fixed lambda return type nullability inference

simonrozsival · Apr 8, 2024 · 766f36d · 766f36d
1 parent 4923ac7
commit 766f36d
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Showing 4 changed files with 16 additions and 17 deletions.
diff --git a/src/Controls/src/BindingSourceGen/BindingSourceGenerator.cs b/src/Controls/src/BindingSourceGen/BindingSourceGenerator.cs
@@ -58,8 +58,10 @@ static bool IsSetBindingMethod(SyntaxNode node)
 	static BindingDiagnosticsWrapper GetBindingForGeneration(GeneratorSyntaxContext context, CancellationToken t)
 	{
 		var diagnostics = new List<Diagnostic>();
-		var invocation = (InvocationExpressionSyntax)context.Node;
+		NullableContext nullableContext = context.SemanticModel.GetNullableContext(context.Node.Span.Start);
+		var enabledNullable = (nullableContext & NullableContext.Enabled) == NullableContext.Enabled;
 
+		var invocation = (InvocationExpressionSyntax)context.Node;
 		var method = (MemberAccessExpressionSyntax)invocation.Expression;
 
 		var sourceCodeLocation = new SourceCodeLocation(
@@ -82,26 +84,23 @@ static BindingDiagnosticsWrapper GetBindingForGeneration(GeneratorSyntaxContext
 			return ReportDiagnostics(lambdaDiagnostics);
 		}
 
-		NullableContext nullableContext = context.SemanticModel.GetNullableContext(context.Node.Span.Start);
-		var enabledNullable = (nullableContext & NullableContext.Enabled) == NullableContext.Enabled;
+		var lambdaTypeInfo = context.SemanticModel.GetTypeInfo(lambdaBody, t);
+		if (lambdaTypeInfo.Type == null)
+		{
+			return ReportDiagnostics([DiagnosticsFactory.UnableToResolvePath(lambdaBody.GetLocation())]); // TODO: New diagnostic
+		}
 
 		var pathParser = new PathParser(context);
 		var (pathDiagnostics, parts) = pathParser.ParsePath(lambdaBody);
-
 		if (pathDiagnostics.Length > 0)
 		{
 			return ReportDiagnostics(pathDiagnostics);
 		}
 
-		// Sometimes analysing just the return type of the lambda is not enough. TODO: Refactor
-		// var propertyType = BindingGenerationUtilities.CreateTypeNameFromITypeSymbol(lambdaSymbol.ReturnType, enabledNullable);
-		// var lastMember = parts.Last() is Cast cast ? cast.Part : parts.Last();
-		// propertyType = propertyType with { IsNullable = lastMember is ConditionalAccess || propertyType.IsNullable };
-
 		var codeWriterBinding = new CodeWriterBinding(
 			Location: sourceCodeLocation,
 			SourceType: BindingGenerationUtilities.CreateTypeNameFromITypeSymbol(lambdaSymbol.Parameters[0].Type, enabledNullable),
-			PropertyType: BindingGenerationUtilities.CreateTypeNameFromITypeSymbol(lambdaSymbol.ReturnType, enabledNullable),
+			PropertyType: BindingGenerationUtilities.CreateTypeNameFromITypeSymbol(lambdaTypeInfo.Type, enabledNullable),
 			Path: parts.ToArray(),
 			GenerateSetter: false //TODO: Implement
 		);

diff --git a/src/Controls/tests/BindingSourceGen.UnitTests/BindingRepresentationGenTests.cs b/src/Controls/tests/BindingSourceGen.UnitTests/BindingRepresentationGenTests.cs
@@ -155,7 +155,7 @@ public void GenerateBindingWithNullableSourceReferenceAndNullableReferenceElemen
         AssertExtensions.BindingsAreEqual(expectedBinding, codeGeneratorResult);
     }
 
-    [Fact(Skip = "Require checking path for elements that can be null")]
+    [Fact]
     public void GenerateBindingWithNullablePropertyReferenceWhenNullableEnabled()
     {
         var source = """
@@ -299,7 +299,7 @@ class Foo
         AssertExtensions.BindingsAreEqual(expectedBinding, codeGeneratorResult);
     }
 
-    [Fact(Skip = "Requires checking path for casts")]
+    [Fact]
     public void GenerateBindingWhenGetterContainsSimpleReferenceTypeCast()
     {
         var source = """
@@ -309,15 +309,15 @@ public void GenerateBindingWhenGetterContainsSimpleReferenceTypeCast()
 
         class Foo
         {
-            public object Value { get; set; }
+            public object Value { get; set; } = "Value";
         }
         """;
 
         var codeGeneratorResult = SourceGenHelpers.Run(source);
         var expectedBinding = new CodeWriterBinding(
                 new SourceCodeLocation(@"Path\To\Program.cs", 3, 7),
                 new TypeDescription("global::Foo"),
-                new TypeDescription("string", IsNullable: true), // May be hard
+                new TypeDescription("string", IsNullable: true),
                 [
                     new Cast(
                         new MemberAccess("Value"),

diff --git a/src/Controls/tests/BindingSourceGen.UnitTests/IntegrationTests.cs b/src/Controls/tests/BindingSourceGen.UnitTests/IntegrationTests.cs
@@ -187,7 +187,7 @@ file static class GeneratedBindableObjectExtensions
                     public static void SetBinding1(
                         this BindableObject bindableObject,
                         BindableProperty bidnableProperty,
-                        Func<global::MyNamespace.MySourceClass, global::MyNamespace.MyPropertyClass> getter,
+                        Func<global::MyNamespace.MySourceClass, global::MyNamespace.MyPropertyClass?> getter,
                         BindingMode mode = BindingMode.Default,
                         IValueConverter? converter = null,
                         object? converterParameter = null,
@@ -196,7 +196,7 @@ public static void SetBinding1(
                         object? fallbackValue = null,
                         object? targetNullValue = null)
                     {
-                        var binding = new TypedBinding<global::MyNamespace.MySourceClass, global::MyNamespace.MyPropertyClass>(
+                        var binding = new TypedBinding<global::MyNamespace.MySourceClass, global::MyNamespace.MyPropertyClass?>(
                             getter: source => (getter(source), true),
                             setter: null,
                             handlers: new Tuple<Func<global::MyNamespace.MySourceClass, object?>, string>[]

diff --git a/src/Controls/tests/BindingSourceGen.UnitTests/SourceGenHelpers.cs b/src/Controls/tests/BindingSourceGen.UnitTests/SourceGenHelpers.cs
@@ -33,7 +33,7 @@ internal static CodeGeneratorResult Run(string source)
         var result = driver.RunGeneratorsAndUpdateCompilation(inputCompilation, out Compilation compilation, out _).GetRunResult().Results.Single();
 
         var generatedCodeDiagnostic = compilation.GetDiagnostics();
-        var generatedCode = result.GeneratedSources.Single().SourceText.ToString();
+        var generatedCode = result.GeneratedSources.Length == 1 ? result.GeneratedSources.Single().SourceText.ToString() : "";
 
         var trackedSteps = result.TrackedSteps;