Add a Parse impl for symbol Value

compiler/rustc_macros/src/symbols.rs

@@ -65,13 +65,19 @@ impl Parse for Symbol {
     fn parse(input: ParseStream<'_>) -> Result<Self> {
         let name = input.parse()?;
         let colon_token: Option<Token![:]> = input.parse()?;
-        let value =
-            if colon_token.is_some() { Value::String(input.parse()?) } else { Value::SameAsName };
+        let value = if colon_token.is_some() { input.parse()? } else { Value::SameAsName };
 
         Ok(Symbol { name, value })
     }
 }
 
+impl Parse for Value {
+    fn parse(input: ParseStream<'_>) -> Result<Self> {
+        let lit: LitStr = input.parse()?;
+        Ok(Value::String(lit))
+    }
+}
+
 struct Input {
     keywords: Punctuated<Keyword, Token![,]>,
     symbols: Punctuated<Symbol, Token![,]>,