Fixes for RoslynDeclarationProvider and Conversion.TryFindConversion (#271)

* RoslynDeclarationProvider uses all available source codes
to build the requested type declaration.

* Conversion.TryFindConversion looks for casts defined on the toType as
well.

Co-authored-by: Dmitry Kats <ratkillerx@hotmail.com>

src/Compiler/Dynamic/Conversion.cs

@@ -474,9 +474,9 @@ namespace Microsoft.ML.Probabilistic.Compiler.Reflection
                 }
             }
             // check for custom conversions
-            MemberInfo[] implicits = fromType.FindMembers(MemberTypes.Method, BindingFlags.Public | BindingFlags.Static | BindingFlags.InvokeMethod, Type.FilterName,
+            MemberInfo[] implicitsOnFromType = fromType.FindMembers(MemberTypes.Method, BindingFlags.Public | BindingFlags.Static | BindingFlags.InvokeMethod, Type.FilterName,
                                                           "op_Implicit");
-            foreach (MemberInfo member in implicits)
+            foreach (MemberInfo member in implicitsOnFromType)
             {
                 MethodInfo method = (MethodInfo) member;
                 if (method.ReturnType == toType)
@@ -489,9 +489,25 @@ namespace Microsoft.ML.Probabilistic.Compiler.Reflection
                     return true;
                 }
             }
-            MemberInfo[] explicits = fromType.FindMembers(MemberTypes.Method, BindingFlags.Public | BindingFlags.Static | BindingFlags.InvokeMethod, Type.FilterName,
+            MemberInfo[] implicitsOnToType = toType.FindMembers(MemberTypes.Method, BindingFlags.Public | BindingFlags.Static | BindingFlags.InvokeMethod, Type.FilterName,
+                                                          "op_Implicit");
+            foreach (MemberInfo member in implicitsOnToType)
+            {
+                MethodInfo method = (MethodInfo)member;
+                ParameterInfo[] parameters = method.GetParameters();
+                if (parameters.Length == 1 && parameters[0].ParameterType == fromType)
+                {
+                    info.SubclassCount = 1000;
+                    info.Converter = delegate (object value)
+                    {
+                        return Util.Invoke(method, null, value);
+                    };
+                    return true;
+                }
+            }
+            MemberInfo[] explicitsOnFromType = fromType.FindMembers(MemberTypes.Method, BindingFlags.Public | BindingFlags.Static | BindingFlags.InvokeMethod, Type.FilterName,
                                                           "op_Explicit");
-            foreach (MemberInfo member in explicits)
+            foreach (MemberInfo member in explicitsOnFromType)
             {
                 MethodInfo method = (MethodInfo) member;
                 if (method.ReturnType == toType)
@@ -504,6 +520,23 @@ namespace Microsoft.ML.Probabilistic.Compiler.Reflection
                     return true;
                 }
             }
+            MemberInfo[] explicitsOnToType = toType.FindMembers(MemberTypes.Method, BindingFlags.Public | BindingFlags.Static | BindingFlags.InvokeMethod, Type.FilterName,
+                                                          "op_Explicit");
+
+            foreach (MemberInfo member in explicitsOnToType)
+            {
+                MethodInfo method = (MethodInfo)member;
+                ParameterInfo[] parameters = method.GetParameters();
+                if (parameters.Length == 1 && parameters[0].ParameterType == fromType)
+                {
+                    info.IsExplicit = true;
+                    info.Converter = delegate (object value)
+                    {
+                        return Util.Invoke(method, null, value);
+                    };
+                    return true;
+                }
+            }
             // lastly try the IConvertible interface
             if (toType.IsPrimitive)
             {

src/Csoft/EmbeddedResourceSourceProvider.cs

@@ -4,10 +4,9 @@
 
 using System;
 using System.Collections.Generic;
+using System.Collections.Immutable;
 using System.IO;
 using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 
@@ -17,17 +16,9 @@ namespace Microsoft.ML.Probabilistic.Compiler
     {
         public SourceCode TryGetSource(Type t)
         {
-            var asm = t.Assembly;
-            return asm.GetManifestResourceNames().Where(s => s.EndsWith(".cs")).Select(s =>
+            bool IsPrimaryFile(SourceFile sf)
             {
-                var stream = asm.GetManifestResourceStream(s);
-                using (var reader = new StreamReader(stream))
-                {
-                    return new SourceCode(s, reader.ReadToEnd());
-                }
-            }).FirstOrDefault(code =>
-            {
-                var tree = CSharpSyntaxTree.ParseText(code.SourceText, null, code.FilePath);
+                var tree = CSharpSyntaxTree.ParseText(sf.SourceText, null, sf.FilePath);
                 var root = tree.GetRoot();
                 var typeDecl = root.DescendantNodes()
                                  .OfType<NamespaceDeclarationSyntax>()
@@ -38,7 +29,24 @@ namespace Microsoft.ML.Probabilistic.Compiler
                                  .Where(md => md.Identifier.ValueText.Equals(t.Name))
                                  .FirstOrDefault();
                 return typeDecl != null;
-            });
+            }
+            var asm = t.Assembly;
+            SourceFile primaryFile = null;
+            List<SourceFile> additionalFiles = new List<SourceFile>();
+            foreach (var s in asm.GetManifestResourceNames().Where(s => s.EndsWith(".cs")))
+            {
+                SourceFile sf;
+                var stream = asm.GetManifestResourceStream(s);
+                using (var reader = new StreamReader(stream))
+                {
+                    sf = new SourceFile(s, reader.ReadToEnd());
+                }
+                if (primaryFile == null && IsPrimaryFile(sf))
+                    primaryFile = sf;
+                else
+                    additionalFiles.Add(sf);
+            }
+            return primaryFile == null ? null : new SourceCode(primaryFile, additionalFiles.ToImmutableArray());
         }
     }
 }

src/Csoft/ISourceProvider.cs

@@ -3,25 +3,41 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
+using System.Collections.Immutable;
 
 namespace Microsoft.ML.Probabilistic.Compiler
 {
-    public class SourceCode
+    public class SourceFile
     {
         public string FilePath { get; }
         public string SourceText { get; }
 
-        public SourceCode(string filePath, string sourceText)
+        public SourceFile(string filePath, string sourceText)
         {
             FilePath = filePath;
             SourceText = sourceText;
         }
     }
 
+    public class SourceCode
+    {
+        /// <summary>
+        /// Source file that contains the primary definition.
+        /// </summary>
+        public SourceFile PrimaryFile { get; }
+        /// <summary>
+        /// Additional files that contain the definitions of some of the types referenced in the primary file.
+        /// Should be used to build a more complete semantic model.
+        /// </summary>
+        public ImmutableArray<SourceFile> AddtionalFiles { get; }
+
+        public SourceCode(SourceFile primaryFile, ImmutableArray<SourceFile> additionalFiles)
+        {
+            PrimaryFile = primaryFile;
+            AddtionalFiles = additionalFiles;
+        }
+    }
+
     public interface ISourceProvider
     {
         SourceCode TryGetSource(Type t);

src/Csoft/RoslynDeclarationProvider.cs

@@ -71,10 +71,12 @@ namespace Microsoft.ML.Probabilistic.Compiler
             var source = SourceProvider.TryGetSource(t);
             if (source == null)
                 throw new InvalidOperationException($"Cannot find source code for the type {t.Name}");
-            var tree = CSharpSyntaxTree.ParseText(source.SourceText, null, source.FilePath, Encoding.UTF8);
+            var primaryTree = CSharpSyntaxTree.ParseText(source.PrimaryFile.SourceText, null, source.PrimaryFile.FilePath, Encoding.UTF8);
+            var allTrees = source.AddtionalFiles.Select(f => CSharpSyntaxTree.ParseText(f.SourceText, null, f.FilePath, Encoding.UTF8)).ToList();
+            allTrees.Add(primaryTree);
             
             var options = new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary);
-            var targetAssemblyName = Path.GetFileNameWithoutExtension(tree.FilePath);
+            var targetAssemblyName = Path.GetFileNameWithoutExtension(primaryTree.FilePath);
             var asmName = t.Assembly.GetName();
             var pk = asmName.GetPublicKey();
             if (pk != null && pk.Length > 0)
@@ -86,8 +88,8 @@ namespace Microsoft.ML.Probabilistic.Compiler
                     .WithPublicSign(true)
                     .WithCryptoPublicKey(System.Collections.Immutable.ImmutableArray.Create(pk));
             }
-            var compilation = CSharpCompilation.Create(targetAssemblyName, new[] { tree }, references, options);
-            var model = compilation.GetSemanticModel(tree);
+            var compilation = CSharpCompilation.Create(targetAssemblyName, allTrees, references, options);
+            var model = compilation.GetSemanticModel(primaryTree);
 
             var errors = compilation.GetDiagnostics().ToList();
 

test/Tests/Dynamic/TypeInference.cs

@@ -143,6 +143,14 @@ namespace Microsoft.ML.Probabilistic.Tests
             Assert.True(Conversion.TryGetConversion(typeof (Tester), typeof (int[]), out conv));
             o = conv.Converter(t);
             Console.WriteLine("{0}: {1}", o.GetType(), o);
+            Assert.True(Conversion.TryGetConversion(typeof(int), typeof(Tester), out conv));
+            Assert.True(conv.IsExplicit);
+            Assert.True(Conversion.TryGetConversion(typeof(int[]), typeof(Tester), out conv));
+            Assert.True(conv.IsExplicit);
+            Assert.True(Conversion.TryGetConversion(typeof(ImplicitlyConvertibleToTesterDefinesCast), typeof(Tester), out conv));
+            Assert.False(conv.IsExplicit);
+            Assert.True(Conversion.TryGetConversion(typeof(ImplicitlyConvertibleToTesterCastDefinedOnTester), typeof(Tester), out conv));
+            Assert.False(conv.IsExplicit);
 
             // conversion from null
             Assert.False(Conversion.TryGetConversion(typeof (Nullable), typeof (int), out conv));
@@ -842,8 +850,35 @@ namespace Microsoft.ML.Probabilistic.Tests
           {
             return t.arrayField;
           }
+
+            public static explicit operator Tester(int x)
+            {
+                var tester = new Tester
+                {
+                    intField = x
+                };
+                return tester;
+            }
+
+            public static explicit operator Tester(int[] x)
+            {
+                var tester = new Tester
+                {
+                    arrayField = x
+                };
+                return tester;
+            }
+
+            public static implicit operator Tester(ImplicitlyConvertibleToTesterCastDefinedOnTester _) => new Tester();
         }
 
+        public class ImplicitlyConvertibleToTesterDefinesCast
+        {
+            public static implicit operator Tester(ImplicitlyConvertibleToTesterDefinesCast _) => new Tester();
+        }
+
+        public class ImplicitlyConvertibleToTesterCastDefinedOnTester { }
+
         /// <summary>
         /// Help class of dynamically invoking methods.
         /// </summary>

test/Tests/MslTests.cs

@@ -70,7 +70,6 @@ namespace Microsoft.ML.Probabilistic.Tests
 
         [Fact]
         [Trait("Category", "CsoftModel")]
-        [Trait("Category", "OpenBug")]
         public void MethodInAnotherFileTest()
         {
             Assert.Throws<CompilationFailedException>(() =>