lint: port variant size difference diagnostics

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

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

@@ -230,3 +230,6 @@ lint-improper-ctypes-array-reason = passing raw arrays by value is not FFI-safe
 lint-improper-ctypes-array-help = consider passing a pointer to the array
 
 lint-improper-ctypes-only-phantomdata = composed only of `PhantomData`
+
+lint-variant-size-differences =
+    enum variant is more than three times larger ({$largest} bytes) than the next largest

compiler/rustc_errors/src/diagnostic.rs

@@ -49,6 +49,54 @@ impl IntoDiagnosticArg for bool {
     }
 }
 
+impl IntoDiagnosticArg for i8 {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.to_string()))
+    }
+}
+
+impl IntoDiagnosticArg for u8 {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.to_string()))
+    }
+}
+
+impl IntoDiagnosticArg for i16 {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.to_string()))
+    }
+}
+
+impl IntoDiagnosticArg for u16 {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.to_string()))
+    }
+}
+
+impl IntoDiagnosticArg for i32 {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.to_string()))
+    }
+}
+
+impl IntoDiagnosticArg for u32 {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.to_string()))
+    }
+}
+
+impl IntoDiagnosticArg for i64 {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.to_string()))
+    }
+}
+
+impl IntoDiagnosticArg for u64 {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.to_string()))
+    }
+}
+
 impl IntoDiagnosticArg for i128 {
     fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
         DiagnosticArgValue::Str(Cow::Owned(self.to_string()))

compiler/rustc_lint/src/types.rs

@@ -1387,11 +1387,8 @@ impl<'tcx> LateLintPass<'tcx> for VariantSizeDifferences {
                     VARIANT_SIZE_DIFFERENCES,
                     enum_definition.variants[largest_index].span,
                     |lint| {
-                        lint.build(&format!(
+                        lint.build(fluent::lint::variant_size_differences)
-                            "enum variant is more than three times \
+                            .set_arg("largest", largest)
-                                          larger ({} bytes) than the next largest",
-                            largest
-                        ))
                             .emit();
                     },
                 );