Preserve runtime numeric switch-case evaluation

src/FastExpressionCompiler/FastExpressionCompiler.cs

@@ -6100,8 +6100,7 @@ private static bool TryEmitSwitch(SwitchExpression expr, ILGenerator il, ref Com
                             var testValExpr = testValues[v];
                             if (testValExpr is not ConstantExpression && testValExpr is not DefaultExpression)
                             {
-                                Debug.Assert(false, $"Not supported non-constant,non-default switch case value expression: `{testValExpr}`");
-                                return false;
+                                goto OrderedDispatch;
                             }
                             var testValueLong = testValExpr is ConstantExpression constExpr ? ConvertValueObjectToLong(constExpr.Value) : 0L;
 
@@ -6351,6 +6350,7 @@ private static bool TryEmitSwitch(SwitchExpression expr, ILGenerator il, ref Com
                     }
                 }
 
+            OrderedDispatch:
                 var switchValueIsNullable = switchValueType.IsNullable();
                 Type switchNullableUnderlyingValueType = null;
                 MethodInfo switchNullableHasValueMethod = null;
@@ -8690,7 +8690,8 @@ public static bool TryFindSwitchBranch(SwitchExpression switchExpr, CompilerFlag
                         var testValues = cases[i].TestValues;
                         for (var j = 0; j < testValues.Count; j++)
                         {
-                            if (testValues[j] is not ConstantExpression testConst || testConst.Value == null) continue;
+                            if (testValues[j] is not ConstantExpression testConst) return false;
+                            if (testConst.Value == null) continue;
                             if (switchValLong == ConvertValueObjectToLong(testConst.Value)) { matchedBody = cases[i].Body; return true; }
                         }
                     }

test/FastExpressionCompiler.TestsRunner.Net472/Program.cs

@@ -34,6 +34,7 @@ static void RunLightExpressionTests(object state)
                 var justLightTestsStopwatch = Stopwatch.StartNew();
 
                 var t = (LightExpression.TestRun)state;
+                t.Run(new LightExpression.UnitTests.RuntimeSwitchCaseRegressionTests());
                 t.Run(new LightExpression.UnitTests.StaticFieldAddressRegressionTests());
                 t.Run(new LightExpression.UnitTests.MultidimensionalGetStorageRegressionTests());
                 t.Run(new LightExpression.UnitTests.AbstractConstructorRegressionTests());
@@ -78,6 +79,7 @@ static void RunLightExpressionTests(object state)
             var fecTestsStopwatch = Stopwatch.StartNew();
 
             var fecTests = new TestRun();
+            fecTests.Run(new RuntimeSwitchCaseRegressionTests());
             fecTests.Run(new StaticFieldAddressRegressionTests());
             fecTests.Run(new MultidimensionalGetStorageRegressionTests());
             fecTests.Run(new AbstractConstructorRegressionTests());

test/FastExpressionCompiler.TestsRunner/Program.cs

@@ -63,6 +63,7 @@ public static void Main(string[] args)
             var ltTask = Task.Run(() =>
             {
                 var ltStopwatch = Stopwatch.StartNew();
+                lt.Run(new LightExpression.UnitTests.RuntimeSwitchCaseRegressionTests());
                 lt.Run(new LightExpression.UnitTests.StaticFieldAddressRegressionTests());
                 lt.Run(new LightExpression.UnitTests.MultidimensionalGetStorageRegressionTests());
                 lt.Run(new LightExpression.UnitTests.AbstractConstructorRegressionTests());
@@ -104,6 +105,7 @@ public static void Main(string[] args)
             });
 
             var stStopwatch = Stopwatch.StartNew();
+            st.Run(new RuntimeSwitchCaseRegressionTests());
             st.Run(new StaticFieldAddressRegressionTests());
             st.Run(new MultidimensionalGetStorageRegressionTests());
             st.Run(new AbstractConstructorRegressionTests());

test/FastExpressionCompiler.UnitTests/RuntimeSwitchCaseRegressionTests.cs

@@ -0,0 +1,32 @@
+using System;
+using S = System.Linq.Expressions.Expression;
+#if LIGHT_EXPRESSION
+namespace FastExpressionCompiler.LightExpression.UnitTests;
+#else
+namespace FastExpressionCompiler.UnitTests;
+#endif
+
+public struct RuntimeSwitchCaseRegressionTests : ITestX
+{
+    public void Run(TestRun t) { Numeric_runtime_case_values_are_supported(t); Constant_input_does_not_skip_runtime_tests(t); }
+    public void Numeric_runtime_case_values_are_supported(TestContext t)
+    {
+        var value = S.Parameter(typeof(int)); var test = S.Parameter(typeof(int));
+        var tree = S.Lambda<Func<int, int, int>>(S.Switch(value, S.Constant(-1), S.SwitchCase(S.Constant(7), S.Add(test, S.Constant(1)))), value, test);
+        var system = tree.Compile(); var fast = tree.FromSysExpression().CompileFast(true);
+        if (!t.IsNotNull(fast)) return;
+        foreach (var x in new[] { int.MinValue, -1, 0, 42, int.MaxValue })
+            foreach (var y in new[] { -1, 0, 41, int.MaxValue }) t.AreEqual(system(x, y), fast(x, y));
+    }
+    public static int Calls;
+    public static int Test() { ++Calls; return 42; }
+    public void Constant_input_does_not_skip_runtime_tests(TestContext t)
+    {
+        var tree = S.Lambda<Func<int>>(S.Switch(S.Constant(42), S.Constant(-1),
+            S.SwitchCase(S.Constant(7), S.Call(typeof(RuntimeSwitchCaseRegressionTests).GetMethod(nameof(Test)))),
+            S.SwitchCase(S.Constant(9), S.Constant(42))));
+        var fast = tree.FromSysExpression().CompileFast(true);
+        if (!t.IsNotNull(fast)) return;
+        Calls = 0; t.AreEqual(7, fast()); t.AreEqual(1, Calls);
+    }
+}