Auto merge of #98970 - Dylan-DPC:rollup-j0od37w, r=Dylan-DPC

Rollup of 5 pull requests

Successful merges:

 - #98881 (Only compute DefKind through the query.)
 - #98884 (macros: `LintDiagnostic` derive)
 - #98964 (fix typo in function name)
 - #98967 (fix typo in note about multiple inaccessible type aliases)
 - #98968 (assert Scalar sanity)

Failed merges:

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

Author: bors

Cargo.lock

@@ -4009,6 +4009,7 @@ dependencies = [
  "rustc_hir",
  "rustc_index",
  "rustc_infer",
+ "rustc_macros",
  "rustc_middle",
  "rustc_parse_format",
  "rustc_session",

compiler/rustc_const_eval/src/interpret/machine.rs

@@ -145,7 +145,7 @@ pub trait Machine<'mir, 'tcx>: Sized {
     }
 
     /// Whether CheckedBinOp MIR statements should actually check for overflow.
-    fn check_binop_checks_overflow(_ecx: &InterpCx<'mir, 'tcx, Self>) -> bool;
+    fn checked_binop_checks_overflow(_ecx: &InterpCx<'mir, 'tcx, Self>) -> bool;
 
     /// Entry point for obtaining the MIR of anything that should get evaluated.
     /// So not just functions and shims, but also const/static initializers, anonymous
@@ -472,7 +472,7 @@ pub macro compile_time_machine(<$mir: lifetime, $tcx: lifetime>) {
     }
 
     #[inline(always)]
-    fn check_binop_checks_overflow(_ecx: &InterpCx<$mir, $tcx, Self>) -> bool {
+    fn checked_binop_checks_overflow(_ecx: &InterpCx<$mir, $tcx, Self>) -> bool {
         true
     }
 

compiler/rustc_const_eval/src/interpret/operand.rs

@@ -306,9 +306,8 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             s.is_ptr() || (number_may_have_provenance && size == self.pointer_size())
         };
         if let Some(s) = scalar_layout {
-            //FIXME(#96185): let size = s.size(self);
-            //FIXME(#96185): assert_eq!(size, mplace.layout.size, "abi::Scalar size does not match layout size");
-            let size = mplace.layout.size; //FIXME(#96185): remove this line
+            let size = s.size(self);
+            assert_eq!(size, mplace.layout.size, "abi::Scalar size does not match layout size");
             let scalar =
                 alloc.read_scalar(alloc_range(Size::ZERO, size), read_provenance(s, size))?;
             return Ok(Some(ImmTy { imm: scalar.into(), layout: mplace.layout }));

compiler/rustc_const_eval/src/interpret/operator.rs

@@ -33,7 +33,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         // As per https://github.com/rust-lang/rust/pull/98738, we always return `false` in the 2nd
         // component when overflow checking is disabled.
         let overflowed =
-            overflowed && (force_overflow_checks || M::check_binop_checks_overflow(self));
+            overflowed && (force_overflow_checks || M::checked_binop_checks_overflow(self));
         // Write the result to `dest`.
         if let Abi::ScalarPair(..) = dest.layout.abi {
             // We can use the optimized path and avoid `place_field` (which might do

compiler/rustc_const_eval/src/interpret/place.rs

@@ -793,7 +793,7 @@ where
                     )
                 };
                 let size = s.size(&tcx);
-                //FIXME(#96185): assert_eq!(dest.layout.size, size, "abi::Scalar size does not match layout size");
+                assert_eq!(size, dest.layout.size, "abi::Scalar size does not match layout size");
                 alloc.write_scalar(alloc_range(Size::ZERO, size), scalar)
             }
             Immediate::ScalarPair(a_val, b_val) => {

compiler/rustc_errors/src/diagnostic.rs

@@ -1,7 +1,7 @@
 use crate::snippet::Style;
 use crate::{
-    CodeSuggestion, DiagnosticMessage, Level, MultiSpan, SubdiagnosticMessage, Substitution,
-    SubstitutionPart, SuggestionStyle,
+    CodeSuggestion, DiagnosticMessage, EmissionGuarantee, Level, LintDiagnosticBuilder, MultiSpan,
+    SubdiagnosticMessage, Substitution, SubstitutionPart, SuggestionStyle,
 };
 use rustc_data_structures::stable_map::FxHashMap;
 use rustc_error_messages::FluentValue;
@@ -168,6 +168,14 @@ pub trait AddSubdiagnostic {
     fn add_to_diagnostic(self, diag: &mut Diagnostic);
 }
 
+/// Trait implemented by lint types. This should not be implemented manually. Instead, use
+/// `#[derive(LintDiagnostic)]` -- see [rustc_macros::LintDiagnostic].
+#[rustc_diagnostic_item = "DecorateLint"]
+pub trait DecorateLint<'a, G: EmissionGuarantee> {
+    /// Decorate and emit a lint.
+    fn decorate_lint(self, diag: LintDiagnosticBuilder<'a, G>);
+}
+
 #[must_use]
 #[derive(Clone, Debug, Encodable, Decodable)]
 pub struct Diagnostic {

compiler/rustc_errors/src/diagnostic_builder.rs

@@ -589,3 +589,26 @@ macro_rules! struct_span_err {
 macro_rules! error_code {
     ($code:ident) => {{ $crate::DiagnosticId::Error(stringify!($code).to_owned()) }};
 }
+
+/// Wrapper around a `DiagnosticBuilder` for creating lints.
+pub struct LintDiagnosticBuilder<'a, G: EmissionGuarantee>(DiagnosticBuilder<'a, G>);
+
+impl<'a, G: EmissionGuarantee> LintDiagnosticBuilder<'a, G> {
+    /// Return the inner `DiagnosticBuilder`, first setting the primary message to `msg`.
+    pub fn build(mut self, msg: impl Into<DiagnosticMessage>) -> DiagnosticBuilder<'a, G> {
+        self.0.set_primary_message(msg);
+        self.0.set_is_lint();
+        self.0
+    }
+
+    /// Create a `LintDiagnosticBuilder` from some existing `DiagnosticBuilder`.
+    pub fn new(err: DiagnosticBuilder<'a, G>) -> LintDiagnosticBuilder<'a, G> {
+        LintDiagnosticBuilder(err)
+    }
+}
+
+impl<'a> LintDiagnosticBuilder<'a, ErrorGuaranteed> {
+    pub fn forget_guarantee(self) -> LintDiagnosticBuilder<'a, ()> {
+        LintDiagnosticBuilder(self.0.forget_guarantee())
+    }
+}

compiler/rustc_errors/src/lib.rs

@@ -370,10 +370,10 @@ impl fmt::Display for ExplicitBug {
 impl error::Error for ExplicitBug {}
 
 pub use diagnostic::{
-    AddSubdiagnostic, Diagnostic, DiagnosticArg, DiagnosticArgValue, DiagnosticId,
+    AddSubdiagnostic, DecorateLint, Diagnostic, DiagnosticArg, DiagnosticArgValue, DiagnosticId,
     DiagnosticStyledString, IntoDiagnosticArg, SubDiagnostic,
 };
-pub use diagnostic_builder::{DiagnosticBuilder, EmissionGuarantee};
+pub use diagnostic_builder::{DiagnosticBuilder, EmissionGuarantee, LintDiagnosticBuilder};
 use std::backtrace::Backtrace;
 
 /// A handler deals with errors and other compiler output.

compiler/rustc_lint/Cargo.toml

@@ -22,3 +22,4 @@ rustc_trait_selection = { path = "../rustc_trait_selection" }
 rustc_parse_format = { path = "../rustc_parse_format" }
 rustc_infer = { path = "../rustc_infer" }
 rustc_type_ir = { path = "../rustc_type_ir" }
+rustc_macros = { path = "../rustc_macros" }

compiler/rustc_lint/src/builtin.rs

@@ -32,15 +32,16 @@ use rustc_ast_pretty::pprust::{self, expr_to_string};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_errors::{
-    fluent, Applicability, Diagnostic, DiagnosticMessage, DiagnosticStyledString, MultiSpan,
+    fluent, Applicability, Diagnostic, DiagnosticMessage, DiagnosticStyledString,
+    LintDiagnosticBuilder, MultiSpan,
 };
 use rustc_feature::{deprecated_attributes, AttributeGate, BuiltinAttribute, GateIssue, Stability};
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{DefId, LocalDefId, LocalDefIdSet, CRATE_DEF_ID};
 use rustc_hir::{ForeignItemKind, GenericParamKind, HirId, PatKind, PredicateOrigin};
 use rustc_index::vec::Idx;
-use rustc_middle::lint::{in_external_macro, LintDiagnosticBuilder};
+use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::layout::{LayoutError, LayoutOf};
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::subst::GenericArgKind;