X-Git-Url: https://gerrit.simantics.org/r/gitweb?p=simantics%2Fplatform.git;a=blobdiff_plain;f=bundles%2Forg.simantics.scl.runtime%2Fscl%2FPrelude.scl;h=84f8b91b6ef97751ea1f0a00b053ece6e2e8be63;hp=b29b04a2fe42025c1538637f10080c921e4bf12f;hb=0fef79ab46ef07e8f7af6ff211c2b884fc4b735d;hpb=2e00706ab0e92835dde7044c43ae569bdce8a074

diff --git a/bundles/org.simantics.scl.runtime/scl/Prelude.scl b/bundles/org.simantics.scl.runtime/scl/Prelude.scl
index b29b04a2f..84f8b91b6 100644
--- a/bundles/org.simantics.scl.runtime/scl/Prelude.scl
+++ b/bundles/org.simantics.scl.runtime/scl/Prelude.scl
@@ -1266,7 +1266,7 @@ instance MonadZero Maybe where
     mzero = Nothing
 
 instance MonadOr Maybe where
-    morelse (Just a) _ = Just a
+    morelse a@(Just _) _ = a
     morelse _ b = b
 
 "`execJust v f` executes the function `f` with parameter value `x`, if `v=Just x`. If `v=Nothing`, the function does nothing."