feat#550401: Support new .net language feature: tuple names (#618)

* Support new .net language feature: tuple names

* update test case

* update test case

* update

* updated

* update test case

* add debug info

* update

* Remove console log

7 files changed, 87 insertions, 3 deletions

diff --git a/mdoc/Consts.cs b/mdoc/Consts.cs
index 3ef0b936..4d2ef7c3 100644
--- a/mdoc/Consts.cs
+++ b/mdoc/Consts.cs
@@ -49,5 +49,6 @@ namespace Mono.Documentation
         public const string IsByRefLikeAttribute = "System.Runtime.CompilerServices.IsByRefLikeAttribute";
         public const string IsReadOnlyAttribute = "System.Runtime.CompilerServices.IsReadOnlyAttribute";
         public const string InAttribute = "System.Runtime.InteropServices.InAttribute";
+        public const string TupleElementNamesAttribute = "System.Runtime.CompilerServices.TupleElementNamesAttribute";
     }
 }
diff --git a/mdoc/Mono.Documentation/Updater/AttributeParserContext.cs b/mdoc/Mono.Documentation/Updater/AttributeParserContext.cs
index de9ee35d..e294d7cb 100644
--- a/mdoc/Mono.Documentation/Updater/AttributeParserContext.cs
+++ b/mdoc/Mono.Documentation/Updater/AttributeParserContext.cs
@@ -3,6 +3,7 @@ using Mono.Cecil;
 using Mono.Documentation.Util;
 using System;
 using System.Collections.ObjectModel;
+using System.Linq;
 
 namespace Mono.Documentation.Updater
 {
@@ -10,9 +11,11 @@ namespace Mono.Documentation.Updater
     {
         private int nullableAttributeIndex;
         private int dynamicAttributeIndex;
+        private int tupleNameAttributeIndex;
         private ICustomAttributeProvider provider;
         private ReadOnlyCollection<bool?> nullableAttributeFlags;
         private ReadOnlyCollection<bool> dynamicAttributeFlags;
+        private string[] tupleElementNames;
 
         private AttributeParserContext(ICustomAttributeProvider provider)
         {
@@ -20,6 +23,7 @@ namespace Mono.Documentation.Updater
 
             ReadDynamicAttribute();
             ReadNullableAttribute();
+            ReadTupleElementNames();
         }
 
         private bool ExistsNullableAttribute
@@ -73,6 +77,11 @@ namespace Mono.Documentation.Updater
             return false;
         }
 
+        public string GetTupleElementName()
+        {
+            return (tupleElementNames == null || tupleNameAttributeIndex >= tupleElementNames.Length) ? null : tupleElementNames[tupleNameAttributeIndex++];
+        }
+
         private void ReadDynamicAttribute()
         {
             DynamicTypeProvider dynamicTypeProvider = new DynamicTypeProvider(provider);
@@ -88,5 +97,18 @@ namespace Mono.Documentation.Updater
             NullableReferenceTypeProvider nullableReferenceTypeProvider = new NullableReferenceTypeProvider(provider);
             nullableAttributeFlags = new ReadOnlyCollection<bool?>(nullableReferenceTypeProvider.GetNullableReferenceTypeFlags());
         }
+
+        private void ReadTupleElementNames()
+        {
+            if (provider != null && provider.HasCustomAttributes)
+            {
+                var tupleNamesAttr = provider.CustomAttributes.Where(attr => attr.AttributeType.FullName == Consts.TupleElementNamesAttribute).FirstOrDefault();
+                if (tupleNamesAttr != null)
+                {
+                    var constructorArgs = tupleNamesAttr.ConstructorArguments.FirstOrDefault().Value as CustomAttributeArgument[];
+                    tupleElementNames = constructorArgs?.Select(arg => arg.Value as string).ToArray();
+                }
+            }
+        }
     }
 }
\ No newline at end of file
diff --git a/mdoc/Mono.Documentation/Updater/EmptyAttributeParserContext.cs b/mdoc/Mono.Documentation/Updater/EmptyAttributeParserContext.cs
index 87aecaa4..71b638fd 100644
--- a/mdoc/Mono.Documentation/Updater/EmptyAttributeParserContext.cs
+++ b/mdoc/Mono.Documentation/Updater/EmptyAttributeParserContext.cs
@@ -26,5 +26,10 @@
         {
             return false;
         }
+
+        public string GetTupleElementName()
+        {
+            return null;
+        }
     }
 }
diff --git a/mdoc/Mono.Documentation/Updater/Formatters/CSharpFullMemberFormatter.cs b/mdoc/Mono.Documentation/Updater/Formatters/CSharpFullMemberFormatter.cs
index 811ff3be..e885df57 100644
--- a/mdoc/Mono.Documentation/Updater/Formatters/CSharpFullMemberFormatter.cs
+++ b/mdoc/Mono.Documentation/Updater/Formatters/CSharpFullMemberFormatter.cs
@@ -137,7 +137,9 @@ namespace Mono.Documentation.Updater.Formatters
             if (genInst.Name.StartsWith ("ValueTuple`"))
             {
                 buf.Append ("(");
-                var genArgList = new List<string> ();
+                var genArgTypeList = new List<string> ();
+                // tuple element names should be traversed before recursion.
+                var genArgNameList = genInst.GenericArguments.Select(arg => context.GetTupleElementName()).ToList();
                 foreach (var item in genInst.GenericArguments)
                 {
                     var isNullableType = false;
@@ -147,11 +149,11 @@ namespace Mono.Documentation.Updater.Formatters
                     }
 
                     var underlyingTypeName = GetTypeName (item, context, appendGeneric, useTypeProjection) + GetTypeNullableSymbol (item, isNullableType);
-                    genArgList.Add (underlyingTypeName);
+                    genArgTypeList.Add (underlyingTypeName);
                 }
+                var genArgList = genInst.GenericArguments.Select((_, index) => string.Format("{0}{1}", genArgTypeList[index], genArgNameList[index] == null ? String.Empty : (" " + genArgNameList[index])));
                 buf.Append (string.Join (",", genArgList));
                 buf.Append (")");
-
                 return buf;
             }
 
diff --git a/mdoc/Mono.Documentation/Updater/IAttributeParserContext.cs b/mdoc/Mono.Documentation/Updater/IAttributeParserContext.cs
index aca6ba21..471c661b 100644
--- a/mdoc/Mono.Documentation/Updater/IAttributeParserContext.cs
+++ b/mdoc/Mono.Documentation/Updater/IAttributeParserContext.cs
@@ -5,5 +5,6 @@
         void NextDynamicFlag();
         bool IsDynamic();
         bool IsNullable();
+        string GetTupleElementName();
     }
 }
diff --git a/mdoc/mdoc.Test/FormatterTests.cs b/mdoc/mdoc.Test/FormatterTests.cs
index ce1009fe..868def32 100644
--- a/mdoc/mdoc.Test/FormatterTests.cs
+++ b/mdoc/mdoc.Test/FormatterTests.cs
@@ -420,6 +420,39 @@ namespace mdoc.Test
             Assert.AreEqual(expectedSignature, methodSignature);
         }
 
+        [Test]
+        public void CSharpTupleNamesTypeTest()
+        {
+            var type = GetType(typeof(SampleClasses.TupleNamesTestClass<,>));
+            var typeSignature = formatter.GetDeclaration(type);
+            Assert.AreEqual("public class TupleNamesTestClass<T1,T2> : IComparable<(T1,T2)>", typeSignature);
+        }
+
+        [Test]
+        public void CSharpTupleNamesPropertyTest()
+        {
+            var property = GetProperty(typeof(SampleClasses.TupleNamesTestClass<,>), m => m.Name == "TuplePropertyType");
+            var propertySignature = formatter.GetDeclaration(property);
+            Assert.AreEqual("public (int a,int b) TuplePropertyType { get; }", propertySignature);
+        }
+
+        [Test]
+        public void CSharpTupleNamesFieldTest()
+        {
+            var field = GetField(GetType(typeof(SampleClasses.TupleNamesTestClass<,>)), "TupleField");
+            var fieldSignature = formatter.GetDeclaration(field);
+            Assert.AreEqual("public (int a,int b,int c) TupleField;", fieldSignature);
+        }
+
+        [TestCase("TupleMethod", "public (int a,int,int b) TupleMethod ((int,int) t1, (int b,int c,int d) t2, (int,int) t3);")]
+        [TestCase("RecursiveTupleMethod", "public ((int a,long b) c,int d) RecursiveTupleMethod ((((int a,long) b,string c) d,(int e,(float f,float g) h) i,int j) t);")]
+        public void CSharpTupleNamesMethodTest(string methodName, string expectedSignature)
+        {
+            var method = GetMethod(typeof(SampleClasses.TupleNamesTestClass<,>), m => m.Name == methodName);
+            var methodSignature = formatter.GetDeclaration(method);
+            Assert.AreEqual(expectedSignature, methodSignature);
+        }
+
         #region Helper Methods
         string RealTypeName(string name){
             switch (name) {
diff --git a/mdoc/mdoc.Test/SampleClasses/TupleNamesTestClass.cs b/mdoc/mdoc.Test/SampleClasses/TupleNamesTestClass.cs
new file mode 100644
index 00000000..29b3a1e6
--- /dev/null
+++ b/mdoc/mdoc.Test/SampleClasses/TupleNamesTestClass.cs
@@ -0,0 +1,20 @@
+using System;
+
+namespace mdoc.Test.SampleClasses
+{
+    public class TupleNamesTestClass<T1, T2> : IComparable<ValueTuple<T1, T2>>
+    {
+        public (int a, int b) TuplePropertyType { get; }
+
+        public (int a, int b, int c) TupleField;
+
+        public (int a, int, int b) TupleMethod((int, int) t1, (int b, int c, int d) t2, ValueTuple<int, int> t3) => (t1.Item1, t2.b, t3.Item2);
+
+        public ((int a, long b) c, int d) RecursiveTupleMethod((((int a, long) b, string c) d, (int e, (float f, float g) h) i, int j) t) => (t.d.b, t.j);
+
+        public int CompareTo((T1, T2) other)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}
\ No newline at end of file