Move catch_unwind into from_str_checked

Author: dtolnay

src/fallback.rs

@@ -21,6 +21,8 @@ use core::str;
 #[cfg(feature = "proc-macro")]
 use core::str::FromStr;
 use std::ffi::CStr;
+#[cfg(wrap_proc_macro)]
+use std::panic;
 #[cfg(procmacro2_semver_exempt)]
 use std::path::PathBuf;
 
@@ -1224,7 +1226,12 @@ fn escape_utf8(string: &str, repr: &mut String) {
 pub(crate) trait FromStr2: FromStr<Err = proc_macro::LexError> {
     #[cfg(wrap_proc_macro)]
     fn from_str_checked(src: &str) -> Result<Self, imp::LexError> {
-        Self::from_str(src).map_err(imp::LexError::Compiler)
+        // Catch panic to work around https://github.com/rust-lang/rust/issues/58736.
+        match panic::catch_unwind(|| Self::from_str(src)) {
+            Ok(Ok(ok)) => Ok(ok),
+            Ok(Err(lex)) => Err(imp::LexError::Compiler(lex)),
+            Err(_panic) => Err(imp::LexError::CompilerPanic),
+        }
     }
 
     fn from_str_unchecked(src: &str) -> Self {

src/wrapper.rs

@@ -8,7 +8,6 @@ use core::fmt::{self, Debug, Display};
 use core::ops::Range;
 use core::ops::RangeBounds;
 use std::ffi::CStr;
-use std::panic;
 #[cfg(super_unstable)]
 use std::path::PathBuf;
 
@@ -88,12 +87,9 @@ impl TokenStream {
 
     pub(crate) fn from_str_checked(src: &str) -> Result<Self, LexError> {
         if inside_proc_macro() {
-            // Catch panic to work around https://github.com/rust-lang/rust/issues/58736.
-            match panic::catch_unwind(|| proc_macro::TokenStream::from_str_checked(src)) {
-                Ok(Ok(tokens)) => Ok(TokenStream::Compiler(DeferredTokenStream::new(tokens))),
-                Ok(Err(lex)) => Err(lex),
-                Err(_panic) => Err(LexError::CompilerPanic),
-            }
+            Ok(TokenStream::Compiler(DeferredTokenStream::new(
+                proc_macro::TokenStream::from_str_checked(src)?,
+            )))
         } else {
             Ok(TokenStream::Fallback(
                 fallback::TokenStream::from_str_checked(src)?,