De-genericize some IntoDiagnostic impls.

These impls are all needed for just a single `IntoDiagnostic` type, not
a family of them.

Note that `ErrorGuaranteed` is the default type parameter for
`IntoDiagnostic`.

Author: nnethercote

compiler/rustc_builtin_macros/src/errors.rs

@@ -1,5 +1,5 @@
 use rustc_errors::{
-    AddToDiagnostic, DiagnosticBuilder, EmissionGuarantee, Handler, IntoDiagnostic, MultiSpan,
+    AddToDiagnostic, DiagnosticBuilder, ErrorGuaranteed, Handler, IntoDiagnostic, MultiSpan,
     SingleLabelManySpans,
 };
 use rustc_macros::{Diagnostic, Subdiagnostic};
@@ -446,9 +446,9 @@ pub(crate) struct EnvNotDefinedWithUserMessage {
 }
 
 // Hand-written implementation to support custom user messages.
-impl<'a, G: EmissionGuarantee> IntoDiagnostic<'a, G> for EnvNotDefinedWithUserMessage {
+impl<'a> IntoDiagnostic<'a> for EnvNotDefinedWithUserMessage {
     #[track_caller]
-    fn into_diagnostic(self, handler: &'a Handler) -> DiagnosticBuilder<'a, G> {
+    fn into_diagnostic(self, handler: &'a Handler) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
         #[expect(
             rustc::untranslatable_diagnostic,
             reason = "cannot translate user-provided messages"
@@ -801,8 +801,8 @@ pub(crate) struct AsmClobberNoReg {
     pub(crate) clobbers: Vec<Span>,
 }
 
-impl<'a, G: EmissionGuarantee> IntoDiagnostic<'a, G> for AsmClobberNoReg {
-    fn into_diagnostic(self, handler: &'a Handler) -> DiagnosticBuilder<'a, G> {
+impl<'a> IntoDiagnostic<'a> for AsmClobberNoReg {
+    fn into_diagnostic(self, handler: &'a Handler) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
         let mut diag =
             handler.struct_diagnostic(crate::fluent_generated::builtin_macros_asm_clobber_no_reg);
         diag.set_span(self.spans.clone());

compiler/rustc_codegen_llvm/src/errors.rs

@@ -5,7 +5,7 @@ use std::path::Path;
 use crate::fluent_generated as fluent;
 use rustc_data_structures::small_c_str::SmallCStr;
 use rustc_errors::{
-    DiagnosticBuilder, EmissionGuarantee, ErrorGuaranteed, Handler, IntoDiagnostic,
+    DiagnosticBuilder, EmissionGuarantee, ErrorGuaranteed, FatalError, Handler, IntoDiagnostic,
 };
 use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_span::Span;
@@ -101,9 +101,9 @@ pub(crate) struct DynamicLinkingWithLTO;
 
 pub(crate) struct ParseTargetMachineConfig<'a>(pub LlvmError<'a>);
 
-impl<G: EmissionGuarantee> IntoDiagnostic<'_, G> for ParseTargetMachineConfig<'_> {
-    fn into_diagnostic(self, handler: &'_ Handler) -> DiagnosticBuilder<'_, G> {
-        let diag: DiagnosticBuilder<'_, G> = self.0.into_diagnostic(handler);
+impl IntoDiagnostic<'_, FatalError> for ParseTargetMachineConfig<'_> {
+    fn into_diagnostic(self, handler: &'_ Handler) -> DiagnosticBuilder<'_, FatalError> {
+        let diag: DiagnosticBuilder<'_, FatalError> = self.0.into_diagnostic(handler);
         let (message, _) = diag.styled_message().first().expect("`LlvmError` with no message");
         let message = handler.eagerly_translate_to_string(message.clone(), diag.args());
 

compiler/rustc_mir_transform/src/errors.rs

@@ -2,7 +2,7 @@ use std::borrow::Cow;
 
 use rustc_errors::{
     Applicability, DecorateLint, DiagnosticArgValue, DiagnosticBuilder, DiagnosticMessage,
-    EmissionGuarantee, Handler, IntoDiagnostic,
+    EmissionGuarantee, ErrorGuaranteed, Handler, IntoDiagnostic,
 };
 use rustc_macros::{Diagnostic, LintDiagnostic, Subdiagnostic};
 use rustc_middle::mir::{AssertKind, UnsafetyViolationDetails};
@@ -62,9 +62,9 @@ pub(crate) struct RequiresUnsafe {
 // so we need to eagerly translate the label here, which isn't supported by the derive API
 // We could also exhaustively list out the primary messages for all unsafe violations,
 // but this would result in a lot of duplication.
-impl<'sess, G: EmissionGuarantee> IntoDiagnostic<'sess, G> for RequiresUnsafe {
+impl<'sess> IntoDiagnostic<'sess> for RequiresUnsafe {
     #[track_caller]
-    fn into_diagnostic(self, handler: &'sess Handler) -> DiagnosticBuilder<'sess, G> {
+    fn into_diagnostic(self, handler: &'sess Handler) -> DiagnosticBuilder<'sess, ErrorGuaranteed> {
         let mut diag = handler.struct_diagnostic(fluent::mir_transform_requires_unsafe);
         diag.code(rustc_errors::DiagnosticId::Error("E0133".to_string()));
         diag.set_span(self.span);

compiler/rustc_parse/src/errors.rs

@@ -2,7 +2,7 @@ use std::borrow::Cow;
 
 use rustc_ast::token::Token;
 use rustc_ast::{Path, Visibility};
-use rustc_errors::{AddToDiagnostic, Applicability, EmissionGuarantee, IntoDiagnostic};
+use rustc_errors::{AddToDiagnostic, Applicability, ErrorGuaranteed, IntoDiagnostic};
 use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_session::errors::ExprParenthesesNeeded;
 use rustc_span::edition::{Edition, LATEST_STABLE_EDITION};
@@ -1038,12 +1038,12 @@ pub(crate) struct ExpectedIdentifier {
     pub help_cannot_start_number: Option<HelpIdentifierStartsWithNumber>,
 }
 
-impl<'a, G: EmissionGuarantee> IntoDiagnostic<'a, G> for ExpectedIdentifier {
+impl<'a> IntoDiagnostic<'a> for ExpectedIdentifier {
     #[track_caller]
     fn into_diagnostic(
         self,
         handler: &'a rustc_errors::Handler,
-    ) -> rustc_errors::DiagnosticBuilder<'a, G> {
+    ) -> rustc_errors::DiagnosticBuilder<'a, ErrorGuaranteed> {
         let token_descr = TokenDescription::from_token(&self.token);
 
         let mut diag = handler.struct_diagnostic(match token_descr {
@@ -1095,12 +1095,12 @@ pub(crate) struct ExpectedSemi {
     pub sugg: ExpectedSemiSugg,
 }
 
-impl<'a, G: EmissionGuarantee> IntoDiagnostic<'a, G> for ExpectedSemi {
+impl<'a> IntoDiagnostic<'a> for ExpectedSemi {
     #[track_caller]
     fn into_diagnostic(
         self,
         handler: &'a rustc_errors::Handler,
-    ) -> rustc_errors::DiagnosticBuilder<'a, G> {
+    ) -> rustc_errors::DiagnosticBuilder<'a, ErrorGuaranteed> {
         let token_descr = TokenDescription::from_token(&self.token);
 
         let mut diag = handler.struct_diagnostic(match token_descr {

compiler/rustc_session/src/errors.rs

@@ -3,7 +3,7 @@ use std::num::NonZeroU32;
 use crate::parse::ParseSess;
 use rustc_ast::token;
 use rustc_ast::util::literal::LitError;
-use rustc_errors::{error_code, DiagnosticMessage, EmissionGuarantee, IntoDiagnostic, MultiSpan};
+use rustc_errors::{error_code, DiagnosticMessage, ErrorGuaranteed, IntoDiagnostic, MultiSpan};
 use rustc_macros::Diagnostic;
 use rustc_span::{BytePos, Span, Symbol};
 use rustc_target::spec::{SplitDebuginfo, StackProtector, TargetTriple};
@@ -13,12 +13,12 @@ pub struct FeatureGateError {
     pub explain: DiagnosticMessage,
 }
 
-impl<'a, G: EmissionGuarantee> IntoDiagnostic<'a, G> for FeatureGateError {
+impl<'a> IntoDiagnostic<'a> for FeatureGateError {
     #[track_caller]
     fn into_diagnostic(
         self,
         handler: &'a rustc_errors::Handler,
-    ) -> rustc_errors::DiagnosticBuilder<'a, G> {
+    ) -> rustc_errors::DiagnosticBuilder<'a, ErrorGuaranteed> {
         let mut diag = handler.struct_diagnostic(self.explain);
         diag.set_span(self.span);
         diag.code(error_code!(E0658));