errors: impl IntoDiagnosticArg for char

Implements `IntoDiagnosticArg` for `char` using its `Debug`
implementation and introduces a macro for those types which just
delegate the implementation to `ToString`.

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

Author: davidtwco

compiler/rustc_errors/src/diagnostic.rs

@@ -40,6 +40,34 @@ pub trait IntoDiagnosticArg {
     fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static>;
 }
 
+macro_rules! into_diagnostic_arg_using_display {
+    ($( $ty:ty ),+ $(,)?) => {
+        $(
+            impl IntoDiagnosticArg for $ty {
+                fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+                    self.to_string().into_diagnostic_arg()
+                }
+            }
+        )+
+    }
+}
+
+into_diagnostic_arg_using_display!(
+    i8,
+    u8,
+    i16,
+    u16,
+    i32,
+    u32,
+    i64,
+    u64,
+    i128,
+    u128,
+    std::num::NonZeroU32,
+    Edition,
+    Ident,
+);
+
 impl IntoDiagnosticArg for bool {
     fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
         if self {
@@ -50,81 +78,9 @@ 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 {
+impl IntoDiagnosticArg for char {
     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()))
-    }
-}
-
-impl IntoDiagnosticArg for u128 {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Owned(self.to_string()))
-    }
-}
-
-impl IntoDiagnosticArg for String {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Owned(self))
-    }
-}
-
-impl IntoDiagnosticArg for std::num::NonZeroU32 {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Owned(self.to_string()))
-    }
-}
-
-impl IntoDiagnosticArg for Edition {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Owned(self.to_string()))
+        DiagnosticArgValue::Str(Cow::Owned(format!("{:?}", self)))
     }
 }
 
@@ -134,15 +90,15 @@ impl IntoDiagnosticArg for Symbol {
     }
 }
 
-impl IntoDiagnosticArg for Ident {
+impl<'a> IntoDiagnosticArg for &'a str {
     fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
         self.to_string().into_diagnostic_arg()
     }
 }
 
-impl<'a> IntoDiagnosticArg for &'a str {
+impl IntoDiagnosticArg for String {
     fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        self.to_string().into_diagnostic_arg()
+        DiagnosticArgValue::Str(Cow::Owned(self))
     }
 }