diff --git a/compiler/rustc_mir_build/src/check_unsafety.rs b/compiler/rustc_mir_build/src/check_unsafety.rs
index 226df08ff8f..422549755d1 100644
--- a/compiler/rustc_mir_build/src/check_unsafety.rs
+++ b/compiler/rustc_mir_build/src/check_unsafety.rs
@@ -605,7 +605,7 @@ impl UnsafeOpKind {
                 span,
                 UnsafeOpInUnsafeFnCallToUnsafeFunctionRequiresUnsafe {
                     span,
-                    function: &with_no_trimmed_paths!(tcx.def_path_str(*did)),
+                    function: with_no_trimmed_paths!(tcx.def_path_str(*did)),
                     unsafe_not_inherited_note,
                 },
             ),
@@ -696,7 +696,7 @@ impl UnsafeOpKind {
                 span,
                 UnsafeOpInUnsafeFnCallToFunctionWithRequiresUnsafe {
                     span,
-                    function: &with_no_trimmed_paths!(tcx.def_path_str(*function)),
+                    function: with_no_trimmed_paths!(tcx.def_path_str(*function)),
                     missing_target_features: DiagnosticArgValue::StrListSepByAnd(
                         missing.iter().map(|feature| Cow::from(feature.to_string())).collect(),
                     ),
@@ -750,14 +750,14 @@ impl UnsafeOpKind {
                 dcx.emit_err(CallToUnsafeFunctionRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
                     span,
                     unsafe_not_inherited_note,
-                    function: &tcx.def_path_str(*did),
+                    function: tcx.def_path_str(*did),
                 });
             }
             CallToUnsafeFunction(Some(did)) => {
                 dcx.emit_err(CallToUnsafeFunctionRequiresUnsafe {
                     span,
                     unsafe_not_inherited_note,
-                    function: &tcx.def_path_str(*did),
+                    function: tcx.def_path_str(*did),
                 });
             }
             CallToUnsafeFunction(None) if unsafe_op_in_unsafe_fn_allowed => {
@@ -875,7 +875,7 @@ impl UnsafeOpKind {
                     ),
                     build_target_features_count: build_enabled.len(),
                     unsafe_not_inherited_note,
-                    function: &tcx.def_path_str(*function),
+                    function: tcx.def_path_str(*function),
                 });
             }
             CallToFunctionWith { function, missing, build_enabled } => {
@@ -894,7 +894,7 @@ impl UnsafeOpKind {
                     ),
                     build_target_features_count: build_enabled.len(),
                     unsafe_not_inherited_note,
-                    function: &tcx.def_path_str(*function),
+                    function: tcx.def_path_str(*function),
                 });
             }
         }
diff --git a/compiler/rustc_mir_build/src/errors.rs b/compiler/rustc_mir_build/src/errors.rs
index 147001cabb0..3c1ba26a503 100644
--- a/compiler/rustc_mir_build/src/errors.rs
+++ b/compiler/rustc_mir_build/src/errors.rs
@@ -23,10 +23,10 @@ pub struct UnconditionalRecursion {
 #[derive(LintDiagnostic)]
 #[diag(mir_build_unsafe_op_in_unsafe_fn_call_to_unsafe_fn_requires_unsafe)]
 #[note]
-pub struct UnsafeOpInUnsafeFnCallToUnsafeFunctionRequiresUnsafe<'a> {
+pub struct UnsafeOpInUnsafeFnCallToUnsafeFunctionRequiresUnsafe {
     #[label]
     pub span: Span,
-    pub function: &'a str,
+    pub function: String,
     #[subdiagnostic]
     pub unsafe_not_inherited_note: Option<UnsafeNotInheritedLintNote>,
 }
@@ -123,10 +123,10 @@ pub struct UnsafeOpInUnsafeFnBorrowOfLayoutConstrainedFieldRequiresUnsafe {
 #[derive(LintDiagnostic)]
 #[diag(mir_build_unsafe_op_in_unsafe_fn_call_to_fn_with_requires_unsafe)]
 #[help]
-pub struct UnsafeOpInUnsafeFnCallToFunctionWithRequiresUnsafe<'a> {
+pub struct UnsafeOpInUnsafeFnCallToFunctionWithRequiresUnsafe {
     #[label]
     pub span: Span,
-    pub function: &'a str,
+    pub function: String,
     pub missing_target_features: DiagnosticArgValue,
     pub missing_target_features_count: usize,
     #[note]
@@ -140,11 +140,11 @@ pub struct UnsafeOpInUnsafeFnCallToFunctionWithRequiresUnsafe<'a> {
 #[derive(Diagnostic)]
 #[diag(mir_build_call_to_unsafe_fn_requires_unsafe, code = E0133)]
 #[note]
-pub struct CallToUnsafeFunctionRequiresUnsafe<'a> {
+pub struct CallToUnsafeFunctionRequiresUnsafe {
     #[primary_span]
     #[label]
     pub span: Span,
-    pub function: &'a str,
+    pub function: String,
     #[subdiagnostic]
     pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
@@ -163,11 +163,11 @@ pub struct CallToUnsafeFunctionRequiresUnsafeNameless {
 #[derive(Diagnostic)]
 #[diag(mir_build_call_to_unsafe_fn_requires_unsafe_unsafe_op_in_unsafe_fn_allowed, code = E0133)]
 #[note]
-pub struct CallToUnsafeFunctionRequiresUnsafeUnsafeOpInUnsafeFnAllowed<'a> {
+pub struct CallToUnsafeFunctionRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
     #[primary_span]
     #[label]
     pub span: Span,
-    pub function: &'a str,
+    pub function: String,
     #[subdiagnostic]
     pub unsafe_not_inherited_note: Option<UnsafeNotInheritedNote>,
 }
@@ -374,11 +374,11 @@ pub struct BorrowOfLayoutConstrainedFieldRequiresUnsafeUnsafeOpInUnsafeFnAllowed
 #[derive(Diagnostic)]
 #[diag(mir_build_call_to_fn_with_requires_unsafe, code = E0133)]
 #[help]
-pub struct CallToFunctionWithRequiresUnsafe<'a> {
+pub struct CallToFunctionWithRequiresUnsafe {
     #[primary_span]
     #[label]
     pub span: Span,
-    pub function: &'a str,
+    pub function: String,
     pub missing_target_features: DiagnosticArgValue,
     pub missing_target_features_count: usize,
     #[note]
@@ -392,11 +392,11 @@ pub struct CallToFunctionWithRequiresUnsafe<'a> {
 #[derive(Diagnostic)]
 #[diag(mir_build_call_to_fn_with_requires_unsafe_unsafe_op_in_unsafe_fn_allowed, code = E0133)]
 #[help]
-pub struct CallToFunctionWithRequiresUnsafeUnsafeOpInUnsafeFnAllowed<'a> {
+pub struct CallToFunctionWithRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
     #[primary_span]
     #[label]
     pub span: Span,
-    pub function: &'a str,
+    pub function: String,
     pub missing_target_features: DiagnosticArgValue,
     pub missing_target_features_count: usize,
     #[note]