Use a "Path" instead of "String" for FromStr's error methods (#410)

Co-authored-by: Peter Glotfelty <peter@glotfelty.us>

Author: Peternator7

strum_macros/src/helpers/metadata.rs

@@ -95,16 +95,12 @@ impl Parse for EnumMeta {
         } else if lookahead.peek(kw::parse_err_ty) {
             let kw = input.parse::<kw::parse_err_ty>()?;
             input.parse::<Token![=]>()?;
-            let path_str: LitStr = input.parse()?;
-            let path_tokens = parse_str(&path_str.value())?;
-            let path = parse2(path_tokens)?;
+            let path: Path = input.parse()?;
             Ok(EnumMeta::ParseErrTy { kw, path })
         } else if lookahead.peek(kw::parse_err_fn) {
             let kw = input.parse::<kw::parse_err_fn>()?;
             input.parse::<Token![=]>()?;
-            let path_str: LitStr = input.parse()?;
-            let path_tokens = parse_str(&path_str.value())?;
-            let path = parse2(path_tokens)?;
+            let path: Path = input.parse()?;
             Ok(EnumMeta::ParseErrFn { kw, path })
         } else if lookahead.peek(kw::const_into_str) {
             Ok(EnumMeta::ConstIntoStr(input.parse()?))

strum_tests/tests/from_str.rs

@@ -232,8 +232,8 @@ fn color_default_with_white() {
 
 #[derive(Debug, EnumString)]
 #[strum(
-    parse_err_fn = "some_enum_not_found_err",
-    parse_err_ty = "CaseCustomParseErrorNotFoundError"
+    parse_err_fn = some_enum_not_found_err,
+    parse_err_ty = CaseCustomParseErrorNotFoundError
 )]
 enum CaseCustomParseErrorEnum {
     #[strum(serialize = "red")]