some fixes and better DiagInfo aware PrintIL

Author: dadhi

src/FastExpressionCompiler/ILReader.cs

@@ -62,7 +62,13 @@ public static ILReader GetILReaderOrNull(MethodBase source)
         return null;
     }
 
-    public static StringBuilder ToILString(this MethodInfo method, StringBuilder s = null) => ToILString(GetILReaderOrNull(method), s);
+    public static StringBuilder ToILString(this MethodInfo method, StringBuilder s = null)
+    {
+        var il = GetILReaderOrNull(method);
+        return il != null
+            ? il.ToILString(s)
+            : (s ?? new StringBuilder()).AppendLine($"ILReader for {method} is not supported");
+    }
 
     public static StringBuilder ToILString(this IEnumerable<ILInstruction> ilInstructions, StringBuilder s = null)
     {

src/FastExpressionCompiler/TestTools.cs

@@ -134,28 +134,27 @@ public static void PrintCSharp(this Expression expr, ref string result)
         Console.WriteLine(result = expr.ToCSharpString());
     }
 
-    public static void PrintIL(this Delegate @delegate, [CallerMemberName] string tag = null)
+    public static void PrintIL(this Delegate dlg, [CallerMemberName] string tag = null)
     {
         if (!AllowPrintIL) return;
-        @delegate.Method.PrintIL(tag);
+        if (dlg.TryGetDebugInfo() is { } diagInfo)
+            diagInfo.PrintIL(tag);
+        else
+            dlg.Method.PrintIL(tag);
     }
 
-    public static void PrintIL(this MethodInfo method, string tag = null)
-    {
-        if (!AllowPrintIL) return;
-        var s = new StringBuilder();
-        s.Append(tag == null ? "<il>" : "<" + tag + ">").AppendLine();
-        method.ToILString(s);
-        s.AppendLine().Append(tag == null ? "</il>" : "</" + tag + ">");
-        Console.WriteLine(s);
-    }
+    public static void PrintIL(this MethodInfo method, [CallerMemberName] string tag = null) =>
+        PrintIL(tag, method, static (m, s) => m.ToILString(s));
+
+    public static void PrintIL(this IDelegateDebugInfo diagInfo, [CallerMemberName] string tag = null) =>
+        PrintIL(tag, diagInfo, static (di, s) => s.Append(di.ILString));
 
-    public static void PrintIL(this IDelegateDebugInfo delegateDebugInfo, string tag = null)
+    private static void PrintIL<A>(string tag, A state, Action<A, StringBuilder> printIL)
     {
         if (!AllowPrintIL) return;
         var s = new StringBuilder();
         s.Append(tag == null ? "<il>" : "<" + tag + ">").AppendLine();
-        s.Append(delegateDebugInfo.ILString);
+        printIL(state, s);
         s.AppendLine().Append(tag == null ? "</il>" : "</" + tag + ">");
         Console.WriteLine(s);
     }
@@ -475,8 +474,7 @@ public static bool IsInstanceOf<T>(object actual,
     [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:RequiresUnreferencedCode",
         Justification = "The method is used for the testing purposes only.")]
     public static E Throws<E>(Action action,
-        [CallerArgumentExpression(nameof(action))]
-        string actionName = "<action to throw>")
+        [CallerArgumentExpression(nameof(action))] string actionName = "<action to throw>")
         where E : Exception
     {
         try

test/FastExpressionCompiler.IssueTests/Issue316_in_parameter.cs

@@ -60,16 +60,16 @@ public void Test_constructor_in_struct_parameter_constant()
             var position = new TextPosition { Position = 42 };
             var program = Throw(New(typeof(ParseException).GetConstructors()[0], Constant("314"), Constant(position)));
 
-            var expr = Expression.Lambda<Action>(program);
+            var expr = Lambda<Action>(program);
             expr.PrintCSharp(s => s.Replace(GetType().Name + ".", ""));
 
-            var fSys = expr.CompileSys();
-            fSys.PrintIL("sys");
-            Asserts.Throws<ParseException>(() => fSys());
+            var fs = expr.CompileSys();
+            fs.PrintIL("sys");
+            Asserts.Throws<ParseException>(() => fs());
 
-            var fFast = expr.CompileFast();
-            fFast.PrintIL("fast");
-            Asserts.Throws<ParseException>(() => fFast());
+            var ff = expr.CompileFast();
+            ff.PrintIL("fast");
+            Asserts.Throws<ParseException>(() => ff());
         }
 
 #if LIGHT_EXPRESSION

test/FastExpressionCompiler.TestsRunner/Program.cs

@@ -14,6 +14,7 @@ public static void Main()
             // ILGeneratorTools.DisableILGeneratorPooling = true;
             // LightExpression.ILGeneratorTools.DisableILGeneratorPooling = true;
 
+            new IssueTests.Issue316_in_parameter().Run();
             new LightExpression.IssueTests.Issue55_CompileFast_crash_with_ref_parameter().Run();
             new LightExpression.IssueTests.Issue341_Equality_comparison_between_nullable_and_null_inside_Any_produces_incorrect_compiled_expression().Run();
             new LightExpression.IssueTests.Issue347_InvalidProgramException_on_compiling_an_expression_that_returns_a_record_which_implements_IList().Run();