Add 'ResultOfAsyncCallShouldNotBeIgnored' issue.

ICSharpCode.NRefactory.CSharp/ICSharpCode.NRefactory.CSharp.csproj

@@ -316,6 +316,7 @@
     <Compile Include="Refactoring\CodeIssues\RedundantObjectOrCollectionInitializerIssue.cs" />
     <Compile Include="Refactoring\CodeIssues\RedundantTypeCastIssue.cs" />
     <Compile Include="Refactoring\CodeIssues\ReferenceEqualsCalledWithValueTypeIssue.cs" />
+    <Compile Include="Refactoring\CodeIssues\ResultOfAsyncCallShouldNotBeIgnoredIssue.cs" />
     <Compile Include="Refactoring\CodeIssues\UnreachableCodeIssue.cs" />
     <Compile Include="Refactoring\CodeIssues\VariableHidesMemberIssue\LocalVariableHidesMemberIssue.cs" />
     <Compile Include="Refactoring\CodeIssues\VariableHidesMemberIssue\ParameterHidesMemberIssue.cs" />

ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/ResultOfAsyncCallShouldNotBeIgnoredIssue.cs

@@ -0,0 +1,58 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using System.Collections.Generic;
+using ICSharpCode.NRefactory.Semantics;
+using ICSharpCode.NRefactory.TypeSystem;
+
+namespace ICSharpCode.NRefactory.CSharp.Refactoring
+{
+	[IssueDescription("Result of async call is ignored",
+	                  Description = "Warns when the task returned by an async call is ignored, which causes exceptions" +
+	                  " thrown by the call to be silently ignored.",
+	                  Category = IssueCategories.CodeQualityIssues,
+	                  Severity = Severity.Warning)]
+	public class ResultOfAsyncCallShouldNotBeIgnoredIssue : ICodeIssueProvider
+	{
+		public IEnumerable<CodeIssue> GetIssues(BaseRefactoringContext context)
+		{
+			return new GatherVisitor().GetIssues();
+		}
+		
+		sealed class GatherVisitor : GatherVisitorBase
+		{
+			public GatherVisitor(BaseRefactoringContext ctx)
+				: base(ctx)
+			{
+			}
+			
+			public override void VisitExpressionStatement(ExpressionStatement expressionStatement)
+			{
+				base.VisitExpressionStatement(expressionStatement);
+				var invocation = expressionStatement.Expression as InvocationExpression;
+				if (invocation == null)
+					return;
+				var rr = ctx.Resolve(invocation) as InvocationResolveResult;
+				if (rr != null && (rr.Type.IsKnownType(KnownTypeCode.Task) || rr.Type.IsKnownType(KnownTypeCode.TaskOfT))) {
+					AddIssue(invocation, "Exceptions in async call will be silently ignored because the returned task is unused");
+				}
+			}
+		}
+	}
+}

ICSharpCode.NRefactory/TypeSystem/Implementation/KnownTypeCache.cs

@@ -48,12 +48,13 @@ namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 			KnownTypeReference typeRef = KnownTypeReference.Get(typeCode);
 			if (typeRef == null)
 				return SpecialType.UnknownType;
+			var typeName = new TopLevelTypeName(typeRef.Namespace, typeRef.Name, typeRef.TypeParameterCount);
 			foreach (IAssembly asm in compilation.Assemblies) {
-				var typeDef = asm.GetTypeDefinition(new TopLevelTypeName(typeRef.Namespace, typeRef.Name, typeRef.TypeParameterCount));
+				var typeDef = asm.GetTypeDefinition(typeName);
 				if (typeDef != null)
 					return typeDef;
 			}
-			return new UnknownType(typeRef.Namespace, typeRef.Name, typeRef.TypeParameterCount);
+			return new UnknownType(typeName);
 		}
 	}
 }