Auto merge of rust-lang#120903 - matthiaskrgr:rollup-tmsuzth, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - rust-lang#119213 (simd intrinsics: add simd_shuffle_generic and other missing intrinsics)
 - rust-lang#120272 (Suppress suggestions in derive macro)
 - rust-lang#120773 (large_assignments: Allow moves into functions)
 - rust-lang#120874 (Take empty `where` bounds into account when suggesting predicates)
 - rust-lang#120882 (interpret/write_discriminant: when encoding niched variant, ensure the stored value matches)
 - rust-lang#120883 (interpret: rename ReadExternStatic → ExternStatic)
 - rust-lang#120890 (Adapt `llvm-has-rust-patches` validation to take `llvm-config` into account.)
 - rust-lang#120895 (don't skip coercions for types with errors)
 - rust-lang#120896 (Print kind of coroutine closure)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

compiler/rustc_const_eval/messages.ftl

@@ -98,6 +98,8 @@ const_eval_error = {$error_kind ->
 const_eval_exact_div_has_remainder =
     exact_div: {$a} cannot be divided by {$b} without remainder
 
+const_eval_extern_static =
+    cannot access extern static ({$did})
 const_eval_fn_ptr_call =
     function pointers need an RFC before allowed to be called in {const_eval_const_context}s
 const_eval_for_loop_into_iter_non_const =
@@ -172,6 +174,10 @@ const_eval_invalid_meta =
     invalid metadata in wide pointer: total size is bigger than largest supported object
 const_eval_invalid_meta_slice =
     invalid metadata in wide pointer: slice is bigger than largest supported object
+
+const_eval_invalid_niched_enum_variant_written =
+    trying to set discriminant of a {$ty} to the niched variant, but the value does not match
+
 const_eval_invalid_str =
     this string is not valid UTF-8: {$err}
 const_eval_invalid_tag =
@@ -298,8 +304,6 @@ const_eval_raw_ptr_to_int =
     .note = at compile-time, pointers do not have an integer value
     .note2 = avoiding this restriction via `transmute`, `union`, or raw pointers leads to compile-time undefined behavior
 
-const_eval_read_extern_static =
-    cannot read from extern static ({$did})
 const_eval_read_pointer_as_int =
     unable to turn pointer into integer
 const_eval_realloc_or_alloc_with_offset =

compiler/rustc_const_eval/src/errors.rs

@@ -497,6 +497,9 @@ impl<'a> ReportErrorExt for UndefinedBehaviorInfo<'a> {
             ScalarSizeMismatch(_) => const_eval_scalar_size_mismatch,
             UninhabitedEnumVariantWritten(_) => const_eval_uninhabited_enum_variant_written,
             UninhabitedEnumVariantRead(_) => const_eval_uninhabited_enum_variant_read,
+            InvalidNichedEnumVariantWritten { .. } => {
+                const_eval_invalid_niched_enum_variant_written
+            }
             AbiMismatchArgument { .. } => const_eval_incompatible_types,
             AbiMismatchReturn { .. } => const_eval_incompatible_return_types,
         }
@@ -585,6 +588,9 @@ impl<'a> ReportErrorExt for UndefinedBehaviorInfo<'a> {
                 builder.arg("target_size", info.target_size);
                 builder.arg("data_size", info.data_size);
             }
+            InvalidNichedEnumVariantWritten { enum_ty } => {
+                builder.arg("ty", enum_ty.to_string());
+            }
             AbiMismatchArgument { caller_ty, callee_ty }
             | AbiMismatchReturn { caller_ty, callee_ty } => {
                 builder.arg("caller_ty", caller_ty.to_string());
@@ -793,7 +799,7 @@ impl ReportErrorExt for UnsupportedOpInfo {
             UnsupportedOpInfo::ReadPartialPointer(_) => const_eval_partial_pointer_copy,
             UnsupportedOpInfo::ReadPointerAsInt(_) => const_eval_read_pointer_as_int,
             UnsupportedOpInfo::ThreadLocalStatic(_) => const_eval_thread_local_static,
-            UnsupportedOpInfo::ReadExternStatic(_) => const_eval_read_extern_static,
+            UnsupportedOpInfo::ExternStatic(_) => const_eval_extern_static,
         }
     }
     fn add_args<G: EmissionGuarantee>(self, _: &DiagCtxt, builder: &mut DiagnosticBuilder<'_, G>) {
@@ -812,7 +818,7 @@ impl ReportErrorExt for UnsupportedOpInfo {
             OverwritePartialPointer(ptr) | ReadPartialPointer(ptr) => {
                 builder.arg("ptr", ptr);
             }
-            ThreadLocalStatic(did) | ReadExternStatic(did) => {
+            ThreadLocalStatic(did) | ExternStatic(did) => {
                 builder.arg("did", format!("{did:?}"));
             }
         }

compiler/rustc_const_eval/src/interpret/discriminant.rs

@@ -85,6 +85,14 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                     // Write result.
                     let niche_dest = self.project_field(dest, tag_field)?;
                     self.write_immediate(*tag_val, &niche_dest)?;
+                } else {
+                    // The untagged variant is implicitly encoded simply by having a value that is
+                    // outside the niche variants. But what if the data stored here does not
+                    // actually encode this variant? That would be bad! So let's double-check...
+                    let actual_variant = self.read_discriminant(&dest.to_op(self)?)?;
+                    if actual_variant != variant_index {
+                        throw_ub!(InvalidNichedEnumVariantWritten { enum_ty: dest.layout().ty });
+                    }
                 }
             }
         }

compiler/rustc_const_eval/src/interpret/memory.rs

@@ -557,7 +557,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 if self.tcx.is_foreign_item(def_id) {
                     // This is unreachable in Miri, but can happen in CTFE where we actually *do* support
                     // referencing arbitrary (declared) extern statics.
-                    throw_unsup!(ReadExternStatic(def_id));
+                    throw_unsup!(ExternStatic(def_id));
                 }
 
                 // We don't give a span -- statics don't need that, they cannot be generic or associated.

compiler/rustc_errors/src/diagnostic.rs

@@ -516,6 +516,17 @@ impl Diagnostic {
 
     /// Helper for pushing to `self.suggestions`, if available (not disable).
     fn push_suggestion(&mut self, suggestion: CodeSuggestion) {
+        for subst in &suggestion.substitutions {
+            for part in &subst.parts {
+                let span = part.span;
+                let call_site = span.ctxt().outer_expn_data().call_site;
+                if span.in_derive_expansion() && span.overlaps_or_adjacent(call_site) {
+                    // Ignore if spans is from derive macro.
+                    return;
+                }
+            }
+        }
+
         if let Ok(suggestions) = &mut self.suggestions {
             suggestions.push(suggestion);
         }

compiler/rustc_hir_typeck/src/coercion.rs

@@ -186,17 +186,6 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
         let b = self.shallow_resolve(b);
         debug!("Coerce.tys({:?} => {:?})", a, b);
 
-        // Just ignore error types.
-        if let Err(guar) = (a, b).error_reported() {
-            // Best-effort try to unify these types -- we're already on the error path,
-            // so this will have the side-effect of making sure we have no ambiguities
-            // due to `[type error]` and `_` not coercing together.
-            let _ = self.commit_if_ok(|_| {
-                self.at(&self.cause, self.param_env).eq(DefineOpaqueTypes::Yes, a, b)
-            });
-            return success(vec![], Ty::new_error(self.fcx.tcx, guar), vec![]);
-        }
-
         // Coercing from `!` to any type is allowed:
         if a.is_never() {
             return success(simple(Adjust::NeverToAny)(b), b, vec![]);

compiler/rustc_middle/src/mir/interpret/error.rs

@@ -356,6 +356,8 @@ pub enum UndefinedBehaviorInfo<'tcx> {
     UninhabitedEnumVariantWritten(VariantIdx),
     /// An uninhabited enum variant is projected.
     UninhabitedEnumVariantRead(VariantIdx),
+    /// Trying to set discriminant to the niched variant, but the value does not match.
+    InvalidNichedEnumVariantWritten { enum_ty: Ty<'tcx> },
     /// ABI-incompatible argument types.
     AbiMismatchArgument { caller_ty: Ty<'tcx>, callee_ty: Ty<'tcx> },
     /// ABI-incompatible return types.
@@ -468,7 +470,7 @@ pub enum UnsupportedOpInfo {
     /// Accessing thread local statics
     ThreadLocalStatic(DefId),
     /// Accessing an unsupported extern static.
-    ReadExternStatic(DefId),
+    ExternStatic(DefId),
 }
 
 /// Error information for when the program exhausted the resources granted to it

compiler/rustc_middle/src/ty/diagnostics.rs

@@ -358,11 +358,17 @@ pub fn suggest_constraining_type_params<'a>(
         //      trait Foo<T=()> {... }
         //                     - insert: `where T: Zar`
         if matches!(param.kind, hir::GenericParamKind::Type { default: Some(_), .. }) {
+            // If we are here and the where clause span is of non-zero length
+            // it means we're dealing with an empty where clause like this:
+            //      fn foo<X>(x: X) where { ... }
+            // In that case we don't want to add another "where" (Fixes #120838)
+            let where_prefix = if generics.where_clause_span.is_empty() { " where" } else { "" };
+
             // Suggest a bound, but there is no existing `where` clause *and* the type param has a
             // default (`<T=Foo>`), so we suggest adding `where T: Bar`.
             suggestions.push((
                 generics.tail_span_for_predicate_suggestion(),
-                format!(" where {param_name}: {constraint}"),
+                format!("{where_prefix} {param_name}: {constraint}"),
                 SuggestChangingConstraintsMessage::RestrictTypeFurther { ty: param_name },
             ));
             continue;

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

@@ -877,7 +877,24 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
             ty::CoroutineClosure(did, args) => {
                 p!(write("{{"));
                 if !self.should_print_verbose() {
-                    p!(write("coroutine-closure"));
+                    match self.tcx().coroutine_kind(self.tcx().coroutine_for_closure(did)).unwrap()
+                    {
+                        hir::CoroutineKind::Desugared(
+                            hir::CoroutineDesugaring::Async,
+                            hir::CoroutineSource::Closure,
+                        ) => p!("async closure"),
+                        hir::CoroutineKind::Desugared(
+                            hir::CoroutineDesugaring::AsyncGen,
+                            hir::CoroutineSource::Closure,
+                        ) => p!("async gen closure"),
+                        hir::CoroutineKind::Desugared(
+                            hir::CoroutineDesugaring::Gen,
+                            hir::CoroutineSource::Closure,
+                        ) => p!("gen closure"),
+                        _ => unreachable!(
+                            "coroutine from coroutine-closure should have CoroutineSource::Closure"
+                        ),
+                    }
                     // FIXME(eddyb) should use `def_span`.
                     if let Some(did) = did.as_local() {
                         if self.tcx().sess.opts.unstable_opts.span_free_formats {

compiler/rustc_monomorphize/src/collector.rs

@@ -666,7 +666,15 @@ impl<'a, 'tcx> MirUsedCollector<'a, 'tcx> {
         debug!(?def_id, ?fn_span);
 
         for arg in args {
-            if let Some(too_large_size) = self.operand_size_if_too_large(limit, &arg.node) {
+            // Moving args into functions is typically implemented with pointer
+            // passing at the llvm-ir level and not by memcpy's. So always allow
+            // moving args into functions.
+            let operand: &mir::Operand<'tcx> = &arg.node;
+            if let mir::Operand::Move(_) = operand {
+                continue;
+            }
+
+            if let Some(too_large_size) = self.operand_size_if_too_large(limit, operand) {
                 self.lint_large_assignment(limit.0, too_large_size, location, arg.span);
             };
         }