diff --git a/src/comp/syntax/ast_util.rs b/src/comp/syntax/ast_util.rs
index 74c3d6dac49..48bdfc47b68 100644
--- a/src/comp/syntax/ast_util.rs
+++ b/src/comp/syntax/ast_util.rs
@@ -104,7 +104,7 @@ fn binop_to_str(op: binop) -> str {
     }
 }
 
-pred lazy_binop(b: binop) -> bool {
+pure fn lazy_binop(b: binop) -> bool {
     alt b { and. { true } or. { true } _ { false } }
 }
 
diff --git a/src/comp/syntax/parse/token.rs b/src/comp/syntax/parse/token.rs
index cf20e0a328e..7e93444e09b 100644
--- a/src/comp/syntax/parse/token.rs
+++ b/src/comp/syntax/parse/token.rs
@@ -180,7 +180,7 @@ fn to_str(r: lexer::reader, t: token) -> str {
 }
 
 
-pred can_begin_expr(t: token) -> bool {
+pure fn can_begin_expr(t: token) -> bool {
     alt t {
       LPAREN. { true }
       LBRACE. { true }