From 1a7ca154b4f3033e716f6af7126d9394beb4491b Mon Sep 17 00:00:00 2001 From: Daniel Grunwald Date: Tue, 14 Feb 2012 11:54:47 +0100 Subject: [PATCH] Allow conversion of anonymous method with unreachable endpoint to Func. --- .../Analysis/ReachabilityAnalysis.cs | 82 +++++++++++++++++++ .../ICSharpCode.NRefactory.CSharp.csproj | 1 + .../Resolver/CSharpAstResolver.cs | 6 ++ .../Resolver/ResolveVisitor.cs | 22 +++-- .../CSharp/Resolver/LambdaTests.cs | 22 +++++ 5 files changed, 126 insertions(+), 7 deletions(-) create mode 100644 ICSharpCode.NRefactory.CSharp/Analysis/ReachabilityAnalysis.cs diff --git a/ICSharpCode.NRefactory.CSharp/Analysis/ReachabilityAnalysis.cs b/ICSharpCode.NRefactory.CSharp/Analysis/ReachabilityAnalysis.cs new file mode 100644 index 0000000000..e06c42490a --- /dev/null +++ b/ICSharpCode.NRefactory.CSharp/Analysis/ReachabilityAnalysis.cs @@ -0,0 +1,82 @@ +// 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 System.Threading; +using ICSharpCode.NRefactory.CSharp.Resolver; + +namespace ICSharpCode.NRefactory.CSharp.Analysis +{ + /// + /// Statement reachability analysis. + /// + public sealed class ReachabilityAnalysis + { + HashSet reachableStatements = new HashSet(); + HashSet reachableEndPoints = new HashSet(); + HashSet visitedNodes = new HashSet(); + Stack stack = new Stack(); + + private ReachabilityAnalysis() {} + + public static ReachabilityAnalysis Create(Statement statement, CSharpAstResolver resolver = null, CancellationToken cancellationToken = default(CancellationToken)) + { + var cfgBuilder = new ControlFlowGraphBuilder(); + var cfg = cfgBuilder.BuildControlFlowGraph(statement, resolver, cancellationToken); + return Create(cfg, cancellationToken); + } + + public static ReachabilityAnalysis Create(IList controlFlowGraph, CancellationToken cancellationToken = default(CancellationToken)) + { + if (controlFlowGraph == null) + throw new ArgumentNullException("controlFlowGraph"); + ReachabilityAnalysis ra = new ReachabilityAnalysis(); + ra.stack.Push(controlFlowGraph[0]); + while (ra.stack.Count > 0) { + cancellationToken.ThrowIfCancellationRequested(); + ra.MarkReachable(ra.stack.Pop()); + } + ra.stack = null; + ra.visitedNodes = null; + return ra; + } + + void MarkReachable(ControlFlowNode node) + { + if (node.PreviousStatement != null) + reachableEndPoints.Add(node.PreviousStatement); + if (node.NextStatement != null) + reachableStatements.Add(node.NextStatement); + foreach (var edge in node.Outgoing) { + if (visitedNodes.Add(edge.To)) + stack.Push(edge.To); + } + } + + public bool IsReachable(Statement statement) + { + return reachableStatements.Contains(statement); + } + + public bool IsEndpointReachable(Statement statement) + { + return reachableEndPoints.Contains(statement); + } + } +} diff --git a/ICSharpCode.NRefactory.CSharp/ICSharpCode.NRefactory.CSharp.csproj b/ICSharpCode.NRefactory.CSharp/ICSharpCode.NRefactory.CSharp.csproj index 83836ca089..1765288c78 100644 --- a/ICSharpCode.NRefactory.CSharp/ICSharpCode.NRefactory.CSharp.csproj +++ b/ICSharpCode.NRefactory.CSharp/ICSharpCode.NRefactory.CSharp.csproj @@ -60,6 +60,7 @@ + diff --git a/ICSharpCode.NRefactory.CSharp/Resolver/CSharpAstResolver.cs b/ICSharpCode.NRefactory.CSharp/Resolver/CSharpAstResolver.cs index 756d22ba6a..47525c3053 100644 --- a/ICSharpCode.NRefactory.CSharp/Resolver/CSharpAstResolver.cs +++ b/ICSharpCode.NRefactory.CSharp/Resolver/CSharpAstResolver.cs @@ -78,6 +78,12 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver this.resolveVisitor = new ResolveVisitor(initialResolverState, parsedFile); } + internal CSharpAstResolver(ResolveVisitor resolveVisitor) + { + this.resolveVisitor = resolveVisitor; + this.resolverInitialized = true; + } + /// /// Gets the type resolve context for the root resolver. /// diff --git a/ICSharpCode.NRefactory.CSharp/Resolver/ResolveVisitor.cs b/ICSharpCode.NRefactory.CSharp/Resolver/ResolveVisitor.cs index 59cf220389..31d441a07a 100644 --- a/ICSharpCode.NRefactory.CSharp/Resolver/ResolveVisitor.cs +++ b/ICSharpCode.NRefactory.CSharp/Resolver/ResolveVisitor.cs @@ -22,6 +22,7 @@ using System.Diagnostics; using System.Linq; using System.Text; using System.Threading; +using ICSharpCode.NRefactory.CSharp.Analysis; using ICSharpCode.NRefactory.CSharp.TypeSystem; using ICSharpCode.NRefactory.Semantics; using ICSharpCode.NRefactory.TypeSystem; @@ -1759,6 +1760,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver IList returnExpressions; IList returnValues; bool isValidAsVoidMethod; + bool isEndpointUnreachable; bool success; // The actual return type is set when the lambda is applied by the conversion. @@ -1820,7 +1822,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver delegate { var oldNavigator = visitor.navigator; visitor.navigator = new ConstantModeResolveVisitorNavigator(ResolveVisitorNavigationMode.Resolve, oldNavigator); - visitor.AnalyzeLambda(body, isAsync, out success, out isValidAsVoidMethod, out inferredReturnType, out returnExpressions, out returnValues); + visitor.AnalyzeLambda(body, isAsync, out success, out isValidAsVoidMethod, out isEndpointUnreachable, out inferredReturnType, out returnExpressions, out returnValues); visitor.navigator = oldNavigator; }); Log.Unindent(); @@ -1836,7 +1838,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver { Log.WriteLine("Testing validity of {0} for return-type {1}...", this, returnType); Log.Indent(); - bool valid = Analyze() && IsValidLambda(isValidAsVoidMethod, isAsync, returnValues, returnType, conversions); + bool valid = Analyze() && IsValidLambda(isValidAsVoidMethod, isEndpointUnreachable, isAsync, returnValues, returnType, conversions); Log.Unindent(); Log.WriteLine("{0} is {1} for return-type {2}", this, valid ? "valid" : "invalid", returnType); if (valid) { @@ -2103,6 +2105,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver IList returnExpressions; IList returnValues; bool isValidAsVoidMethod; + bool isEndpointUnreachable; internal bool success; public LambdaTypeHypothesis(ImplicitlyTypedLambda lambda, IType[] parameterTypes, ResolveVisitor visitor, @@ -2135,7 +2138,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver } } - visitor.AnalyzeLambda(lambda.BodyExpression, lambda.IsAsync, out success, out isValidAsVoidMethod, out inferredReturnType, out returnExpressions, out returnValues); + visitor.AnalyzeLambda(lambda.BodyExpression, lambda.IsAsync, out success, out isValidAsVoidMethod, out isEndpointUnreachable, out inferredReturnType, out returnExpressions, out returnValues); visitor.resolver = oldResolver; Log.Unindent(); Log.WriteLine("Finished analyzing " + ToString()); @@ -2153,7 +2156,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver public Conversion IsValid(IType returnType, Conversions conversions) { - if (success && IsValidLambda(isValidAsVoidMethod, lambda.IsAsync, returnValues, returnType, conversions)) { + if (success && IsValidLambda(isValidAsVoidMethod, isEndpointUnreachable, lambda.IsAsync, returnValues, returnType, conversions)) { return new AnonymousFunctionConversion(returnType, this); } else { return Conversion.None; @@ -2285,8 +2288,9 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver return SpecialType.UnknownType; } - void AnalyzeLambda(AstNode body, bool isAsync, out bool success, out bool isValidAsVoidMethod, out IType inferredReturnType, out IList returnExpressions, out IList returnValues) + void AnalyzeLambda(AstNode body, bool isAsync, out bool success, out bool isValidAsVoidMethod, out bool isEndpointUnreachable, out IType inferredReturnType, out IList returnExpressions, out IList returnValues) { + isEndpointUnreachable = false; Expression expr = body as Expression; if (expr != null) { isValidAsVoidMethod = ExpressionPermittedAsStatement(expr); @@ -2314,6 +2318,10 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver inferredReturnType = ti.GetBestCommonType(returnValues, out tiSuccess); // Failure to infer a return type does not make the lambda invalid, // so we can ignore the 'tiSuccess' value + if (isValidAsVoidMethod && returnExpressions.Count == 0 && body is Statement) { + var reachabilityAnalysis = ReachabilityAnalysis.Create((Statement)body, new CSharpAstResolver(this), cancellationToken); + isEndpointUnreachable = !reachabilityAnalysis.IsEndpointReachable((Statement)body); + } } } if (isAsync) @@ -2344,7 +2352,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver || expr is AssignmentExpression; } - static bool IsValidLambda(bool isValidAsVoidMethod, bool isAsync, IList returnValues, IType returnType, Conversions conversions) + static bool IsValidLambda(bool isValidAsVoidMethod, bool isEndpointUnreachable, bool isAsync, IList returnValues, IType returnType, Conversions conversions) { if (returnType.Kind == TypeKind.Void) { // Lambdas that are valid statement lambdas or expression lambdas with a statement-expression @@ -2356,7 +2364,7 @@ namespace ICSharpCode.NRefactory.CSharp.Resolver return isValidAsVoidMethod; } else { if (returnValues.Count == 0) - return false; + return isEndpointUnreachable; if (isAsync) { // async lambdas must return Task if (!(IsTask(returnType) && returnType.TypeParameterCount == 1)) diff --git a/ICSharpCode.NRefactory.Tests/CSharp/Resolver/LambdaTests.cs b/ICSharpCode.NRefactory.Tests/CSharp/Resolver/LambdaTests.cs index 7ba7a5f597..6c5286cf67 100644 --- a/ICSharpCode.NRefactory.Tests/CSharp/Resolver/LambdaTests.cs +++ b/ICSharpCode.NRefactory.Tests/CSharp/Resolver/LambdaTests.cs @@ -446,6 +446,28 @@ class Test { Assert.IsTrue(c.IsValid); } + [Test] + public void ThrowingAnonymousMethodIsConvertibleToFunc() + { + string program = @"using System; +class Test { + Func x = $delegate { throw new NotImplementedException(); }$; +}"; + var c = GetConversion(program); + Assert.IsTrue(c.IsValid); + } + + [Test] + public void EmptyAnonymousMethodIsNotConvertibleToFunc() + { + string program = @"using System; +class Test { + Func x = $delegate { }$; +}"; + var c = GetConversion(program); + Assert.IsFalse(c.IsValid); + } + [Test] public void RaisePropertyChanged_WithExpressionLambda() {