Parse const generics

Co-Authored-By: Gabriel Smith <yodaldevoid@users.noreply.github.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/src/libsyntax/parse/token.rs b/src/libsyntax/parse/token.rs
index 3b1fa5ea01f..dad32072739 100644
--- a/src/libsyntax/parse/token.rs
+++ b/src/libsyntax/parse/token.rs
@@ -279,6 +279,20 @@ impl Token {
         }
     }
 
+    /// Returns `true` if the token can appear at the start of a const param.
+    pub fn can_begin_const_arg(&self) -> bool {
+        match self {
+            OpenDelim(Brace) => true,
+            Interpolated(ref nt) => match nt.0 {
+                NtExpr(..) => true,
+                NtBlock(..) => true,
+                NtLiteral(..) => true,
+                _ => false,
+            }
+            _ => self.can_begin_literal_or_bool(),
+        }
+    }
+
     /// Returns `true` if the token can appear at the start of a generic bound.
     crate fn can_begin_bound(&self) -> bool {
         self.is_path_start() || self.is_lifetime() || self.is_keyword(keywords::For) ||