Support null! suppression of elements in a params argument

CollinAlpert · Nov 15, 2023 · b48dee4 · b48dee4
1 parent 30e6172
commit b48dee4
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Showing 2 changed files with 43 additions and 12 deletions.
diff --git a/src/nunit.analyzers.tests/TestCaseUsage/TestCaseUsageAnalyzerTests.cs b/src/nunit.analyzers.tests/TestCaseUsage/TestCaseUsageAnalyzerTests.cs
@@ -475,6 +475,32 @@ public void Test(object a) { }
             RoslynAssert.Valid(this.analyzer, testCode);
         }
 
+        [Test]
+        public void AnalyzeWhenArgumentPassesNullToNonNullableParamsReferenceType()
+        {
+            var testCode = TestUtility.WrapClassInNamespaceAndAddUsing(@"
+    public sealed class AnalyzeWhenArgumentPassesSuppressedNullToNonNullableType
+    {
+        [TestCase(""Hello"", null)]
+        public void Test(params string[] a) { }
+    }");
+            RoslynAssert.Diagnostics(this.analyzer,
+                ExpectedDiagnostic.Create(AnalyzerIdentifiers.TestCaseParameterTypeMismatchUsage),
+                testCode);
+        }
+
+        [Test]
+        public void AnalyzeWhenArgumentPassesSuppressedNullToNonNullableParamsReferenceType()
+        {
+            var testCode = TestUtility.WrapClassInNamespaceAndAddUsing(@"
+    public sealed class AnalyzeWhenArgumentPassesSuppressedNullToNonNullableType
+    {
+        [TestCase(""Hello"", null!)]
+        public void Test(params string[] a) { }
+    }");
+            RoslynAssert.Valid(this.analyzer, testCode);
+        }
+
         [Test]
         public void AnalyzeWhenArgumentPassesValueToNullableType()
         {

diff --git a/src/nunit.analyzers/TestCaseUsage/TestCaseUsageAnalyzer.cs b/src/nunit.analyzers/TestCaseUsage/TestCaseUsageAnalyzer.cs
@@ -180,27 +180,32 @@ private static void AnalyzePositionalArgumentsAndParameters(
 
                 ITypeSymbol? argumentType = attributeArgument.Type;
 
-                var argumentTypeMatchesParameterType = attributeArgument.CanAssignTo(
-                    methodParameterType,
-                    context.Compilation,
-                    allowImplicitConversion: true,
-                    allowEnumToUnderlyingTypeConversion: true,
-                    suppressNullableWarning: argumentSyntax.IsSuppressNullableWarning());
-
-                if (methodParameterParamsType is null && argumentTypeMatchesParameterType)
-                    continue;
+                if (i < methodParameters.Length)
+                {
+                    // Test against the actual parameter definition.
+                    // In case an array is passed to a params parameter.
+                    var argumentTypeMatchesParameterType = attributeArgument.CanAssignTo(
+                        methodParameterType,
+                        context.Compilation,
+                        allowImplicitConversion: true,
+                        allowEnumToUnderlyingTypeConversion: true,
+                        suppressNullableWarning: argumentSyntax.IsSuppressNullableWarning());
+
+                    if (argumentTypeMatchesParameterType)
+                        continue;
+                }
 
                 if (methodParameterParamsType is not null)
                 {
+                    // Test against the element type of the params parameter.
                     var argumentTypeMatchesElementType = attributeArgument.CanAssignTo(
                         methodParameterParamsType,
                         context.Compilation,
                         allowImplicitConversion: true,
                         allowEnumToUnderlyingTypeConversion: true,
-                        suppressNullableWarning: false);
+                        suppressNullableWarning: argumentSyntax.IsSuppressNullableWarning());
 
-                    if (argumentTypeMatchesElementType ||
-                        (argumentTypeMatchesParameterType && (argumentType is not null || !methodParameterParamsType.IsValueType)))
+                    if (argumentTypeMatchesElementType)
                     {
                         continue;
                     }