Added verification to highlight records which have a vtable but no co…

…nstructors since they can't be initialized from C# yet. Relates to #31
MochiLibraries · Dec 19, 2021 · 357f884 · 357f884
1 parent 8b453cb
commit 357f884
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diff --git a/Biohazrd.CSharp/#Transformations/CSharpTranslationVerifier.cs b/Biohazrd.CSharp/#Transformations/CSharpTranslationVerifier.cs
@@ -1,6 +1,7 @@
 using Biohazrd.CSharp.Metadata;
 using Biohazrd.Expressions;
 using Biohazrd.Transformation;
+using ClangSharp;
 using ClangSharp.Pathogen;
 using System.Collections.Immutable;
 using System.Linq;
@@ -298,6 +299,13 @@ protected override TransformationResult TransformRecord(TransformationContext co
             else if (declaration.VTable is not null && declaration.VTableField is null)
             { declaration = declaration.WithError("Records should not have a VTable without a VTable field."); }
 
+            // We don't currently provide a way to initialize a virtual type without a constructor
+            // https://github.com/MochiLibraries/Biohazrd/issues/31
+            if (declaration.VTable is not null
+                && !declaration.Members.OfType<TranslatedFunction>().Any(f => f.SpecialFunctionKind is SpecialFunctionKind.Constructor)
+                && declaration.Declaration is not CXXRecordDecl { IsAbstract: true })
+            { declaration = declaration.WithWarning("Virtual records without a constructor cannot be initialized from C#. See https://github.com/MochiLibraries/Biohazrd/issues/31"); }
+
             return base.TransformRecord(context, declaration);
         }
 

diff --git a/Tests/Biohazrd.CSharp.Tests/CSharpTranslationVerifierTests.cs b/Tests/Biohazrd.CSharp.Tests/CSharpTranslationVerifierTests.cs
@@ -385,5 +385,63 @@ public void Constant_UnsupportedConstantNotOk()
             // Unsupported constants should mention the failure reason
             Assert.Single(constant.Diagnostics.Where(d => d.Message.Contains(nameof(Constant_UnsupportedConstantNotOk))));
         }
+
+        [Fact]
+        [RelatedIssue("https://github.com/MochiLibraries/Biohazrd/issues/31")]
+        public void Record_CannotInitializeConstructorlessVirtual()
+        {
+            TranslatedLibrary library = CreateLibrary
+            (@"
+class MyClass
+{
+public:
+    virtual void Test() { }
+};
+"
+            );
+
+            Assert.Empty(library.FindDeclaration<TranslatedRecord>("MyClass").Diagnostics);
+            library = new CSharpTranslationVerifier().Transform(library);
+            Assert.Contains(library.FindDeclaration<TranslatedRecord>("MyClass").Diagnostics, d => d.Severity >= Severity.Warning);
+        }
+
+        [Fact]
+        [RelatedIssue("https://github.com/MochiLibraries/Biohazrd/issues/31")]
+        public void Record_CannotInitializeConstructorlessVirtual_IgnoreAbstract()
+        {
+            TranslatedLibrary library = CreateLibrary
+            (@"
+class MyClass
+{
+public:
+    virtual void Test() = 0;
+};
+"
+            );
+
+            Assert.Empty(library.FindDeclaration<TranslatedRecord>("MyClass").Diagnostics);
+            library = new CSharpTranslationVerifier().Transform(library);
+            Assert.Empty(library.FindDeclaration<TranslatedRecord>("MyClass").Diagnostics);
+        }
+
+        [Fact]
+        [RelatedIssue("https://github.com/MochiLibraries/Biohazrd/issues/31")]
+        public void Record_CannotInitializeConstructorlessVirtual_ExplicitConstructorOk()
+        {
+            TranslatedLibrary library = CreateLibrary
+            (@"
+class MyClass
+{
+public:
+    MyClass() { }
+    virtual void Test() { }
+};
+"
+            );
+
+            Assert.Empty(library.FindDeclaration<TranslatedRecord>("MyClass").Diagnostics);
+            library = new CSharpTranslationVerifier().Transform(library);
+            Assert.Empty(library.FindDeclaration<TranslatedRecord>("MyClass").Diagnostics);
+        }
     }
 }