Omnisharp VS Code Issue 1814 Fix

src/OmniSharp.Roslyn.CSharp/Services/Signatures/InvocationContext.cs

@@ -1,13 +1,35 @@
+using System.Collections.Generic;
+using System.Linq;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 
+
 namespace OmniSharp.Roslyn.CSharp.Services.Signatures
 {
     internal class InvocationContext
     {
         public SemanticModel SemanticModel { get; set; }
         public int Position { get; set; }
         public SyntaxNode Receiver { get; set; }
-        public ArgumentListSyntax ArgumentList { get; set; }
-    }
+        public IEnumerable<TypeInfo> ArgumentTypes { get; set; }
+        public IEnumerable<SyntaxToken> Separators { get; set; }
+
+        public InvocationContext(SemanticModel SemModel,int Pos,SyntaxNode Rec, ArgumentListSyntax ArgList)
+        {
+            SemanticModel = SemModel;
+            Position = Pos;
+            Receiver = Rec;
+            ArgumentTypes = ArgList.Arguments.Select(argument => SemModel.GetTypeInfo(argument.Expression));
+            Separators = ArgList.Arguments.GetSeparators();
+        }
+        public InvocationContext(SemanticModel SemModel, int Pos, SyntaxNode Rec, AttributeArgumentListSyntax ArgList)
+        {
+            SemanticModel = SemModel;
+            Position = Pos;
+            Receiver = Rec;
+            ArgumentTypes = ArgList.Arguments.Select(argument => SemModel.GetTypeInfo(argument.Expression));
+            Separators = ArgList.Arguments.GetSeparators();
+        }
+    }  
 }
+

src/OmniSharp.Roslyn.CSharp/Services/Signatures/SignatureHelpService.cs

@@ -42,7 +42,7 @@ public async Task<SignatureHelpResponse> Handle(SignatureHelpRequest request)
             var response = new SignatureHelpResponse();
 
             // define active parameter by position
-            foreach (var comma in invocations.First().ArgumentList.Arguments.GetSeparators())
+            foreach (var comma in invocations.First().Separators)
             {
                 if (comma.Span.Start > invocations.First().Position)
                 {
@@ -58,9 +58,7 @@ public async Task<SignatureHelpResponse> Handle(SignatureHelpRequest request)
 
             foreach (var invocation in invocations)
             {
-                var types = invocation.ArgumentList.Arguments
-                    .Select(argument => invocation.SemanticModel.GetTypeInfo(argument.Expression));
-
+                var types = invocation.ArgumentTypes;
                 foreach (var methodOverload in GetMethodOverloads(invocation.SemanticModel, invocation.Receiver))
                 {
                     var signature = BuildSignature(methodOverload);
@@ -74,7 +72,6 @@ public async Task<SignatureHelpResponse> Handle(SignatureHelpRequest request)
                     }
                 }
             }
-
             var signaturesList = signaturesSet.ToList();
             response.Signatures = signaturesList;
             response.ActiveSignature = signaturesList.IndexOf(bestScoredItem);
@@ -96,30 +93,23 @@ private async Task<InvocationContext> GetInvocation(Document document, Request r
                 var invocation = node as InvocationExpressionSyntax;
                 if (invocation != null && invocation.ArgumentList.Span.Contains(position))
                 {
-                    return new InvocationContext()
-                    {
-                        SemanticModel = await document.GetSemanticModelAsync(),
-                        Position = position,
-                        Receiver = invocation.Expression,
-                        ArgumentList = invocation.ArgumentList
-                    };
+                    var semanticModel = await document.GetSemanticModelAsync();
+                    return new InvocationContext(semanticModel, position, invocation.Expression, invocation.ArgumentList);
                 }
-
                 var objectCreation = node as ObjectCreationExpressionSyntax;
                 if (objectCreation != null && objectCreation.ArgumentList.Span.Contains(position))
                 {
-                    return new InvocationContext()
-                    {
-                        SemanticModel = await document.GetSemanticModelAsync(),
-                        Position = position,
-                        Receiver = objectCreation,
-                        ArgumentList = objectCreation.ArgumentList
-                    };
+                    var semanticModel = await document.GetSemanticModelAsync();
+                    return new InvocationContext(semanticModel, position, objectCreation,objectCreation.ArgumentList);
+                }
+                var attributeSyntax = node as AttributeSyntax;
+                if (attributeSyntax != null && attributeSyntax.ArgumentList.Span.Contains(position))
+                {
+                    var semanticModel = await document.GetSemanticModelAsync();
+                    return new InvocationContext(semanticModel, position, attributeSyntax, attributeSyntax.ArgumentList);
                 }
-
                 node = node.Parent;
             }
-
             return null;
         }
 

tests/OmniSharp.Roslyn.CSharp.Tests/SignatureHelpFacts.cs

@@ -115,7 +115,7 @@ public async Task TestForParameterLabels()
     public static void Main(){
         Foo($$);
     }
-    pubic static Foo(bool b, int n = 1234)
+    public static Foo(bool b, int n = 1234)
     {
     }
 }";
@@ -152,6 +152,105 @@ private int Foo(int one, int two, int three)
             Assert.Equal(0, actual.ActiveParameter);
         }
 
+        [Fact]
+        public async Task SignatureHelpforAttributeCtorSingleParam()
+        {
+            const string source =
+@"using System;
+[MyTest($$)]
+public class TestClass 
+{
+    int value;
+
+    public static void Main()
+    {
+        var attributes= typeof(TestClass).CustomAttributes;
+        foreach (var attribute in attributes)
+        {
+            Console.WriteLine(attribute);
+        }
+    }
+    void TestMethod(int value)
+    {
+        this.value = value;
+    }
+}
+public class MyTestAttribute : Attribute 
+{
+    int value;
+    public MyTestAttribute(int value)
+    {
+        this.value = value;
+    }
+}";
+            var actual = await GetSignatureHelp(source);    
+            Assert.Equal(0, actual.ActiveParameter);
+
+            var signature = actual.Signatures.ElementAt(0);
+            Assert.Single(signature.Parameters);
+            Assert.Equal("value", signature.Parameters.ElementAt(0).Name);
+            Assert.Equal("int value", signature.Parameters.ElementAt(0).Label);
+        }
+        [Fact]
+        public async Task SignatureHelpforAttributeCtorMultipleParam()
+        {
+            const string source =
+@"using System;
+[MyTest($$)]
+public class TestClass 
+{
+    public static void Main()
+    {
+    }
+}
+public class MyTestAttribute : Attribute 
+{
+    int value1;
+    double value2;
+    public MyTestAttribute(int value1,double value2)
+    {
+        this.value1 = value1;
+        this.value2 = value2;
+    }
+}
+";
+            var actual = await GetSignatureHelp(source);
+            Assert.Equal(0, actual.ActiveParameter);
+
+            var signature = actual.Signatures.ElementAt(0);
+            Assert.Equal(2, signature.Parameters.Count());
+            Assert.Equal("value1", signature.Parameters.ElementAt(0).Name);
+            Assert.Equal("int value1", signature.Parameters.ElementAt(0).Label);
+            Assert.Equal("value2", signature.Parameters.ElementAt(1).Name);
+            Assert.Equal("double value2", signature.Parameters.ElementAt(1).Label);
+        }
+
+        [Fact]
+        public async Task SignatureHelpforAttributeCtorNoParam()
+        {
+            const string source =
+@"using System;
+[MyTest($$)]
+public class TestClass 
+{
+    public static void Main()
+    {
+    }
+}
+public class MyTestAttribute : Attribute 
+{
+    public MyTestAttribute()
+    {
+    }
+}";
+            var actual = await GetSignatureHelp(source);
+            Assert.Single(actual.Signatures);
+            Assert.Equal(0, actual.ActiveParameter);
+            Assert.Equal(0, actual.ActiveSignature);
+            Assert.Equal("MyTestAttribute", actual.Signatures.ElementAt(0).Name);
+            Assert.Empty(actual.Signatures.ElementAt(0).Parameters);
+        }
+
         [Fact]
         public async Task ActiveParameterIsBasedOnComma2()
         {