Improve inferrence coverage

Author: termi-official

test/regression/inference.jl

@@ -46,12 +46,33 @@ using OrdinaryDiffEqLowOrderRK, OrdinaryDiffEqRosenbrock, OrdinaryDiffEqSDIRK
         end
     end
 
-    # ForwardDiff is not fully inferable
-    autodiff = ADTypes.AutoFiniteDiff()
-    inferred2 = [SDIRK2(; autodiff), TRBDF2(; autodiff), KenCarp4(; autodiff), Rosenbrock23(; autodiff), Rodas4(; autodiff)]
-    for alg in inferred2
-        @inferred init(prob, alg)
-        @inferred init(prob2D, alg)
+    @testset "stiff default" begin
+        # Stiff solvers are not fully inferable for the 2D problem with the default args
+        inferred2 = [SDIRK2(), TRBDF2(), KenCarp4(), Rosenbrock23(), Rodas4()]
+        for alg in inferred2
+            @inferred init(prob, alg)
+            @test_broken @inferred init(prob2D, alg)
+        end
+    end
+
+    @testset "stiff fixed chunksize" begin
+        # When choosing a fixed chunksize it works
+        autodiff = ADTypes.AutoForwardDiff(; chunksize=10)
+        inferred3 = [SDIRK2(; autodiff), TRBDF2(; autodiff), KenCarp4(; autodiff), Rosenbrock23(; autodiff), Rodas4(; autodiff)]
+        for alg in inferred3
+            @inferred init(prob, alg)
+            @inferred init(prob2D, alg)
+        end
+    end
+
+    @testset "stiff finite diff" begin
+        # FiniteDiff works
+        autodiff = ADTypes.AutoFiniteDiff()
+        inferred4 = [SDIRK2(; autodiff), TRBDF2(; autodiff), KenCarp4(; autodiff), Rosenbrock23(; autodiff), Rodas4(; autodiff)]
+        for alg in inferred4
+            @inferred init(prob, alg)
+            @inferred init(prob2D, alg)
+        end
     end
 end