Remove getDestination, and use Destination property instead.

src/Stateless/DynamicTriggerBehaviour.cs

@@ -17,10 +17,9 @@ public DynamicTriggerBehaviour(TTrigger trigger, Func<object[], TState> destinat
                 TransitionInfo = info ?? throw new ArgumentNullException(nameof(info));
             }
 
-            public override bool ResultsInTransitionFrom(TState source, object[] args, out TState destination)
+            public void GetDestinationState(TState source, object[] args, out TState destination)
             {
                 destination = _destination(args);
-                return true;
             }
         }
     }

src/Stateless/IgnoredTriggerBehaviour.cs

@@ -8,12 +8,6 @@ public IgnoredTriggerBehaviour(TTrigger trigger, TransitionGuard transitionGuard
                 : base(trigger, transitionGuard)
             {
             }
-
-            public override bool ResultsInTransitionFrom(TState source, object[] args, out TState destination)
-            {
-                destination = default(TState);
-                return false;
-            }
         }
     }
 }

src/Stateless/InternalTriggerBehaviour.cs

@@ -14,12 +14,6 @@ protected InternalTriggerBehaviour(TTrigger trigger, TransitionGuard guard) : ba
             public abstract void Execute(Transition transition, object[] args);
             public abstract Task ExecuteAsync(Transition transition, object[] args);
 
-            public override bool ResultsInTransitionFrom(TState source, object[] args, out TState destination)
-            {
-                destination = source;
-                return false;
-            }
-
             public class Sync : InternalTriggerBehaviour
             {
                 public Action<Transition, object[]> InternalAction { get; }

src/Stateless/ReentryTriggerBehaviour.cs

@@ -14,13 +14,6 @@ public ReentryTriggerBehaviour(TTrigger trigger, TState destination, TransitionG
             {
                 _destination = destination;
             }
-
-            public override bool ResultsInTransitionFrom(TState source, object[] args, out TState destination)
-            {
-                destination = _destination;
-                return true;
-            }
         }
-
     }
 }

src/Stateless/StateMachine.Async.cs

@@ -219,22 +219,23 @@ async Task InternalFireOneAsync(TTrigger trigger, params object[] args)
                         await HandleReentryTriggerAsync(args, representativeState, transition);
                         break;
                     }
-                case DynamicTriggerBehaviour _ when result.Handler.ResultsInTransitionFrom(source, args, out var destination):
+                case DynamicTriggerBehaviour handler:
                     {
+                        handler.GetDestinationState(source, args, out var destination);
                         // Handle transition, and set new state; reentry is permitted from dynamic trigger behaviours.
                         var transition = new Transition(source, destination, trigger, args);
                         await HandleTransitioningTriggerAsync(args, representativeState, transition);
 
                         break;
                     }
-                case TransitioningTriggerBehaviour _ when result.Handler.ResultsInTransitionFrom(source, args, out var destination):
+                case TransitioningTriggerBehaviour handler:
                     {
                         // If a trigger was found on a superstate that would cause unintended reentry, don't trigger.
-                        if (source.Equals(destination))
+                        if (source.Equals(handler.Destination))
                             break;
 
                         // Handle transition, and set new state
-                        var transition = new Transition(source, destination, trigger, args);
+                        var transition = new Transition(source, handler.Destination, trigger, args);
                         await HandleTransitioningTriggerAsync(args, representativeState, transition);
 
                         break;

src/Stateless/StateMachine.cs

@@ -390,11 +390,13 @@ private void InternalFireQueued(TTrigger trigger, params object[] args)
         /// </summary>
         /// <param name="trigger"></param>
         /// <param name="args"></param>
-        void InternalFireOne(TTrigger trigger, params object[] args)
+        private void InternalFireOne(TTrigger trigger, params object[] args)
         {
             // If this is a trigger with parameters, we must validate the parameter(s)
             if (_triggerConfiguration.TryGetValue(trigger, out TriggerWithParameters configuration))
+            {
                 configuration.ValidateParameters(args);
+            }
 
             var source = State;
             var representativeState = GetRepresentation(source);
@@ -420,22 +422,23 @@ void InternalFireOne(TTrigger trigger, params object[] args)
                         HandleReentryTrigger(args, representativeState, transition);
                         break;
                     }
-                case DynamicTriggerBehaviour _ when result.Handler.ResultsInTransitionFrom(source, args, out var destination):
+                case DynamicTriggerBehaviour handler:
                     {
+                        handler.GetDestinationState(source, args, out var destination);
                         // Handle transition, and set new state; reentry is permitted from dynamic trigger behaviours.
                         var transition = new Transition(source, destination, trigger, args);
                         HandleTransitioningTrigger(args, representativeState, transition);
 
                         break;
                     }
-                case TransitioningTriggerBehaviour _ when result.Handler.ResultsInTransitionFrom(source, args, out var destination):
+                case TransitioningTriggerBehaviour handler:
                     {
                         // If a trigger was found on a superstate that would cause unintended reentry, don't trigger.
-                        if (source.Equals(destination))
+                        if (source.Equals(handler.Destination))
                             break;
 
                         // Handle transition, and set new state
-                        var transition = new Transition(source, destination, trigger, args);
+                        var transition = new Transition(source, handler.Destination, trigger, args);
                         HandleTransitioningTrigger(args, representativeState, transition);
 
                         break;

src/Stateless/TransitioningTriggerBehaviour.cs

@@ -12,12 +12,6 @@ public TransitioningTriggerBehaviour(TTrigger trigger, TState destination, Trans
             {
                 Destination = destination;
             }
-
-            public override bool ResultsInTransitionFrom(TState source, object[] args, out TState destination)
-            {
-                destination = Destination;
-                return true;
-            }
         }
     }
 }

src/Stateless/TriggerBehaviour.cs

@@ -37,7 +37,7 @@ protected TriggerBehaviour(TTrigger trigger, TransitionGuard guard)
             internal ICollection<Func<object[], bool>> Guards =>_guard.Guards;
 
             /// <summary>
-            /// GuardConditionsMet is true if all of the guard functions return true
+            /// GuardConditionsMet is true if all the guard functions return true
             /// or if there are no guard functions
             /// </summary>
             public bool GuardConditionsMet(params object[] args) => _guard.GuardConditionsMet(args);
@@ -47,8 +47,6 @@ protected TriggerBehaviour(TTrigger trigger, TransitionGuard guard)
             /// whose guard function returns false
             /// </summary>
             public ICollection<string> UnmetGuardConditions(object[] args) => _guard.UnmetGuardConditions(args);
-
-            public abstract bool ResultsInTransitionFrom(TState source, object[] args, out TState destination);
         }
     }
 }

test/Stateless.Tests/IgnoredTriggerBehaviourFixture.cs

@@ -8,8 +8,12 @@ public class IgnoredTriggerBehaviourFixture
         [Fact]
         public void StateRemainsUnchanged()
         {
-            var ignored = new StateMachine<State, Trigger>.IgnoredTriggerBehaviour(Trigger.X, null);
-            Assert.False(ignored.ResultsInTransitionFrom(State.B, new object[0], out _));
+            var sm = new StateMachine<State, Trigger>(State.A);
+            sm.Configure(State.A).Ignore(Trigger.X);
+
+            sm.Fire(Trigger.X);
+
+            Assert.Equal(State.A, sm.State);
         }
 
         [Fact]
@@ -21,7 +25,7 @@ public void ExposesCorrectUnderlyingTrigger()
             Assert.Equal(Trigger.X, ignored.Trigger);
         }
 
-        protected bool False(params object[] args)
+        private bool False(params object[] args)
         {
             return false;
         }
@@ -35,7 +39,7 @@ public void WhenGuardConditionFalse_IsGuardConditionMetIsFalse()
             Assert.False(ignored.GuardConditionsMet());
         }
 
-        protected bool True(params object[] args)
+        private bool True(params object[] args)
         {
             return true;
         }
@@ -48,6 +52,7 @@ public void WhenGuardConditionTrue_IsGuardConditionMetIsTrue()
 
             Assert.True(ignored.GuardConditionsMet());
         }
+
         [Fact]
         public void IgnoredTriggerMustBeIgnoredSync()
         {

test/Stateless.Tests/SynchronizationContextFixture.cs

@@ -1,4 +1,3 @@
-using System;
 using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
@@ -90,7 +89,7 @@ public async Task Activation_of_state_with_superstate_should_retain_SyncContext(
         sm.Configure(State.A)
             .OnActivateAsync(CaptureThenLoseSyncContext)
             .SubstateOf(State.B);
-            ;
+
         sm.Configure(State.B)
             .OnActivateAsync(CaptureThenLoseSyncContext);
 
@@ -110,7 +109,7 @@ public async Task Deactivation_of_state_with_superstate_should_retain_SyncContex
         sm.Configure(State.A)
             .OnDeactivateAsync(CaptureThenLoseSyncContext)
             .SubstateOf(State.B);
-            ;
+
         sm.Configure(State.B)
             .OnDeactivateAsync(CaptureThenLoseSyncContext);
 

test/Stateless.Tests/TransitioningTriggerBehaviourFixture.cs

@@ -8,8 +8,7 @@ public class TransitioningTriggerBehaviourFixture
         public void TransitionsToDestinationState()
         {
             var transitioning = new StateMachine<State, Trigger>.TransitioningTriggerBehaviour(Trigger.X, State.C, null);
-            Assert.True(transitioning.ResultsInTransitionFrom(State.B, new object[0], out State destination));
-            Assert.Equal(State.C, destination);
+            Assert.Equal(State.C, transitioning.Destination);
         }
     }
 }