Give `DiagnosticBuilder` a default type.

`IntoDiagnostic` defaults to `ErrorGuaranteed`, because errors are the
most common diagnostic level. It makes sense to do likewise for the
closely-related (and much more widely used) `DiagnosticBuilder` type,
letting us write `DiagnosticBuilder<'a, ErrorGuaranteed>` as just
`DiagnosticBuilder<'a>`. This cuts over 200 lines of code due to many
multi-line things becoming single line things.

1 files changed, 2 insertions, 7 deletions

diff --git a/compiler/rustc_session/src/errors.rs b/compiler/rustc_session/src/errors.rs
index 8ab31f6f382..9f7d918d98b 100644
--- a/compiler/rustc_session/src/errors.rs
+++ b/compiler/rustc_session/src/errors.rs
@@ -4,8 +4,7 @@ use crate::parse::ParseSess;
 use rustc_ast::token;
 use rustc_ast::util::literal::LitError;
 use rustc_errors::{
-    error_code, DiagCtxt, DiagnosticBuilder, DiagnosticMessage, ErrorGuaranteed, IntoDiagnostic,
-    Level, MultiSpan,
+    error_code, DiagCtxt, DiagnosticBuilder, DiagnosticMessage, IntoDiagnostic, Level, MultiSpan,
 };
 use rustc_macros::Diagnostic;
 use rustc_span::{BytePos, Span, Symbol};
@@ -18,11 +17,7 @@ pub struct FeatureGateError {
 
 impl<'a> IntoDiagnostic<'a> for FeatureGateError {
     #[track_caller]
-    fn into_diagnostic(
-        self,
-        dcx: &'a DiagCtxt,
-        level: Level,
-    ) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
+    fn into_diagnostic(self, dcx: &'a DiagCtxt, level: Level) -> DiagnosticBuilder<'a> {
         let mut diag = DiagnosticBuilder::new(dcx, level, self.explain);
         diag.set_span(self.span);
         diag.code(error_code!(E0658));