diff --git a/pcbnew/router/pns_diff_pair.cpp b/pcbnew/router/pns_diff_pair.cpp
index e4a05e9603..e6e1019aa6 100644
--- a/pcbnew/router/pns_diff_pair.cpp
+++ b/pcbnew/router/pns_diff_pair.cpp
@@ -771,7 +771,7 @@ DP_PRIMITIVE_PAIR DIFF_PAIR::EndingPrimitives()
 }
 
 
-bool commonParallelProjection( SEG n, SEG p, SEG &pClip, SEG& nClip )
+bool commonParallelProjection( SEG p, SEG n, SEG &pClip, SEG& nClip )
 {
     SEG n_proj_p( p.LineProject( n.A ), p.LineProject( n.B ) );
 
diff --git a/pcbnew/router/pns_topology.cpp b/pcbnew/router/pns_topology.cpp
index ea7d16e1cd..0612835276 100644
--- a/pcbnew/router/pns_topology.cpp
+++ b/pcbnew/router/pns_topology.cpp
@@ -282,7 +282,7 @@ const ITEM_SET TOPOLOGY::ConnectedItems( ITEM* aStart, int aKindMask )
 }
 
 
-bool commonParallelProjection( SEG n, SEG p, SEG &pClip, SEG& nClip );
+bool commonParallelProjection( SEG p, SEG n, SEG &pClip, SEG& nClip );
 
 
 bool TOPOLOGY::AssembleDiffPair( ITEM* aStart, DIFF_PAIR& aPair )