Fix two variants of Node::substitute().

Node::substitute() is overloaded.  One version was properly substituting
operators (e.g. the "f" in f(x) could be substituted).  The others were
ignoring anything in function position.  Fixed.  Thanks to Wei Wang for
pointing this out.

1 files changed, 4 insertions, 2 deletions

diff --git a/src/expr/node.h b/src/expr/node.h
index e7c51f0e2..9ada7879c 100644
--- a/src/expr/node.h
+++ b/src/expr/node.h
@@ -1376,7 +1376,9 @@ NodeTemplate<ref_count>::substitute(Iterator1 nodesBegin,
     NodeBuilder<> nb(getKind());
     if(getMetaKind() == kind::metakind::PARAMETERIZED) {
       // push the operator
-      nb << getOperator();
+      nb << getOperator().substitute(nodesBegin, nodesEnd,
+                                     replacementsBegin, replacementsEnd,
+                                     cache);
     }
     for(const_iterator i = begin(),
           iend = end();
@@ -1427,7 +1429,7 @@ NodeTemplate<ref_count>::substitute(Iterator substitutionsBegin,
     NodeBuilder<> nb(getKind());
     if(getMetaKind() == kind::metakind::PARAMETERIZED) {
       // push the operator
-      nb << getOperator();
+      nb << getOperator().substitute(substitutionsBegin, substitutionsEnd, cache);
     }
     for(const_iterator i = begin(),
           iend = end();