::hir_analysis_invalid_receiver_ty_help)
                 .emit()
             } else {
                 // Report error; would not have worked with `arbitrary_self_types`.
-                e0307(tcx, span, receiver_ty)
+                tcx.dcx().emit_err(errors::InvalidReceiverTy { span, receiver_ty })
             });
         }
     }
     Ok(())
 }
 
-fn e0307(tcx: TyCtxt<'_>, span: Span, receiver_ty: Ty<'_>) -> ErrorGuaranteed {
-    struct_span_code_err!(tcx.dcx(), span, E0307, "invalid `self` parameter type: {receiver_ty}")
-        .with_note("type of `self` must be `Self` or a type that dereferences to it")
-        .with_help(HELP_FOR_SELF_TYPE)
-        .emit()
-}
-
 /// Returns whether `receiver_ty` would be considered a valid receiver type for `self_ty`. If
 /// `arbitrary_self_types` is enabled, `receiver_ty` must transitively deref to `self_ty`, possibly
 /// through a `*const/mut T` raw pointer. If the feature is not enabled, the requirements are more

compiler/rustc_hir_analysis/src/errors.rs

@@ -1666,3 +1666,13 @@ pub struct NonConstRange {
     #[primary_span]
     pub span: Span,
 }
+
+#[derive(Diagnostic)]
+#[diag(hir_analysis_invalid_receiver_ty, code = E0307)]
+#[note]
+#[help(hir_analysis_invalid_receiver_ty_help)]
+pub struct InvalidReceiverTy<'tcx> {
+    #[primary_span]
+    pub span: Span,
+    pub receiver_ty: Ty<'tcx>,
+}

compiler/rustc_hir_typeck/src/pat.rs

@@ -1228,16 +1228,22 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 );
             }
         } else {
-            // Pattern has wrong number of fields.
-            let e =
-                self.e0023(pat.span, res, qpath, subpats, &variant.fields.raw, expected, had_err);
+            let e = self.emit_err_pat_wrong_number_of_fields(
+                pat.span,
+                res,
+                qpath,
+                subpats,
+                &variant.fields.raw,
+                expected,
+                had_err,
+            );
             on_error(e);
             return Ty::new_error(tcx, e);
         }
         pat_ty
     }
 
-    fn e0023(
+    fn emit_err_pat_wrong_number_of_fields(
         &self,
         pat_span: Span,
         res: Res,

compiler/rustc_middle/src/query/mod.rs

@@ -847,8 +847,10 @@ rustc_queries! {
         separate_provide_extern
     }
 
-    query issue33140_self_ty(key: DefId) -> Option<ty::EarlyBinder<ty::Ty<'tcx>>> {
-        desc { |tcx| "computing Self type wrt issue #33140 `{}`", tcx.def_path_str(key) }
+    query self_ty_of_trait_impl_enabling_order_dep_trait_object_hack(
+        key: DefId
+    ) -> Option<ty::EarlyBinder<ty::Ty<'tcx>>> {
+        desc { |tcx| "computing self type wrt issue #33140 `{}`", tcx.def_path_str(key) }
     }
 
     /// Maps a `DefId` of a type to a list of its inherent impls.

compiler/rustc_middle/src/tests.rs

@@ -1,11 +1,9 @@
-// FIXME(#27438): right now the unit tests of rustc_middle don't refer to any actual
-//                functions generated in rustc_data_structures (all
-//                references are through generic functions), but statics are
-//                referenced from time to time. Due to this bug we won't
-//                actually correctly link in the statics unless we also
-//                reference a function, so be sure to reference a dummy
-//                function.
+// FIXME(#27438): Right now, the unit tests of `rustc_middle` don't refer to any actual functions
+//                generated in `rustc_data_structures` (all references are through generic functions),
+//                but statics are referenced from time to time. Due to this Windows `dllimport` bug
+//                we won't actually correctly link in the statics unless we also reference a function,
+//                so be sure to reference a dummy function.
 #[test]
 fn noop() {
-    rustc_data_structures::__noop_fix_for_27438();
+    rustc_data_structures::__noop_fix_for_windows_dllimport_issue();
 }

compiler/rustc_middle/src/ty/mod.rs

@@ -1503,14 +1503,14 @@ pub enum ImplOverlapKind {
         /// Whether or not the impl is permitted due to the trait being a `#[marker]` trait
         marker: bool,
     },
-    /// These impls are allowed to overlap, but that raises
-    /// an issue #33140 future-compatibility warning.
+    /// These impls are allowed to overlap, but that raises an
+    /// issue #33140 future-compatibility warning (tracked in #56484).
     ///
     /// Some background: in Rust 1.0, the trait-object types `Send + Sync` (today's
     /// `dyn Send + Sync`) and `Sync + Send` (now `dyn Sync + Send`) were different.
     ///
-    /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied
-    /// that difference, making what reduces to the following set of impls:
+    /// The widely-used version 0.1.0 of the crate `traitobject` had accidentally relied on
+    /// that difference, doing what reduces to the following set of impls:
     ///
     /// ```compile_fail,(E0119)
     /// trait Trait {}
@@ -1535,7 +1535,7 @@ pub enum ImplOverlapKind {
     /// 4. Neither of the impls can have any where-clauses.
     ///
     /// Once `traitobject` 0.1.0 is no longer an active concern, this hack can be removed.
-    Issue33140,
+    FutureCompatOrderDepTraitObjects,
 }
 
 /// Useful source information about where a desugared associated type for an
@@ -1730,27 +1730,26 @@ impl<'tcx> TyCtxt<'tcx> {
             | (ImplPolarity::Negative, ImplPolarity::Negative) => {}
         };
 
-        let is_marker_overlap = {
-            let is_marker_impl =
-                |trait_ref: TraitRef<'_>| -> bool { self.trait_def(trait_ref.def_id).is_marker };
-            is_marker_impl(trait_ref1) && is_marker_impl(trait_ref2)
-        };
+        let is_marker_impl = |trait_ref: TraitRef<'_>| self.trait_def(trait_ref.def_id).is_marker;
+        let is_marker_overlap = is_marker_impl(trait_ref1) && is_marker_impl(trait_ref2);
 
         if is_marker_overlap {
-            Some(ImplOverlapKind::Permitted { marker: true })
-        } else {
-            if let Some(self_ty1) = self.issue33140_self_ty(def_id1) {
-                if let Some(self_ty2) = self.issue33140_self_ty(def_id2) {
-                    if self_ty1 == self_ty2 {
-                        return Some(ImplOverlapKind::Issue33140);
-                    } else {
-                        debug!("found {self_ty1:?} != {self_ty2:?}");
-                    }
-                }
-            }
+            return Some(ImplOverlapKind::Permitted { marker: true });
+        }
 
-            None
+        if let Some(self_ty1) =
+            self.self_ty_of_trait_impl_enabling_order_dep_trait_object_hack(def_id1)
+            && let Some(self_ty2) =
+                self.self_ty_of_trait_impl_enabling_order_dep_trait_object_hack(def_id2)
+        {
+            if self_ty1 == self_ty2 {
+                return Some(ImplOverlapKind::FutureCompatOrderDepTraitObjects);
+            } else {
+                debug!("found {self_ty1:?} != {self_ty2:?}");
+            }
         }
+
+        None
     }
 
     /// Returns `ty::VariantDef` if `res` refers to a struct,

compiler/rustc_mir_build/src/thir/pattern/check_match.rs

@@ -10,9 +10,7 @@ use rustc_arena::{DroplessArena, TypedArena};
 use rustc_ast::Mutability;
 use rustc_data_structures::fx::FxIndexSet;
 use rustc_data_structures::stack::ensure_sufficient_stack;
-use rustc_errors::{
-    codes::*, struct_span_code_err, Applicability, Diag, ErrorGuaranteed, MultiSpan,
-};
+use rustc_errors::{codes::*, struct_span_code_err, Applicability, ErrorGuaranteed, MultiSpan};
 use rustc_hir::def::*;
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::{self as hir, BindingMode, ByRef, HirId};
@@ -24,7 +22,6 @@ use rustc_middle::ty::{self, AdtDef, Ty, TyCtxt};
 use rustc_session::lint::builtin::{
     BINDINGS_WITH_VARIANT_NAME, IRREFUTABLE_LET_PATTERNS, UNREACHABLE_PATTERNS,
 };
-use rustc_session::Session;
 use rustc_span::hygiene::DesugaringKind;
 use rustc_span::{sym, Span};
 
@@ -64,10 +61,6 @@ pub(crate) fn check_match(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Result<(), Err
     visitor.error
 }
 
-fn create_e0004(sess: &Session, sp: Span, error_message: String) -> Diag<'_> {
-    struct_span_code_err!(sess.dcx(), sp, E0004, "{}", &error_message)
-}
-
 #[derive(Debug, Copy, Clone, PartialEq)]
 enum RefutableFlag {
     Irrefutable,
@@ -975,10 +968,11 @@ fn report_non_exhaustive_match<'p, 'tcx>(
 
     // FIXME: migration of this diagnostic will require list support
     let joined_patterns = joined_uncovered_patterns(cx, &witnesses);
-    let mut err = create_e0004(
-        cx.tcx.sess,
+    let mut err = struct_span_code_err!(
+        cx.tcx.dcx(),
         sp,
-        format!("non-exhaustive patterns: {joined_patterns} not covered"),
+        E0004,
+        "non-exhaustive patterns: {joined_patterns} not covered"
     );
     err.span_label(
         sp,

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

@@ -2001,7 +2001,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
                     // any associated items and there are no where-clauses.
                     //
                     // We can just arbitrarily drop one of the impls.
-                    Some(ty::ImplOverlapKind::Issue33140) => {
+                    Some(ty::ImplOverlapKind::FutureCompatOrderDepTraitObjects) => {
                         assert_eq!(other.evaluation, victim.evaluation);
                         DropVictim::Yes
                     }

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

@@ -453,7 +453,7 @@ fn report_conflicting_impls<'tcx>(
             overlap.trait_ref.print_trait_sugared(),
             overlap.self_ty.map_or_else(String::new, |ty| format!(" for type `{ty}`")),
             match used_to_be_allowed {
-                Some(FutureCompatOverlapErrorKind::Issue33140) => ": (E0119)",
+                Some(FutureCompatOverlapErrorKind::OrderDepTraitObjects) => ": (E0119)",
                 _ => "",
             }
         )
@@ -480,7 +480,7 @@ fn report_conflicting_impls<'tcx>(
         }
         Some(kind) => {
             let lint = match kind {
-                FutureCompatOverlapErrorKind::Issue33140 => ORDER_DEPENDENT_TRAIT_OBJECTS,
+                FutureCompatOverlapErrorKind::OrderDepTraitObjects => ORDER_DEPENDENT_TRAIT_OBJECTS,
                 FutureCompatOverlapErrorKind::LeakCheck => COHERENCE_LEAK_CHECK,
             };
             tcx.node_span_lint(

compiler/rustc_trait_selection/src/traits/specialize/specialization_graph.rs

@@ -11,7 +11,7 @@ pub use rustc_middle::traits::specialization_graph::*;
 
 #[derive(Copy, Clone, Debug)]
 pub enum FutureCompatOverlapErrorKind {
-    Issue33140,
+    OrderDepTraitObjects,
     LeakCheck,
 }
 
@@ -150,10 +150,10 @@ impl<'tcx> Children {
                 {
                     match overlap_kind {
                         ty::ImplOverlapKind::Permitted { marker: _ } => {}
-                        ty::ImplOverlapKind::Issue33140 => {
+                        ty::ImplOverlapKind::FutureCompatOrderDepTraitObjects => {
                             *last_lint_mut = Some(FutureCompatOverlapError {
                                 error: create_overlap_error(overlap),
-                                kind: FutureCompatOverlapErrorKind::Issue33140,
+                                kind: FutureCompatOverlapErrorKind::OrderDepTraitObjects,
                             });
                         }
                     }