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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.CodeFixes;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.CodeFixes.DeclareAsNullable;
using Microsoft.CodeAnalysis.Diagnostics;
using Microsoft.CodeAnalysis.Test.Utilities;
using Roslyn.Test.Utilities;
using Xunit;
using Xunit.Abstractions;
namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.Diagnostics.DeclareAsNullable
{
[Trait(Traits.Feature, Traits.Features.CodeActionsDeclareAsNullable)]
public class CSharpDeclareAsNullableCodeFixTests : AbstractCSharpDiagnosticProviderBasedUserDiagnosticTest
{
public CSharpDeclareAsNullableCodeFixTests(ITestOutputHelper logger)
: base(logger)
{
}
internal override (DiagnosticAnalyzer?, CodeFixProvider) CreateDiagnosticProviderAndFixer(Workspace workspace)
=> (null, new CSharpDeclareAsNullableCodeFixProvider());
private static readonly TestParameters s_nullableFeature = new TestParameters(parseOptions: new CSharpParseOptions(LanguageVersion.CSharp8));
[Fact]
public async Task FixAll()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
static string M()
{
return {|FixAllInDocument:null|};
}
static string M2(bool b)
{
if (b)
return null;
else
return null;
}
}
""",
"""
#nullable enable
class Program
{
static string? M()
{
return null;
}
static string? M2(bool b)
{
if (b)
return null;
else
return null;
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixReturnType()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
static string M()
{
return [|null|];
}
}
""",
"""
#nullable enable
class Program
{
static string? M()
{
return null;
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixReturnType_Async()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
static async System.Threading.Tasks.Task<string> M()
{
return [|null|];
}
}
""",
"""
#nullable enable
class Program
{
static async System.Threading.Tasks.Task<string?> M()
{
return null;
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixReturnType_AsyncLocalFunction()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
static void M()
{
async System.Threading.Tasks.Task<string> local()
{
return [|null|];
}
}
}
""",
"""
#nullable enable
class Program
{
static void M()
{
async System.Threading.Tasks.Task<string?> local()
{
return null;
}
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixReturnType_WithTrivia()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
static /*before*/ string /*after*/ M()
{
return [|null|];
}
}
""",
"""
#nullable enable
class Program
{
static /*before*/ string? /*after*/ M()
{
return null;
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixReturnType_ArrowBody()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
static string M() => [|null|];
}
""",
"""
#nullable enable
class Program
{
static string? M() => null;
}
""", parameters: s_nullableFeature);
}
[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/26639")]
public async Task FixReturnType_LocalFunction_ArrowBody()
{
await TestMissingInRegularAndScriptAsync(
"""
#nullable enable
class Program
{
static void M()
{
string local() => [|null|];
}
}
""", parameters: s_nullableFeature);
}
[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/26639")]
public async Task FixLocalFunctionReturnType()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
void M()
{
string local()
{
return [|null|];
}
}
}
""",
"""
#nullable enable
class Program
{
void M()
{
string? local()
{
return null;
}
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task NoFixAlreadyNullableReturnType()
{
await TestMissingInRegularAndScriptAsync(
"""
#nullable enable
class Program
{
static string? M()
{
return [|null|];
}
}
""", parameters: s_nullableFeature);
}
[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/26628")]
public async Task FixField()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
string x = [|null|];
}
""",
"""
#nullable enable
class Program
{
string? x = null;
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixFieldEqualsNull()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
string x;
void M()
{
x = [|null|];
}
}
""",
"""
#nullable enable
class Program
{
string? x;
void M()
{
x = null;
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixPropertyEqualsNull()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
string x { get; set; }
void M()
{
x = [|null|];
}
}
""",
"""
#nullable enable
class Program
{
string? x { get; set; }
void M()
{
x = null;
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixLocalDeclaration()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
static void M()
{
string x = [|null|];
}
}
""",
"""
#nullable enable
class Program
{
static void M()
{
string? x = null;
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixLocalDeclaration_FromAssignment()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
static void M()
{
string x = "";
x = [|null|];
}
}
""",
"""
#nullable enable
class Program
{
static void M()
{
string? x = "";
x = null;
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task CannotFixMultiLocalDeclaration_FromAssignment()
{
await TestMissingInRegularAndScriptAsync(
"""
#nullable enable
class Program
{
static void M()
{
string x, y;
x = [|null|];
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixParameter_FromAssignment()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
static void M(out string x)
{
x = [|null|];
}
}
""",
"""
#nullable enable
class Program
{
static void M(out string? x)
{
x = null;
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task CannotFixParameterOfPartialMethod_FromAssignment()
{
await TestMissingInRegularAndScriptAsync(
"""
#nullable enable
partial class Program
{
partial void M(out string x);
partial void M(out string x)
{
x = [|null|];
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task CannotFixParameterOfExtendedPartialMethod_FromAssignment()
{
await TestMissingInRegularAndScriptAsync(
"""
#nullable enable
partial class Program
{
public partial void M(out string x);
public partial void M(out string x)
{
x = [|null|];
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixLocalDeclaration_WithVar()
{
await TestMissingInRegularAndScriptAsync(
"""
#nullable enable
class Program
{
static void M()
{
var x = [|null|];
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task NoFixMultiDeclaration()
{
await TestMissingInRegularAndScriptAsync(
"""
#nullable enable
class Program
{
static void M()
{
string x = [|null|], y = null;
}
}
""", parameters: s_nullableFeature);
}
[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/26628")]
public async Task FixPropertyDeclaration()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
string x { get; set; } = [|null|];
}
""",
"""
#nullable enable
class Program
{
string? x { get; set; } = null;
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixPropertyDeclaration_WithReturnNull()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
string x { get { return [|null|]; } }
}
""",
"""
#nullable enable
class Program
{
string? x { get { return null; } }
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixPropertyDeclaration_ArrowBody()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
string x => [|null|];
}
""",
"""
#nullable enable
class Program
{
string? x => null;
}
""", parameters: s_nullableFeature);
}
[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/26626")]
[WorkItem("https://github.com/dotnet/roslyn/issues/30026")]
public async Task FixOptionalParameter()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
static void M(string x = [|null|]) { }
}
""",
"""
#nullable enable
class Program
{
static void M(string? x = null) { }
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixLocalWithAs()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
static void M(object o)
{
string x = [|o as string|];
}
}
""",
"""
#nullable enable
class Program
{
static void M(object o)
{
string? x = o as string;
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixReturnType_Iterator_Enumerable()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
static System.Collections.Generic.IEnumerable<string> M()
{
yield return [|null|];
}
}
""",
"""
#nullable enable
class Program
{
static System.Collections.Generic.IEnumerable<string?> M()
{
yield return null;
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixReturnType_Iterator_Enumerator()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
static System.Collections.Generic.IEnumerator<string> M()
{
yield return [|null|];
}
}
""",
"""
#nullable enable
class Program
{
static System.Collections.Generic.IEnumerator<string?> M()
{
yield return null;
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixReturnType_IteratorProperty()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
System.Collections.Generic.IEnumerable<string> Property
{
get
{
yield return [|null|];
}
}
}
""",
"""
#nullable enable
class Program
{
System.Collections.Generic.IEnumerable<string?> Property
{
get
{
yield return null;
}
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixReturnType_Iterator_LocalFunction()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
void M()
{
System.Collections.Generic.IEnumerable<string> local()
{
yield return [|null|];
}
}
}
""",
"""
#nullable enable
class Program
{
void M()
{
System.Collections.Generic.IEnumerable<string?> local()
{
yield return null;
}
}
}
""", parameters: s_nullableFeature);
}
[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/39422")]
public async Task FixReturnType_ConditionalOperator_Function()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
string Test(bool? value)
{
return [|value?.ToString()|];
}
}
""",
"""
#nullable enable
class Program
{
string? Test(bool? value)
{
return value?.ToString();
}
}
""", parameters: s_nullableFeature);
}
[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/39422")]
public async Task FixAllReturnType_ConditionalOperator_Function()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
string field;
string Property { get; set; }
string Test(bool? value)
{
return {|FixAllInDocument:value?.ToString()|};
}
string Test1(bool? value)
{
return value?.ToString();
}
string Test2(bool? value)
{
field = null;
Property = null;
return null;
}
}
""",
"""
#nullable enable
class Program
{
string field;
string Property { get; set; }
string? Test(bool? value)
{
return value?.ToString();
}
string? Test1(bool? value)
{
return value?.ToString();
}
string Test2(bool? value)
{
field = null;
Property = null;
return null;
}
}
""", parameters: s_nullableFeature);
}
[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/39422")]
public async Task FixAllReturnType_Invocation()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
string field;
string Property { get; set; }
void M(string value)
{
M({|FixAllInDocument:null|});
}
void M2(string value)
{
M2(null);
}
string Test(bool? value)
{
return value?.ToString();
}
string Test2(bool? value)
{
field = null;
Property = null;
return null;
}
}
""",
"""
#nullable enable
class Program
{
string? field;
string? Property { get; set; }
void M(string? value)
{
M(null);
}
void M2(string? value)
{
M2(null);
}
string Test(bool? value)
{
return value?.ToString();
}
string Test2(bool? value)
{
field = null;
Property = null;
return null;
}
}
""", parameters: s_nullableFeature);
}
[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/39420")]
public async Task FixReturnType_TernaryExpression_Function()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
string Test(bool value)
{
return [|value ? "text" : null|];
}
}
""",
"""
#nullable enable
class Program
{
string? Test(bool value)
{
return value ? "text" : null;
}
}
""", parameters: s_nullableFeature);
}
[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/39423")]
public async Task FixReturnType_Default()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
string Test()
{
return [|default|];
}
}
""",
"""
#nullable enable
class Program
{
string? Test()
{
return default;
}
}
""", parameters: s_nullableFeature);
}
[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/39423")]
public async Task FixReturnType_DefaultWithNullableType()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
string Test()
{
return [|default(string)|];
}
}
""",
"""
#nullable enable
class Program
{
string? Test()
{
return default(string);
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixInvocation_NamedArgument()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
void M()
{
M2(x: [|null|]);
}
void M2(string x) { }
}
""",
"""
#nullable enable
class Program
{
void M()
{
M2(x: null);
}
void M2(string? x) { }
}
""", parameters: s_nullableFeature);
}
[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/44338")]
public async Task NoFixInvocationOfExternalMethod_NamedArgument()
{
await TestMissingInRegularAndScriptAsync(
"""
#nullable enable
class Program
{
void M()
{
var list = new System.Collections.Generic.List<string>();
list.Add(item: [|null|]);
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixInvocation_NamedArgument_OutOfOrder()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
void M()
{
M2(x: [|null|], i: 1);
}
void M2(int i, string x) { }
}
""",
"""
#nullable enable
class Program
{
void M()
{
M2(x: null, i: 1);
}
void M2(int i, string? x) { }
}
""", parameters: s_nullableFeature);
}
[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/44338")]
public async Task NoFixInvocationOfExternalMethod_NamedArgument_OutOfOrder()
{
await TestMissingInRegularAndScriptAsync(
"""
#nullable enable
class Program
{
void M()
{
var dict = new System.Collections.Generic.Dictionary<string, int>();
dict.Add(value: 0, key: [|null|]);
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixInvocation_NamedArgument_Partial()
{
await TestMissingInRegularAndScriptAsync(
"""
#nullable enable
partial class Program
{
void M()
{
M2(x: [|null|]);
}
partial void M2(string x);
partial void M2(string x) { }
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixInvocation_PositionArgument()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
void M()
{
M2([|null|]);
}
void M2(string x) { }
}
""",
"""
#nullable enable
class Program
{
void M()
{
M2(null);
}
void M2(string? x) { }
}
""", parameters: s_nullableFeature);
}
[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/44338")]
public async Task NoFixInvocationOfExternalMethod_PositionArgument()
{
await TestMissingInRegularAndScriptAsync(
"""
#nullable enable
class Program
{
void M()
{
var list = new System.Collections.Generic.List<string>();
list.Add([|null|]);
}
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixInvocation_PositionArgument_SecondPosition()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
void M()
{
M2(1, [|null|]);
}
void M2(int i, string x) { }
}
""",
"""
#nullable enable
class Program
{
void M()
{
M2(1, null);
}
void M2(int i, string? x) { }
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixInvocation_PositionArgument_Params()
{
await TestMissingInRegularAndScriptAsync(
"""
#nullable enable
class Program
{
void M()
{
M2("", [|null|]);
}
void M2(params string[] x) { }
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixInvocation_Indexer()
{
// Not supported yet
await TestMissingInRegularAndScriptAsync(
"""
#nullable enable
class Program
{
void M()
{
this[[|null|]];
}
int this[string x] { get { throw null!; } set { throw null!; } }
}
""", parameters: s_nullableFeature);
}
[Fact]
public async Task FixPropertyDeclaration_Unassigned()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class C
{
string [|S|] { get; }
}
""",
"""
#nullable enable
class C
{
string? S { get; }
}
""",
parameters: s_nullableFeature);
}
[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/44983")]
public async Task FixFieldDeclaration_Unassigned()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class C
{
private string [|_value|];
}
""",
"""
#nullable enable
class C
{
private string? _value;
}
""",
parameters: s_nullableFeature);
}
[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/44983")]
public async Task MultipleDeclarator_NoDiagnostic()
{
await TestMissingInRegularAndScriptAsync(
"""
#nullable enable
class Program
{
string [|s|], s2 = "hello";
}
""", parameters: s_nullableFeature);
}
[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/46354")]
public async Task FixTupleFieldAssignment()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
static void F1((string, string?) t)
{
if (t.Item2 == null) return;
t.Item1 = [|null|];
}
}
""",
"""
#nullable enable
class Program
{
static void F1((string?, string?) t)
{
if (t.Item2 == null) return;
t.Item1 = null;
}
}
""", parameters: s_nullableFeature);
}
[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/46354")]
public async Task FixTupleNamedFieldAssignment()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
static void F1((string Foo, string? Bar) t)
{
if (t.Bar == null) return;
t.Foo = [|null|];
}
}
""",
"""
#nullable enable
class Program
{
static void F1((string? Foo, string? Bar) t)
{
if (t.Bar == null) return;
t.Foo = null;
}
}
""", parameters: s_nullableFeature);
}
[Fact, WorkItem("https://github.com/dotnet/roslyn/issues/46354")]
public async Task FixTupleGenericFieldAssignment()
{
await TestInRegularAndScript1Async(
"""
#nullable enable
class Program
{
static void F1<T>((T, T?) t) where T : class
{
if (t.Item2 == null) return;
t.Item1 = [|null|];
var (a, b) = t;
}
}
""",
"""
#nullable enable
class Program
{
static void F1<T>((T?, T?) t) where T : class
{
if (t.Item2 == null) return;
t.Item1 = null;
var (a, b) = t;
}
}
""", parameters: s_nullableFeature);
}
}
}
|