Runtime90357 6012

src/NetAnalyzers/Core/Microsoft.NetCore.Analyzers/Runtime/ProvideCorrectArgumentsToFormattingMethods.cs

@@ -65,6 +65,13 @@ public override void Initialize(AnalysisContext context)
 
                     int expectedStringFormatArgumentCount = GetFormattingArguments(stringFormat);
 
+                    if (expectedStringFormatArgumentCount < 0)
+                    {
+                        // Malformed format specification
+                        operationContext.ReportDiagnostic(operationContext.Operation.Syntax.CreateDiagnostic(Rule));
+                        return;
+                    }
+
                     // explicit parameter case
                     if (info.ExpectedStringFormatArgumentCount >= 0)
                     {
@@ -82,6 +89,11 @@ public override void Initialize(AnalysisContext context)
 
                         return;
                     }
+                    else if (info.ExpectedStringFormatArgumentCount == -2)
+                    {
+                        // Not a formatting method, we only checked the format specification.
+                        return;
+                    }
 
                     // ensure argument is an array
                     IArgumentOperation paramsArgument = invocation.Arguments[info.FormatStringIndex + 1];
@@ -424,6 +436,13 @@ private bool TryGetFormatInfo(IMethodSymbol method, int formatIndex, [NotNullWhe
 
             private static int GetExpectedNumberOfArguments(ImmutableArray<IParameterSymbol> parameters, int formatIndex)
             {
+                if (formatIndex == parameters.Length - 1)
+                {
+                    // format specification is the last parameter (e.g. CompositeFormat.Parse)
+                    // this is therefore not a formatting method.
+                    return -2;
+                }
+
                 // check params
                 IParameterSymbol nextParameter = parameters[formatIndex + 1];
                 if (nextParameter.IsParams)

src/NetAnalyzers/UnitTests/Microsoft.NetCore.Analyzers/Runtime/ProvideCorrectArgumentsToFormattingMethodsTests.cs

@@ -573,6 +573,70 @@ End Class"
             await basicTest.RunAsync();
         }
 
+        [Fact]
+        [WorkItem(90357, "https://github.com/dotnet/runtime/issues/90357")]
+        public async Task CA2241CSharpPassingMethodWithNoPossibleArguments()
+        {
+            var csharpTest = new VerifyCS.Test
+            {
+                TestState =
+                {
+                    Sources =
+                    {
+                        @"
+using System.Diagnostics.CodeAnalysis;
+
+class Test
+{
+    public static int Parse([StringSyntax(StringSyntaxAttribute.CompositeFormat)] string format) => -1;
+
+    void M1(string param)
+    {
+        var a = Parse(""{0} {1}"");
+    }
+}"
+                    },
+                    ReferenceAssemblies = ReferenceAssemblies.Net.Net70,
+                }
+            };
+
+            await csharpTest.RunAsync();
+        }
+
+        [Fact]
+        [WorkItem(90357, "https://github.com/dotnet/runtime/issues/90357")]
+        public async Task CA2241CSharpFailingMethodWithNoPossibleArgumentsButInValidFormat()
+        {
+            var csharpTest = new VerifyCS.Test
+            {
+                TestState =
+                {
+                    Sources =
+                    {
+                        @"
+using System.Diagnostics.CodeAnalysis;
+
+class Test
+{
+    public static int Parse([StringSyntax(StringSyntaxAttribute.CompositeFormat)] string format) => -1;
+
+    void M1(string param)
+    {
+        var a = Parse(""{0 {1}"");
+    }
+}"
+                    },
+                    ReferenceAssemblies = ReferenceAssemblies.Net.Net70,
+                }
+            };
+
+            csharpTest.ExpectedDiagnostics.Add(
+                // Test0.cs(10,17): warning CA2241: Provide correct arguments to formatting methods
+                GetBasicResultAt(10, 17));
+
+            await csharpTest.RunAsync();
+        }
+
         #endregion
 
         private static DiagnosticResult GetCSharpResultAt(int line, int column)