FIX SIMILARTERM for latest Symbolics.jl version

Author: Alessandro

Project.toml

@@ -73,7 +73,7 @@ Setfield = "0.7, 0.8"
 SpecialFunctions = "0.7, 0.8, 0.9, 0.10, 1.0"
 StaticArrays = "0.10, 0.11, 0.12, 1.0"
 SymbolicUtils = "0.18"
-Symbolics = "3.6.0"
+Symbolics = "4.0.0"
 UnPack = "0.1, 1.0"
 Unitful = "1.1"
 julia = "1.2"

src/systems/systemstructure.jl

@@ -16,9 +16,9 @@ using SparseArrays
 
 quick_cancel_expr(expr) = Rewriters.Postwalk(
     quick_cancel,
-    similarterm=(x, f, args) -> similarterm(
+    similarterm=(x, f, args; kws...) -> similarterm(
         x, f, args, SymbolicUtils.symtype(x);
-        metadata=SymbolicUtils.metadata(x)
+        metadata=SymbolicUtils.metadata(x), kws...
     )
 )(expr)