Cleanup unused diagnostic emission methods

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -5,6 +5,7 @@ use rustc_hir::attrs::{
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, LOCAL_CRATE, LocalDefId};
 use rustc_hir::{self as hir, Attribute, find_attr};
+use rustc_macros::Diagnostic;
 use rustc_middle::middle::codegen_fn_attrs::{
     CodegenFnAttrFlags, CodegenFnAttrs, PatchableFunctionEntry, SanitizerFnAttrs,
 };
@@ -385,6 +386,17 @@ fn apply_overrides(tcx: TyCtxt<'_>, did: LocalDefId, codegen_fn_attrs: &mut Code
     }
 }
 
+#[derive(Diagnostic)]
+#[diag("non-default `sanitize` will have no effect after inlining")]
+struct SanitizeOnInline {
+    #[note("inlining requested here")]
+    inline_span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag("the async executor can run blocking code, without realtime sanitizer catching it")]
+struct AsyncBlocking;
+
 fn check_result(
     tcx: TyCtxt<'_>,
     did: LocalDefId,
@@ -425,10 +437,12 @@ fn check_result(
             (interesting_spans.sanitize, interesting_spans.inline)
     {
         let hir_id = tcx.local_def_id_to_hir_id(did);
-        tcx.node_span_lint(lint::builtin::INLINE_NO_SANITIZE, hir_id, sanitize_span, |lint| {
-            lint.primary_message("non-default `sanitize` will have no effect after inlining");
-            lint.span_note(inline_span, "inlining requested here");
-        })
+        tcx.emit_node_span_lint(
+            lint::builtin::INLINE_NO_SANITIZE,
+            hir_id,
+            sanitize_span,
+            SanitizeOnInline { inline_span },
+        )
     }
 
     // warn for nonblocking async functions, blocks and closures.
@@ -445,13 +459,11 @@ fn check_result(
                     != rustc_hir::ClosureKind::Closure))
     {
         let hir_id = tcx.local_def_id_to_hir_id(did);
-        tcx.node_span_lint(
+        tcx.emit_node_span_lint(
             lint::builtin::RTSAN_NONBLOCKING_ASYNC,
             hir_id,
             sanitize_span,
-            |lint| {
-                lint.primary_message(r#"the async executor can run blocking code, without realtime sanitizer catching it"#);
-            }
+            AsyncBlocking,
         );
     }
 

compiler/rustc_errors/src/diagnostic.rs

@@ -106,6 +106,7 @@ impl EmissionGuarantee for rustc_span::fatal_error::FatalError {
 pub trait Diagnostic<'a, G: EmissionGuarantee = ErrorGuaranteed> {
     /// Write out as a diagnostic out of `DiagCtxt`.
     #[must_use]
+    #[track_caller]
     fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, G>;
 }
 

compiler/rustc_hir_analysis/src/check/check.rs

@@ -4,14 +4,15 @@ use std::ops::ControlFlow;
 use rustc_abi::{ExternAbi, FieldIdx, ScalableElt};
 use rustc_data_structures::unord::{UnordMap, UnordSet};
 use rustc_errors::codes::*;
-use rustc_errors::{EmissionGuarantee, MultiSpan};
+use rustc_errors::{Diag, DiagCtxtHandle, Diagnostic, EmissionGuarantee, Level, MultiSpan};
 use rustc_hir as hir;
 use rustc_hir::attrs::ReprAttr::ReprPacked;
 use rustc_hir::def::{CtorKind, DefKind};
 use rustc_hir::{LangItem, Node, find_attr, intravisit};
 use rustc_infer::infer::{RegionVariableOrigin, TyCtxtInferExt};
 use rustc_infer::traits::{Obligation, ObligationCauseCode, WellFormedLoc};
 use rustc_lint_defs::builtin::{REPR_TRANSPARENT_NON_ZST_FIELDS, UNSUPPORTED_CALLING_CONVENTIONS};
+use rustc_macros::Diagnostic;
 use rustc_middle::hir::nested_filter;
 use rustc_middle::middle::resolve_bound_vars::ResolvedArg;
 use rustc_middle::middle::stability::EvalResult;
@@ -53,6 +54,22 @@ fn add_abi_diag_help<T: EmissionGuarantee>(abi: ExternAbi, diag: &mut Diag<'_, T
 }
 
 pub fn check_abi(tcx: TyCtxt<'_>, hir_id: hir::HirId, span: Span, abi: ExternAbi) {
+    struct UnsupportedCallingConventions {
+        abi: ExternAbi,
+    }
+
+    impl<'a> Diagnostic<'a, ()> for UnsupportedCallingConventions {
+        fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
+            let Self { abi } = self;
+            let mut lint = Diag::new(
+                dcx,
+                level,
+                format!("{abi} is not a supported ABI for the current target"),
+            );
+            add_abi_diag_help(abi, &mut lint);
+            lint
+        }
+    }
     // FIXME: This should be checked earlier, e.g. in `rustc_ast_lowering`, as this
     // currently only guards function imports, function definitions, and function pointer types.
     // Functions in trait declarations can still use "deprecated" ABIs without any warning.
@@ -64,12 +81,12 @@ pub fn check_abi(tcx: TyCtxt<'_>, hir_id: hir::HirId, span: Span, abi: ExternAbi
             tcx.dcx().span_delayed_bug(span, format!("{abi} should be rejected in ast_lowering"));
         }
         AbiMapping::Deprecated(..) => {
-            tcx.node_span_lint(UNSUPPORTED_CALLING_CONVENTIONS, hir_id, span, |lint| {
-                lint.primary_message(format!(
-                    "{abi} is not a supported ABI for the current target"
-                ));
-                add_abi_diag_help(abi, lint);
-            });
+            tcx.emit_node_span_lint(
+                UNSUPPORTED_CALLING_CONVENTIONS,
+                hir_id,
+                span,
+                UnsupportedCallingConventions { abi },
+            );
         }
     }
 }
@@ -174,6 +191,11 @@ fn check_union_fields(tcx: TyCtxt<'_>, span: Span, item_def_id: LocalDefId) -> b
 
 /// Check that a `static` is inhabited.
 fn check_static_inhabited(tcx: TyCtxt<'_>, def_id: LocalDefId) {
+    #[derive(Diagnostic)]
+    #[diag("static of uninhabited type")]
+    #[note("uninhabited statics cannot be initialized, and any access would be an immediate error")]
+    struct StaticOfUninhabitedType;
+
     // Make sure statics are inhabited.
     // Other parts of the compiler assume that there are no uninhabited places. In principle it
     // would be enough to check this for `extern` statics, as statics with an initializer will
@@ -204,15 +226,11 @@ fn check_static_inhabited(tcx: TyCtxt<'_>, def_id: LocalDefId) {
         }
     };
     if layout.is_uninhabited() {
-        tcx.node_span_lint(
+        tcx.emit_node_span_lint(
             UNINHABITED_STATIC,
             tcx.local_def_id_to_hir_id(def_id),
             span,
-            |lint| {
-                lint.primary_message("static of uninhabited type");
-                lint
-                .note("uninhabited statics cannot be initialized, and any access would be an immediate error");
-            },
+            StaticOfUninhabitedType,
         );
     }
 }
@@ -1637,6 +1655,39 @@ pub(super) fn check_packed_inner(
 }
 
 pub(super) fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, adt: ty::AdtDef<'tcx>) {
+    struct ZeroSizedFieldReprTransparentIncompatibility<'tcx> {
+        unsuited: UnsuitedInfo<'tcx>,
+    }
+
+    impl<'a, 'tcx> Diagnostic<'a, ()> for ZeroSizedFieldReprTransparentIncompatibility<'tcx> {
+        fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
+            let Self { unsuited } = self;
+            let (title, note) = match unsuited.reason {
+                UnsuitedReason::NonExhaustive => (
+                    "external non-exhaustive types",
+                    "is marked with `#[non_exhaustive]`, so it could become non-zero-sized in the future.",
+                ),
+                UnsuitedReason::PrivateField => (
+                    "external types with private fields",
+                    "contains private fields, so it could become non-zero-sized in the future.",
+                ),
+                UnsuitedReason::ReprC => (
+                    "`repr(C)` types",
+                    "is a `#[repr(C)]` type, so it is not guaranteed to be zero-sized on all targets.",
+                ),
+            };
+            Diag::new(
+                dcx,
+                level,
+                format!("zero-sized fields in `repr(transparent)` cannot contain {title}"),
+            )
+            .with_note(format!(
+                "this field contains `{field_ty}`, which {note}",
+                field_ty = unsuited.ty,
+            ))
+        }
+    }
+
     if !adt.repr().transparent() {
         return;
     }
@@ -1747,29 +1798,11 @@ pub(super) fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, adt: ty::AdtDef<'tcx>)
             // If there are any non-trivial fields, then there can be no non-exhaustive 1-zsts.
             // Otherwise, it's only an issue if there's >1 non-exhaustive 1-zst.
             if non_trivial_count > 0 || prev_unsuited_1zst {
-                tcx.node_span_lint(
+                tcx.emit_node_span_lint(
                     REPR_TRANSPARENT_NON_ZST_FIELDS,
                     tcx.local_def_id_to_hir_id(adt.did().expect_local()),
                     field.span,
-                    |lint| {
-                        let title = match unsuited.reason {
-                            UnsuitedReason::NonExhaustive => "external non-exhaustive types",
-                            UnsuitedReason::PrivateField => "external types with private fields",
-                            UnsuitedReason::ReprC => "`repr(C)` types",
-                        };
-                        lint.primary_message(
-                            format!("zero-sized fields in `repr(transparent)` cannot contain {title}"),
-                        );
-                        let note = match unsuited.reason {
-                            UnsuitedReason::NonExhaustive => "is marked with `#[non_exhaustive]`, so it could become non-zero-sized in the future.",
-                            UnsuitedReason::PrivateField => "contains private fields, so it could become non-zero-sized in the future.",
-                            UnsuitedReason::ReprC => "is a `#[repr(C)]` type, so it is not guaranteed to be zero-sized on all targets.",
-                        };
-                        lint.note(format!(
-                            "this field contains `{field_ty}`, which {note}",
-                            field_ty = unsuited.ty,
-                        ));
-                    },
+                    ZeroSizedFieldReprTransparentIncompatibility { unsuited },
                 );
             } else {
                 prev_unsuited_1zst = true;

compiler/rustc_hir_analysis/src/check/mod.rs

@@ -77,7 +77,7 @@ use std::num::NonZero;
 pub use check::{check_abi, check_custom_abi};
 use rustc_abi::VariantIdx;
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
-use rustc_errors::{Diag, ErrorGuaranteed, pluralize, struct_span_code_err};
+use rustc_errors::{ErrorGuaranteed, pluralize, struct_span_code_err};
 use rustc_hir::LangItem;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::intravisit::Visitor;

compiler/rustc_hir_analysis/src/check_unused.rs

@@ -1,10 +1,28 @@
 use rustc_data_structures::unord::{ExtendUnord, UnordSet};
+use rustc_errors::{Diag, DiagCtxtHandle, Diagnostic, Level};
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::LocalDefId;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::lint;
+use rustc_span::Span;
 use tracing::debug;
 
+struct UnusedImport<'tcx> {
+    tcx: TyCtxt<'tcx>,
+    span: Span,
+}
+
+impl<'a, 'tcx> Diagnostic<'a, ()> for UnusedImport<'tcx> {
+    fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
+        let Self { tcx, span } = self;
+        if let Ok(snippet) = tcx.sess.source_map().span_to_snippet(span) {
+            Diag::new(dcx, level, format!("unused import: `{snippet}`"))
+        } else {
+            Diag::new(dcx, level, "unused import")
+        }
+    }
+}
+
 pub(super) fn check_unused_traits(tcx: TyCtxt<'_>, (): ()) {
     let mut used_trait_imports = UnordSet::<LocalDefId>::default();
 
@@ -31,12 +49,11 @@ pub(super) fn check_unused_traits(tcx: TyCtxt<'_>, (): ()) {
             continue;
         }
         let (path, _) = item.expect_use();
-        tcx.node_span_lint(lint::builtin::UNUSED_IMPORTS, item.hir_id(), path.span, |lint| {
-            if let Ok(snippet) = tcx.sess.source_map().span_to_snippet(path.span) {
-                lint.primary_message(format!("unused import: `{snippet}`"));
-            } else {
-                lint.primary_message("unused import");
-            }
-        });
+        tcx.emit_node_span_lint(
+            lint::builtin::UNUSED_IMPORTS,
+            item.hir_id(),
+            path.span,
+            UnusedImport { tcx, span: path.span },
+        );
     }
 }

compiler/rustc_hir_analysis/src/collect.rs

@@ -22,7 +22,9 @@ use rustc_abi::{ExternAbi, Size};
 use rustc_ast::Recovered;
 use rustc_data_structures::assert_matches;
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
-use rustc_errors::{Applicability, Diag, DiagCtxtHandle, E0228, ErrorGuaranteed, StashKey};
+use rustc_errors::{
+    Applicability, Diag, DiagCtxtHandle, Diagnostic, E0228, ErrorGuaranteed, Level, StashKey,
+};
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::intravisit::{self, InferKind, Visitor, VisitorExt};
@@ -610,6 +612,19 @@ pub(super) fn lower_variant_ctor(tcx: TyCtxt<'_>, def_id: LocalDefId) {
 }
 
 pub(super) fn lower_enum_variant_types(tcx: TyCtxt<'_>, def_id: LocalDefId) {
+    struct ReprCIssue {
+        msg: &'static str,
+    }
+
+    impl<'a> Diagnostic<'a, ()> for ReprCIssue {
+        fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
+            let Self { msg } = self;
+            Diag::new(dcx, level, msg)
+                .with_note("`repr(C)` enums with big discriminants are non-portable, and their size in Rust might not match their size in C")
+                .with_help("use `repr($int_ty)` instead to explicitly set the size of this enum")
+        }
+    }
+
     let def = tcx.adt_def(def_id);
     let repr_type = def.repr().discr_type();
     let initial = repr_type.initial_discriminant(tcx);
@@ -659,15 +674,11 @@ pub(super) fn lower_enum_variant_types(tcx: TyCtxt<'_>, def_id: LocalDefId) {
                 } else {
                     "`repr(C)` enum discriminant does not fit into C `int`, and a previous discriminant does not fit into C `unsigned int`"
                 };
-                tcx.node_span_lint(
+                tcx.emit_node_span_lint(
                     rustc_session::lint::builtin::REPR_C_ENUMS_LARGER_THAN_INT,
                     tcx.local_def_id_to_hir_id(def_id),
                     span,
-                    |d| {
-                        d.primary_message(msg)
-                        .note("`repr(C)` enums with big discriminants are non-portable, and their size in Rust might not match their size in C")
-                        .help("use `repr($int_ty)` instead to explicitly set the size of this enum");
-                    }
+                    ReprCIssue { msg },
                 );
             }
         }

compiler/rustc_hir_analysis/src/collect/generics_of.rs

@@ -1,6 +1,7 @@
 use std::ops::ControlFlow;
 
 use rustc_data_structures::assert_matches;
+use rustc_errors::{Diag, DiagCtxtHandle, Diagnostic, Level};
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::intravisit::{self, Visitor, VisitorExt};
@@ -17,6 +18,17 @@ use crate::middle::resolve_bound_vars as rbv;
 pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics {
     use rustc_hir::*;
 
+    struct GenericParametersForbiddenHere {
+        msg: &'static str,
+    }
+
+    impl<'a> Diagnostic<'a, ()> for GenericParametersForbiddenHere {
+        fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
+            let Self { msg } = self;
+            Diag::new(dcx, level, msg)
+        }
+    }
+
     // For an RPITIT, synthesize generics which are equal to the opaque's generics
     // and parent fn's generics compressed into one list.
     if let Some(ty::ImplTraitInTraitData::Trait { fn_def_id, opaque_def_id }) =
@@ -269,13 +281,11 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics {
                     match param_default_policy.expect("no policy for generic param default") {
                         ParamDefaultPolicy::Allowed => {}
                         ParamDefaultPolicy::FutureCompatForbidden => {
-                            tcx.node_span_lint(
+                            tcx.emit_node_span_lint(
                                 lint::builtin::INVALID_TYPE_PARAM_DEFAULT,
                                 param.hir_id,
                                 param.span,
-                                |lint| {
-                                    lint.primary_message(MESSAGE);
-                                },
+                                GenericParametersForbiddenHere { msg: MESSAGE },
                             );
                         }
                         ParamDefaultPolicy::Forbidden => {