Auto merge of #107443 - cjgillot:generator-less-query, r=compiler-errors

[rust.git] / compiler / rustc_mir_transform / src / check_packed_ref.rs

diff --git a/compiler/rustc_mir_transform/src/check_packed_ref.rs b/compiler/rustc_mir_transform/src/check_packed_ref.rs
index 3b7ba3f9a67ac97096d1dd166aff9992babc1aee..3e7571aa7a2e7f303fa0e02cc6fbd1f51f7906ac 100644 (file)
--- a/compiler/rustc_mir_transform/src/check_packed_ref.rs
+++ b/compiler/rustc_mir_transform/src/check_packed_ref.rs
@@ -1,17 +1,11 @@
-use rustc_hir::def_id::LocalDefId;
 use rustc_middle::mir::visit::{PlaceContext, Visitor};
 use rustc_middle::mir::*;
-use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_session::lint::builtin::UNALIGNED_REFERENCES;
 
 use crate::util;
 use crate::MirLint;
 
-pub(crate) fn provide(providers: &mut Providers) {
-    *providers = Providers { unsafe_derive_on_repr_packed, ..*providers };
-}
-
 pub struct CheckPackedRef;
 
 impl<'tcx> MirLint<'tcx> for CheckPackedRef {
@@ -30,26 +24,6 @@ struct PackedRefChecker<'a, 'tcx> {
     source_info: SourceInfo,
 }
 
-fn unsafe_derive_on_repr_packed(tcx: TyCtxt<'_>, def_id: LocalDefId) {
-    let lint_hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
-
-    tcx.struct_span_lint_hir(UNALIGNED_REFERENCES, lint_hir_id, tcx.def_span(def_id), |lint| {
-        // FIXME: when we make this a hard error, this should have its
-        // own error code.
-        let extra = if tcx.generics_of(def_id).own_requires_monomorphization() {
-            "with type or const parameters"
-        } else {
-            "that does not derive `Copy`"
-        };
-        let message = format!(
-            "`{}` can't be derived on this `#[repr(packed)]` struct {}",
-            tcx.item_name(tcx.trait_id_of_impl(def_id.to_def_id()).expect("derived trait name")),
-            extra
-        );
-        lint.build(message).emit();
-    });
-}
-
 impl<'tcx> Visitor<'tcx> for PackedRefChecker<'_, 'tcx> {
     fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
         // Make sure we know where in the MIR we are.
@@ -67,14 +41,13 @@ fn visit_place(&mut self, place: &Place<'tcx>, context: PlaceContext, _location:
         if context.is_borrow() {
             if util::is_disaligned(self.tcx, self.body, self.param_env, *place) {
                 let def_id = self.body.source.instance.def_id();
-                if let Some(impl_def_id) = self
-                    .tcx
-                    .impl_of_method(def_id)
-                    .filter(|&def_id| self.tcx.is_builtin_derive(def_id))
+                if let Some(impl_def_id) = self.tcx.impl_of_method(def_id)
+                    && self.tcx.is_builtin_derive(impl_def_id)
                 {
-                    // If a method is defined in the local crate,
-                    // the impl containing that method should also be.
-                    self.tcx.ensure().unsafe_derive_on_repr_packed(impl_def_id.expect_local());
+                    // If we ever reach here it means that the generated derive
+                    // code is somehow doing an unaligned reference, which it
+                    // shouldn't do.
+                    unreachable!();
                 } else {
                     let source_info = self.source_info;
                     let lint_root = self.body.source_scopes[source_info.scope]
@@ -86,8 +59,9 @@ fn visit_place(&mut self, place: &Place<'tcx>, context: PlaceContext, _location:
                         UNALIGNED_REFERENCES,
                         lint_root,
                         source_info.span,
+                        "reference to packed field is unaligned",
                         |lint| {
-                            lint.build("reference to packed field is unaligned")
+                            lint
                                 .note(
                                     "fields of packed structs are not properly aligned, and creating \
                                     a misaligned reference is undefined behavior (even if that \
@@ -98,7 +72,6 @@ fn visit_place(&mut self, place: &Place<'tcx>, context: PlaceContext, _location:
                                     reference with a raw pointer and use `read_unaligned`/`write_unaligned` \
                                     (loads and stores via `*p` must be properly aligned even when using raw pointers)"
                                 )
-                                .emit();
                         },
                     );
                 }