lint: port CString ptr diagnostics

Signed-off-by: David Wood <[email protected]>

Author: davidtwco

compiler/rustc_error_messages/locales/en-US/lint.ftl

@@ -54,3 +54,9 @@ lint-diag-out-of-impl =
     diagnostics should only be created in `SessionDiagnostic`/`AddSubdiagnostic` impls
 
 lint-untranslatable-diag = diagnostics should be created using translatable messages
+
+lint-cstring-ptr = getting the inner pointer of a temporary `CString`
+    .as-ptr-label = this pointer will be invalid
+    .unwrap-label = this `CString` is deallocated at the end of the statement, bind it to a variable to extend its lifetime
+    .note = pointers do not have a lifetime; when calling `as_ptr` the `CString` will be deallocated at the end of the statement because nothing is referencing it as far as the type system is concerned
+    .help = for more information, see https://doc.rust-lang.org/reference/destructors.html

compiler/rustc_lint/src/methods.rs

@@ -1,6 +1,7 @@
 use crate::LateContext;
 use crate::LateLintPass;
 use crate::LintContext;
+use rustc_errors::fluent;
 use rustc_hir::{Expr, ExprKind, PathSegment};
 use rustc_middle::ty;
 use rustc_span::{symbol::sym, ExpnKind, Span};
@@ -88,16 +89,12 @@ fn lint_cstring_as_ptr(
             if let ty::Adt(adt, _) = substs.type_at(0).kind() {
                 if cx.tcx.is_diagnostic_item(sym::cstring_type, adt.did()) {
                     cx.struct_span_lint(TEMPORARY_CSTRING_AS_PTR, as_ptr_span, |diag| {
-                        let mut diag = diag
-                            .build("getting the inner pointer of a temporary `CString`");
-                        diag.span_label(as_ptr_span, "this pointer will be invalid");
-                        diag.span_label(
-                            unwrap.span,
-                            "this `CString` is deallocated at the end of the statement, bind it to a variable to extend its lifetime",
-                        );
-                        diag.note("pointers do not have a lifetime; when calling `as_ptr` the `CString` will be deallocated at the end of the statement because nothing is referencing it as far as the type system is concerned");
-                        diag.help("for more information, see https://doc.rust-lang.org/reference/destructors.html");
-                        diag.emit();
+                        diag.build(fluent::lint::cstring_ptr)
+                            .span_label(as_ptr_span, fluent::lint::as_ptr_label)
+                            .span_label(unwrap.span, fluent::lint::unwrap_label)
+                            .note(fluent::lint::note)
+                            .help(fluent::lint::help)
+                            .emit();
                     });
                 }
             }