= do { let CoPat co pat _ = firstPat eqn1
; var' <- newUniqueId var (hsPatType pat)
; match_result <- match (var':vars) ty (map decomposeFirst_Coercion eqns)
= do { let CoPat co pat _ = firstPat eqn1
; var' <- newUniqueId var (hsPatType pat)
; match_result <- match (var':vars) ty (map decomposeFirst_Coercion eqns)