lint: port path statement diagnostics

Signed-off-by: David Wood <david.wood@huawei.com>

Author: davidtwco

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

@@ -273,3 +273,8 @@ lint-unused-generator =
     .note = generators are lazy and do nothing unless resumed
 
 lint-unused-def = unused {$pre}`{$def}`{$post} that must be used
+
+lint-path-statement-drop = path statement drops value
+    .suggestion = use `drop` to clarify the intent
+
+lint-path-statement-no-effect = path statement with no effect

compiler/rustc_lint/src/unused.rs

@@ -360,20 +360,20 @@ impl<'tcx> LateLintPass<'tcx> for PathStatements {
                 cx.struct_span_lint(PATH_STATEMENTS, s.span, |lint| {
                     let ty = cx.typeck_results().expr_ty(expr);
                     if ty.needs_drop(cx.tcx, cx.param_env) {
-                        let mut lint = lint.build("path statement drops value");
+                        let mut lint = lint.build(fluent::lint::path_statement_drop);
                         if let Ok(snippet) = cx.sess().source_map().span_to_snippet(expr.span) {
                             lint.span_suggestion(
                                 s.span,
-                                "use `drop` to clarify the intent",
+                                fluent::lint::suggestion,
                                 format!("drop({});", snippet),
                                 Applicability::MachineApplicable,
                             );
                         } else {
-                            lint.span_help(s.span, "use `drop` to clarify the intent");
+                            lint.span_help(s.span, fluent::lint::suggestion);
                         }
                         lint.emit();
                     } else {
-                        lint.build("path statement with no effect").emit();
+                        lint.build(fluent::lint::path_statement_no_effect).emit();
                     }
                 });
             }