1 files changed, 13 insertions, 0 deletions
diff --git a/src/libsyntax/parse/token.rs b/src/libsyntax/parse/token.rs
index 472e4b474d6..73adb5c947c 100644
--- a/src/libsyntax/parse/token.rs
+++ b/src/libsyntax/parse/token.rs
@@ -476,6 +476,19 @@ impl Token {
         false
     }
 
+    /// Would `maybe_whole_expr` in `parser.rs` return `Ok(..)`?
+    /// That is, is this a pre-parsed expression dropped into the token stream
+    /// (which happens while parsing the result of macro expansion)?
+    crate fn is_whole_expr(&self) -> bool {
+        if let Interpolated(ref nt) = self.kind {
+            if let NtExpr(_) | NtLiteral(_) | NtPath(_) | NtIdent(..) | NtBlock(_) = **nt {
+                return true;
+            }
+        }
+
+        false
+    }
+
     /// Returns `true` if the token is either the `mut` or `const` keyword.
     crate fn is_mutability(&self) -> bool {
         self.is_keyword(kw::Mut) ||