Merge pull request #511 from manfred-brands/issue509_TestCaseTypeMismatch

Do not report errors on TestCase parameters types that are invalid.

Author: mikkelbu

src/nunit.analyzers.tests/TestCaseUsage/TestCaseUsageAnalyzerTests.cs

@@ -355,6 +355,18 @@ public void Test(char a) { }
             RoslynAssert.Diagnostics(this.analyzer, expectedDiagnostic, testCode);
         }
 
+        [Test]
+        public void AnalyzeArgumentHasTypeNotAllowedInAttributes()
+        {
+            var testCode = TestUtility.WrapClassInNamespaceAndAddUsing(@"
+    class AnalyzeArgumentHasTypeNotAllowedInAttributes
+    {
+        [TestCase(1.0m)]
+        public void Test(decimal d) { }
+    }");
+            RoslynAssert.Valid(this.analyzer, testCode, Settings.Default.WithAllowedCompilerDiagnostics(AllowedCompilerDiagnostics.WarningsAndErrors));
+        }
+
         [Test]
         public void AnalyzeWhenArgumentPassesNullToValueType()
         {

src/nunit.analyzers/TestCaseUsage/TestCaseUsageAnalyzer.cs

@@ -179,6 +179,12 @@ private static void AnalyzePositionalArgumentsAndParameters(
             for (var i = 0; i < attributePositionalArguments.Length; i++)
             {
                 var attributeArgument = attributePositionalArguments[i];
+
+                // If the compiler detects an illegal constant, we shouldn't check it.
+                // Unfortunately the constant 'null' is marked as Error with a null type.
+                if (attributeArgument.Kind == TypedConstantKind.Error && attributeArgument.Type is not null)
+                    continue;
+
                 var (methodParameterType, methodParameterName, methodParameterParamsType) =
                     TestCaseUsageAnalyzer.GetParameterType(methodParameters, i);