Autoderive ExternBlockSuggestion

compiler/rustc_ast_passes/src/errors.rs

@@ -1,6 +1,5 @@
 //! Errors emitted by ast_passes.
 
-use rustc_errors::{fluent, AddToDiagnostic, Applicability, Diagnostic, SubdiagnosticMessage};
 use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_span::{Span, Symbol};
 
@@ -207,28 +206,21 @@ pub struct FnWithoutBody {
     pub extern_block_suggestion: Option<ExternBlockSuggestion>,
 }
 
-pub struct ExternBlockSuggestion {
-    pub start_span: Span,
-    pub end_span: Span,
-    pub abi: Option<Symbol>,
-}
-
-impl AddToDiagnostic for ExternBlockSuggestion {
-    fn add_to_diagnostic_with<F>(self, diag: &mut Diagnostic, _: F)
-    where
-        F: Fn(&mut Diagnostic, SubdiagnosticMessage) -> SubdiagnosticMessage,
-    {
-        let start_suggestion = if let Some(abi) = self.abi {
-            format!("extern \"{}\" {{", abi)
-        } else {
-            "extern {".to_owned()
-        };
-        let end_suggestion = " }".to_owned();
-
-        diag.multipart_suggestion(
-            fluent::extern_block_suggestion,
-            vec![(self.start_span, start_suggestion), (self.end_span, end_suggestion)],
-            Applicability::MaybeIncorrect,
-        );
-    }
+#[derive(Subdiagnostic)]
+pub enum ExternBlockSuggestion {
+    #[multipart_suggestion(ast_passes_extern_block_suggestion, applicability = "maybe-incorrect")]
+    Implicit {
+        #[suggestion_part(code = "extern {{")]
+        start_span: Span,
+        #[suggestion_part(code = " }}")]
+        end_span: Span,
+    },
+    #[multipart_suggestion(ast_passes_extern_block_suggestion, applicability = "maybe-incorrect")]
+    Explicit {
+        #[suggestion_part(code = "extern \"{abi}\" {{")]
+        start_span: Span,
+        #[suggestion_part(code = " }}")]
+        end_span: Span,
+        abi: Symbol,
+    },
 }