avoid some `&str` to `String` conversions

2 files changed, 3 insertions, 8 deletions

diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index 0f58206eee9..072a52079e3 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -928,10 +928,7 @@ impl<'a> Resolver<'a> {
                     "generic parameters with a default cannot use \
                                                 forward declared identifiers"
                 );
-                err.span_label(
-                    span,
-                    "defaulted generic parameters cannot be forward declared".to_string(),
-                );
+                err.span_label(span, "defaulted generic parameters cannot be forward declared");
                 err
             }
             ResolutionError::ParamInTyOfConstParam(name) => {
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index 03cb1cfcfc9..677d7036b2f 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -349,10 +349,8 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
 
             err.code(rustc_errors::error_code!(E0424));
             err.span_label(span, match source {
-                PathSource::Pat => "`self` value is a keyword and may not be bound to variables or shadowed"
-                                   .to_string(),
-                _ => "`self` value is a keyword only available in methods with a `self` parameter"
-                     .to_string(),
+                PathSource::Pat => "`self` value is a keyword and may not be bound to variables or shadowed",
+                _ => "`self` value is a keyword only available in methods with a `self` parameter",
             });
             if let Some((fn_kind, span)) = &self.diagnostic_metadata.current_function {
                 // The current function has a `self' parameter, but we were unable to resolve