[Fact]
        public void ListPattern_UseSiteErrorOnIndexerAndSlice()
        {
            var missing_cs = @"
public class Missing
{
}
";
            var missingRef = CreateCompilation(missing_cs, assemblyName: "missing")
                .EmitToImageReference();

            var lib2_cs = @"
public class C
{
    public int Length => 0;
    public Missing this[int i] => throw null;
    public Missing Slice(int i, int j) => throw null;
}
";
            var lib2Ref = CreateCompilation(lib2_cs, references: new[] { missingRef })
                .EmitToImageReference();

            var source = @"
class D
{
    void M(C c)
    {
        _ = c is { var item };
        _ = c is { ..var rest };
        var index = c[^1];
        var range = c[1..^1];
    }
}
";
            var compilation = CreateCompilation(new[] { source, TestSources.Index, TestSources.Range },
                references: new[] { lib2Ref }, parseOptions: TestOptions.RegularWithListPatterns);
            // PROTOTYPE missing diagnostics
            compilation.VerifyEmitDiagnostics(
                // (8,21): error CS0012: The type 'Missing' is defined in an assembly that is not referenced. You must add a reference to assembly 'missing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null'.
                //         var index = c[^1];
                Diagnostic(ErrorCode.ERR_NoTypeDef, "c[^1]").WithArguments("Missing", "missing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null").WithLocation(8, 21),
                // (9,21): error CS0012: The type 'Missing' is defined in an assembly that is not referenced. You must add a reference to assembly 'missing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null'.
                //         var range = c[1..^1];
                Diagnostic(ErrorCode.ERR_NoTypeDef, "c[1..^1]").WithArguments("Missing", "missing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null").WithLocation(9, 21)
                );


            var tree = compilation.SyntaxTrees.First();
            var model = compilation.GetSemanticModel(tree, ignoreAccessibility: false);
            var declarations = tree.GetRoot().DescendantNodes().OfType<VarPatternSyntax>().ToArray();

            verify(declarations[0], "item", "Missing?");
            verify(declarations[1], "rest", "Missing?");

            void verify(VarPatternSyntax declaration, string name, string expectedType)
            {
                var local = (ILocalSymbol)model.GetDeclaredSymbol(declaration.Designation)!;
                Assert.Equal(name, local.Name);
                Assert.Equal(expectedType, local.Type.ToTestDisplayString(includeNonNullable: true));
            }
        }
        
                [Fact]
        public void ListPattern_UseSiteErrorOnIndexAndRangeIndexers_WithFallback()
        {
            var missing_cs = @"
public class Missing
{
}
";
            var missingRef = CreateCompilation(missing_cs, assemblyName: "missing")
                .EmitToImageReference();

            var lib2_cs = @"
using System;
public class C
{
    public int Length => 0;
    public Missing this[Index i] => throw null;
    public Missing this[Range r] => throw null;
    public int this[int i] => throw null;
    public int Slice(int i, int j) => throw null;
}
";
            var lib2Ref = CreateCompilation(new[] { lib2_cs, TestSources.Index, TestSources.Range }, references: new[] { missingRef })
                .EmitToImageReference();

            var source = @"
class D
{
    void M(C c)
    {
        _ = c is { var item };
        _ = c is { ..var rest };
        var index = c[^1];
        var range = c[1..^1];
    }
}
";
            var compilation = CreateCompilation(source, references: new[] { lib2Ref }, parseOptions: TestOptions.RegularWithListPatterns);
            // PROTOTYPE binding for list and slice patterns should fail too
            compilation.VerifyEmitDiagnostics(
                // (8,21): error CS0012: The type 'Missing' is defined in an assembly that is not referenced. You must add a reference to assembly 'missing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null'.
                //         var index = c[^1];
                Diagnostic(ErrorCode.ERR_NoTypeDef, "c[^1]").WithArguments("Missing", "missing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null").WithLocation(8, 21),
                // (9,21): error CS0012: The type 'Missing' is defined in an assembly that is not referenced. You must add a reference to assembly 'missing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null'.
                //         var range = c[1..^1];
                Diagnostic(ErrorCode.ERR_NoTypeDef, "c[1..^1]").WithArguments("Missing", "missing, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null").WithLocation(9, 21)
                );
        }