fix the true issue

Author: ChrisRackauckas

lib/OrdinaryDiffEqCore/src/caches/basic_caches.jl

@@ -17,9 +17,7 @@ mutable struct CompositeCache{T, F} <: OrdinaryDiffEqCache
 end
 
 function ismutablecache(cache::CompositeCache{T, F}) where {T, F}
-    @show T
-    @show eltype(T)
-    @show eltype(T) <: OrdinaryDiffEqMutableCache
+    eltype(T) <: OrdinaryDiffEqMutableCache
 end
 
 function get_fsalfirstlast(cache::CompositeCache, u)
@@ -54,7 +52,7 @@ function get_fsalfirstlast(cache::DefaultCache, u)
 end
 
 function ismutablecache(cache::DefaultCache{T1, T2, T3, T4, T5, T6, A, F, uType}) where {T1, T2, T3, T4, T5, T6, A, F, uType}
-    T1 isa OrdinaryDiffEqMutableCache
+    T1 <: OrdinaryDiffEqMutableCache
 end
 
 function alg_cache(alg::CompositeAlgorithm, u, rate_prototype, ::Type{uEltypeNoUnits},

lib/OrdinaryDiffEqCore/src/integrators/integrator_utils.jl

@@ -482,8 +482,7 @@ function reset_fsal!(integrator)
     # Ignore DAEs but they already re-ran initialization
     # Mass matrix DAEs do need to reset FSAL if available
     if !(integrator.sol.prob isa DAEProblem)
-        @show integrator.cache
-        if @show ismutablecache(integrator.cache)
+        if ismutablecache(integrator.cache)
             integrator.f(integrator.fsalfirst, integrator.u, integrator.p, integrator.t)
         else
             integrator.fsalfirst = integrator.f(integrator.u, integrator.p, integrator.t)