Remove the lifetime from `DiagnosticArgValue`.

Because it's almost always static.

This makes `impl IntoDiagnosticArg for DiagnosticArgValue` trivial,
which is nice.

There are a few diagnostics constructed in
`compiler/rustc_mir_build/src/check_unsafety.rs` and
`compiler/rustc_mir_transform/src/errors.rs` that now need symbols
converted to `String` with `to_string` instead of `&str` with `as_str`,
but that' no big deal, and worth it for the simplifications elsewhere.

1 files changed, 2 insertions, 2 deletions

diff --git a/compiler/rustc_codegen_ssa/src/errors.rs b/compiler/rustc_codegen_ssa/src/errors.rs
index ef291ead190..06ea5b9e8f4 100644
--- a/compiler/rustc_codegen_ssa/src/errors.rs
+++ b/compiler/rustc_codegen_ssa/src/errors.rs
@@ -147,7 +147,7 @@ impl<'a> CopyPath<'a> {
 struct DebugArgPath<'a>(pub &'a Path);
 
 impl IntoDiagnosticArg for DebugArgPath<'_> {
-    fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue {
         DiagnosticArgValue::Str(Cow::Owned(format!("{:?}", self.0)))
     }
 }
@@ -974,7 +974,7 @@ pub enum ExpectedPointerMutability {
 }
 
 impl IntoDiagnosticArg for ExpectedPointerMutability {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue {
         match self {
             ExpectedPointerMutability::Mut => DiagnosticArgValue::Str(Cow::Borrowed("*mut")),
             ExpectedPointerMutability::Not => DiagnosticArgValue::Str(Cow::Borrowed("*_")),