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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.
#nullable disable
using System.Collections.Generic;
using System.Linq;
using Microsoft.CodeAnalysis.CSharp.Test.Utilities;
using Roslyn.Test.Utilities;
using Xunit;
namespace Microsoft.CodeAnalysis.CSharp.UnitTests
{
public class FlowDiagnosticTests : FlowTestBase
{
[Fact]
public void TestBug12350()
{
// We suppress the "local variable is only written" warning if the
// variable is assigned a non-constant value.
string program = @"
class Program
{
static int X() { return 1; }
static void M()
{
int i1 = 123; // 0219
int i2 = X(); // no warning
int? i3 = 123; // 0219
int? i4 = null; // 0219
int? i5 = X(); // no warning
int i6 = default(int); // 0219
int? i7 = default(int?); // 0219
int? i8 = new int?(); // 0219
int i9 = new int(); // 0219
}
}";
CreateCompilation(program).VerifyDiagnostics(
// (7,13): warning CS0219: The variable 'i1' is assigned but its value is never used
// int i1 = 123; // 0219
Diagnostic(ErrorCode.WRN_UnreferencedVarAssg, "i1").WithArguments("i1"),
// (9,14): warning CS0219: The variable 'i3' is assigned but its value is never used
// int? i3 = 123; // 0219
Diagnostic(ErrorCode.WRN_UnreferencedVarAssg, "i3").WithArguments("i3"),
// (10,14): warning CS0219: The variable 'i4' is assigned but its value is never used
// int? i4 = null; // 0219
Diagnostic(ErrorCode.WRN_UnreferencedVarAssg, "i4").WithArguments("i4"),
// (12,13): warning CS0219: The variable 'i6' is assigned but its value is never used
// int i6 = default(int); // 0219
Diagnostic(ErrorCode.WRN_UnreferencedVarAssg, "i6").WithArguments("i6"),
// (13,14): warning CS0219: The variable 'i7' is assigned but its value is never used
// int? i7 = default(int?); // 0219
Diagnostic(ErrorCode.WRN_UnreferencedVarAssg, "i7").WithArguments("i7"),
// (14,14): warning CS0219: The variable 'i8' is assigned but its value is never used
// int? i8 = new int?(); // 0219
Diagnostic(ErrorCode.WRN_UnreferencedVarAssg, "i8").WithArguments("i8"),
// (15,13): warning CS0219: The variable 'i9' is assigned but its value is never used
// int i9 = new int(); // 0219
Diagnostic(ErrorCode.WRN_UnreferencedVarAssg, "i9").WithArguments("i9"));
}
[Fact]
public void Test1()
{
string program = @"
namespace ConsoleApplication1
{
class Program
{
public static void F(int z)
{
int x;
if (z == 2)
{
int y = x; x = y; // use of unassigned local variable 'x'
}
else
{
int y = x; x = y; // diagnostic suppressed here
}
}
}
}";
CreateCompilation(program).VerifyDiagnostics(
// (11,25): error CS0165: Use of unassigned local variable 'x'
// int y = x; x = y; // use of unassigned local variable 'x'
Diagnostic(ErrorCode.ERR_UseDefViolation, "x").WithArguments("x")
);
}
[Fact]
public void Test2()
{
//x is "assigned when true" after "false"
//Therefore x is "assigned" before "z == 1" (5.3.3.24)
//Therefore x is "assigned" after "z == 1" (5.3.3.20)
//Therefore x is "assigned when true" after "(false && z == 1)" (5.3.3.24)
//Since the condition of the ?: expression is the constant true, the state of x after the ?: expression is the same as the state of x after the consequence (5.3.3.28)
//Since the state of x after the consequence is "assigned when true", the state of x after the ?: expression is "assigned when true" (5.3.3.28)
//Since the state of x after the if's condition is "assigned when true", x is assigned in the then block (5.3.3.5)
//Therefore, there should be no error.
string program = @"
namespace ConsoleApplication1
{
class Program
{
void F(int z)
{
int x;
if (true ? (false && z == 1) : true)
x = x + 1; // Dev10 complains x not assigned.
}
}
}";
var comp = CreateCompilation(program);
var errs = this.FlowDiagnostics(comp);
Assert.Equal(0, errs.Count());
}
[Fact]
public void Test3()
{
string program = @"
class Program
{
int F(int z)
{
}
}";
var comp = CreateCompilation(program);
var errs = this.FlowDiagnostics(comp);
Assert.Equal(1, errs.Count());
}
[Fact]
public void Test4()
{
// v is definitely assigned at the beginning of any unreachable statement.
string program = @"
class Program
{
void F()
{
if (false)
{
int x; // warning: unreachable code
x = x + 1; // no error: x assigned when unreachable
}
}
}";
var comp = CreateCompilation(program);
int[] count = new int[4];
foreach (var e in this.FlowDiagnostics(comp))
count[(int)e.Severity]++;
Assert.Equal(0, count[(int)DiagnosticSeverity.Error]);
Assert.Equal(1, count[(int)DiagnosticSeverity.Warning]);
Assert.Equal(0, count[(int)DiagnosticSeverity.Info]);
}
[Fact]
public void Test5()
{
// v is definitely assigned at the beginning of any unreachable statement.
string program = @"
class A
{
static void F()
{
goto L2;
goto L1; // unreachable code detected
int x;
L1: ; // Roslyn: extrs warning CS0162 -unreachable code
x = x + 1; // no definite assignment problem in unreachable code
L2: ;
}
}
";
var comp = CreateCompilation(program);
int[] count = new int[4];
foreach (var e in this.FlowDiagnostics(comp))
count[(int)e.Severity]++;
Assert.Equal(0, count[(int)DiagnosticSeverity.Error]);
Assert.Equal(2, count[(int)DiagnosticSeverity.Warning]);
Assert.Equal(0, count[(int)DiagnosticSeverity.Info]);
}
[WorkItem(537918, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/537918")]
[Fact]
public void AssertForInvalidBreak()
{
// v is definitely assigned at the beginning of any unreachable statement.
string program = @"
public class Test
{
public static int Main()
{
int ret = 1;
break; // Assert here
return (ret);
}
}
";
var comp = CreateCompilation(program);
comp.GetMethodBodyDiagnostics().Verify(
// (7,9): error CS0139: No enclosing loop out of which to break or continue
// break; // Assert here
Diagnostic(ErrorCode.ERR_NoBreakOrCont, "break;"));
}
[WorkItem(538064, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/538064")]
[Fact]
public void IfFalse()
{
string program = @"
using System;
class Program
{
static void Main()
{
if (false)
{
}
}
}";
var comp = CreateCompilation(program);
Assert.Equal(0, this.FlowDiagnostics(comp).Count());
}
[WorkItem(538067, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/538067")]
[Fact]
public void WhileConstEqualsConst()
{
string program = @"
using System;
class Program
{
bool goo()
{
const bool b = true;
while (b == b)
{
return b;
}
}
static void Main()
{
}
}";
var comp = CreateCompilation(program);
Assert.Equal(0, this.FlowDiagnostics(comp).Count());
}
[WorkItem(538175, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/538175")]
[Fact]
public void BreakWithoutTarget()
{
string program = @"public class Test
{
public static void Main()
{
if (true)
break;
}
}";
var comp = CreateCompilation(program);
Assert.Equal(0, this.FlowDiagnostics(comp).Count());
}
[Fact]
public void OutCausesAssignment()
{
string program = @"class Program
{
void F(out int x)
{
G(out x);
}
void G(out int x)
{
x = 1;
}
}";
var comp = CreateCompilation(program);
Assert.Equal(0, this.FlowDiagnostics(comp).Count());
}
[Fact]
public void OutNotAssigned01()
{
string program = @"class Program
{
bool b;
void F(out int x)
{
if (b) return;
}
}";
var comp = CreateCompilation(program);
Assert.Equal(2, this.FlowDiagnostics(comp).Count());
}
[WorkItem(539374, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/539374")]
[Fact]
public void OutAssignedAfterCall01()
{
string program = @"class Program
{
void F(out int x, int y)
{
x = y;
}
void G()
{
int x;
F(out x, x);
}
}";
var comp = CreateCompilation(program);
Assert.Equal(1, this.FlowDiagnostics(comp).Count());
}
[WorkItem(538067, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/538067")]
[Fact]
public void WhileConstEqualsConst2()
{
string program = @"
using System;
class Program
{
bool goo()
{
const bool b = true;
while (b == b)
{
return b;
}
return b; // Should detect this line as unreachable code.
}
static void Main()
{
}
}";
var comp = CreateCompilation(program);
int[] count = new int[4];
foreach (var e in this.FlowDiagnostics(comp))
count[(int)e.Severity]++;
Assert.Equal(0, count[(int)DiagnosticSeverity.Error]);
Assert.Equal(1, count[(int)DiagnosticSeverity.Warning]);
Assert.Equal(0, count[(int)DiagnosticSeverity.Info]);
}
[WorkItem(538072, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/538072")]
[Fact]
public void UnusedLocal()
{
string program = @"
using System;
class Program
{
int x; int y; int z;
static void Main()
{
int a;
const bool b = true;
}
void goo()
{
y = 2;
Console.WriteLine(z);
}
}";
var comp = CreateCompilation(program);
int[] count = new int[4];
Dictionary<int, int> warnings = new Dictionary<int, int>();
foreach (var e in this.FlowDiagnostics(comp))
{
count[(int)e.Severity]++;
if (!warnings.ContainsKey(e.Code)) warnings[e.Code] = 0;
warnings[e.Code] += 1;
}
Assert.Equal(0, count[(int)DiagnosticSeverity.Error]);
Assert.Equal(0, count[(int)DiagnosticSeverity.Info]);
// See bug 3562 - field level flow analysis warnings CS0169, CS0414 and CS0649 are out of scope for M2.
// TODO: Fix this test once CS0169, CS0414 and CS0649 are implemented.
// Assert.Equal(5, count[(int)DiagnosticSeverity.Warning]);
Assert.Equal(2, count[(int)DiagnosticSeverity.Warning]);
Assert.Equal(1, warnings[168]);
Assert.Equal(1, warnings[219]);
// See bug 3562 - field level flow analysis warnings CS0169, CS0414 and CS0649 are out of scope for M2.
// TODO: Fix this test once CS0169, CS0414 and CS0649 are implemented.
// Assert.Equal(1, warnings[169]);
// Assert.Equal(1, warnings[414]);
// Assert.Equal(1, warnings[649]);
}
[WorkItem(538384, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/538384")]
[Fact]
public void UnusedLocalConstants()
{
string program = @"
using System;
class Program
{
static void Main()
{
const string CONST1 = ""hello""; // Should not report CS0219
Console.WriteLine(CONST1 != ""hello"");
int i = 1;
const long CONST2 = 1;
const uint CONST3 = 1; // Should not report CS0219
while (CONST2 < CONST3 - i)
{
if (CONST3 < CONST3 - i) continue;
}
}
}";
var comp = CreateCompilation(program);
Assert.Equal(0, this.FlowDiagnostics(comp).Count());
}
[WorkItem(538385, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/538385")]
[Fact]
public void UnusedLocalReferenceTypedVariables()
{
string program = @"
using System;
class Program
{
static void Main()
{
object o = 1; // Should not report CS0219
Test c = new Test(); // Should not report CS0219
c = new Program();
string s = string.Empty; // Should not report CS0219
s = null;
}
}";
var comp = CreateCompilation(program);
Assert.Equal(0, this.FlowDiagnostics(comp).Count());
}
[WorkItem(538386, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/538386")]
[Fact]
public void UnusedLocalValueTypedVariables()
{
string program = @"
using System;
class Program
{
static void Main()
{
}
public void Repro2(params int[] x)
{
int i = x[0]; // Should not report CS0219
byte b1 = 1;
byte b11 = b1; // Should not report CS0219
}
}";
var comp = CreateCompilation(program);
Assert.Equal(0, this.FlowDiagnostics(comp).Count());
}
[Fact]
public void RefParameter01()
{
string program = @"
class Program
{
public static void Main(string[] args)
{
int i;
F(ref i); // use of unassigned local variable 'i'
}
static void F(ref int i) { }
}";
var comp = CreateCompilation(program);
Assert.NotEmpty(this.FlowDiagnostics(comp).Where(e => e.Severity >= DiagnosticSeverity.Error));
}
[Fact]
public void OutParameter01()
{
string program = @"
class Program
{
public static void Main(string[] args)
{
int i;
F(out i);
int j = i;
}
static void F(out int i) { i = 1; }
}";
var comp = CreateCompilation(program);
Assert.Empty(this.FlowDiagnostics(comp).Where(e => e.Severity >= DiagnosticSeverity.Error));
}
[Fact]
public void Goto01()
{
string program = @"
using System;
class Program
{
public void M(bool b)
{
if (b) goto label;
int i;
i = 3;
i = i + 1;
label:
int j = i; // i not definitely assigned
}
}";
var comp = CreateCompilation(program);
Assert.NotEmpty(this.FlowDiagnostics(comp).Where(e => e.Severity >= DiagnosticSeverity.Error));
}
[Fact]
public void LambdaParameters()
{
string program = @"
using System;
class Program
{
delegate void Func(ref int i, int r);
static void Main(string[] args)
{
Func fnc = (ref int arg, int arg2) => { arg = arg; };
}
}";
var comp = CreateCompilation(program);
Assert.Empty(this.FlowDiagnostics(comp).Where(e => e.Severity >= DiagnosticSeverity.Error));
}
[Fact]
public void LambdaMightNotBeInvoked()
{
string program = @"
class Program
{
delegate void Func();
static void Main(string[] args)
{
int i;
Func query = () =>
{
i = 12;
};
int j = i;
}
}";
var comp = CreateCompilation(program);
Assert.NotEmpty(this.FlowDiagnostics(comp).Where(e => e.Severity >= DiagnosticSeverity.Error));
}
[Fact]
public void LambdaMustAssignOutParameters()
{
string program = @"
class Program
{
delegate void Func(out int x);
static void Main(string[] args)
{
Func query = (out int x) =>
{
};
}
}";
var comp = CreateCompilation(program);
Assert.NotEmpty(this.FlowDiagnostics(comp).Where(e => e.Severity >= DiagnosticSeverity.Error));
}
[Fact, WorkItem(528052, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/528052")]
public void InnerVariablesAreNotDefinitelyAssignedInBeginningOfLambdaBody()
{
string program = @"
using System;
class Program
{
static void Main()
{
return;
Action f = () => { int y = y; };
}
}";
CreateCompilation(program).VerifyDiagnostics(
// (9,9): warning CS0162: Unreachable code detected
// Action f = () => { int y = y; };
Diagnostic(ErrorCode.WRN_UnreachableCode, "Action"),
// (9,36): error CS0165: Use of unassigned local variable 'y'
// Action f = () => { int y = y; };
Diagnostic(ErrorCode.ERR_UseDefViolation, "y").WithArguments("y")
);
}
[WorkItem(540139, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/540139")]
[Fact]
public void DelegateCreationReceiverIsRead()
{
string program = @"
using System;
class Program
{
static void Main()
{
Action a;
Func<string> b = new Func<string>(a.ToString);
}
}
";
var comp = CreateCompilation(program);
Assert.NotEmpty(this.FlowDiagnostics(comp).Where(e => e.Severity >= DiagnosticSeverity.Error));
}
[WorkItem(540405, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/540405")]
[Fact]
public void ErrorInFieldInitializerLambda()
{
string program = @"
using System;
class Program
{
static Func<string> x = () => { string s; return s; };
static void Main()
{
}
}
";
CreateCompilation(program).VerifyDiagnostics(
// (6,54): error CS0165: Use of unassigned local variable 's'
// static Func<string> x = () => { string s; return s; };
Diagnostic(ErrorCode.ERR_UseDefViolation, "s").WithArguments("s")
);
}
[WorkItem(541389, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/541389")]
[Fact]
public void IterationWithEmptyBody()
{
string program = @"
public class A
{
public static void Main(string[] args)
{
for (int i = 0; i < 10; i++) ;
foreach (var v in args);
int len = args.Length;
while (len-- > 0);
}
}";
CreateCompilation(program).VerifyDiagnostics();
}
[WorkItem(541389, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/541389")]
[Fact]
public void SelectionWithEmptyBody()
{
string program = @"
public class A
{
public static void Main(string[] args)
{
int len = args.Length;
if (len++ < 9) ; else ;
}
}";
CreateCompilation(program).VerifyDiagnostics(
Diagnostic(ErrorCode.WRN_PossibleMistakenNullStatement, ";"),
Diagnostic(ErrorCode.WRN_PossibleMistakenNullStatement, ";"));
}
[WorkItem(542146, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/542146")]
[Fact]
public void FieldlikeEvent()
{
string program = @"public delegate void D();
public struct S
{
public event D Ev;
public S(D d)
{
Ev = null;
Ev += d;
}
}";
CreateCompilation(program).VerifyDiagnostics(
// (4,20): warning CS0414: The field 'S.Ev' is assigned but its value is never used
// public event D Ev;
Diagnostic(ErrorCode.WRN_UnreferencedFieldAssg, "Ev").WithArguments("S.Ev"));
}
[WorkItem(542187, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/542187")]
[Fact]
public void GotoFromTry()
{
string program =
@"class Test
{
static void F(int x) { }
static void Main()
{
int a;
try
{
a = 1;
goto L1;
}
finally
{
}
L1:
F(a);
}
}";
CreateCompilation(program).VerifyDiagnostics();
}
[WorkItem(542154, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/542154")]
[Fact]
public void UnreachableThrow()
{
string program =
@"public class C
{
static void Main()
{
return;
throw Goo();
}
static System.Exception Goo()
{
System.Console.WriteLine(""Hello"");
return null;
}
}
";
CreateCompilation(program).VerifyDiagnostics();
}
[WorkItem(542585, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/542585")]
[Fact]
public void Bug9870()
{
string program =
@"
struct S<T>
{
T x;
static void Goo()
{
x.x = 1;
}
}";
var comp = CreateCompilation(program);
comp.VerifyDiagnostics(
// (8,9): error CS0120: An object reference is required for the non-static field, method, or property 'S<T>.x'
// x.x = 1;
Diagnostic(ErrorCode.ERR_ObjectRequired, "x").WithArguments("S<T>.x")
);
}
[WorkItem(542597, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/542597")]
[Fact]
public void LambdaEntryPointIsReachable()
{
string program =
@"class Program
{
static void Main(string[] args)
{
int i;
return;
System.Action a = () =>
{
int j = i + j;
};
}
}";
var comp = CreateCompilation(program);
comp.VerifyDiagnostics(
// unreachable statement
// (7,23): warning CS0162: Unreachable code detected
// System.Action a = () =>
Diagnostic(ErrorCode.WRN_UnreachableCode, "System"),
// (9,25): error CS0165: Use of unassigned local variable 'j'
// int j = i + j;
Diagnostic(ErrorCode.ERR_UseDefViolation, "j").WithArguments("j")
);
}
[WorkItem(542597, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/542597")]
[Fact]
public void LambdaInUnimplementedPartial()
{
string program =
@"using System;
partial class C
{
static partial void Goo(Action a);
static void Main()
{
Goo(() => { int x, y = x; });
}
}";
var comp = CreateCompilation(program);
comp.VerifyDiagnostics(
// (9,32): error CS0165: Use of unassigned local variable 'x'
// Goo(() => { int x, y = x; });
Diagnostic(ErrorCode.ERR_UseDefViolation, "x").WithArguments("x")
);
}
[WorkItem(541887, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/541887")]
[Fact]
public void CascadedDiagnostics01()
{
string program =
@"
class Program
{
static void Main(string[] args)
{
var s = goo<,int>(123);
}
public static int goo<T>(int i)
{
return 1;
}
}";
var comp = CreateCompilation(program);
var parseErrors = comp.SyntaxTrees[0].GetDiagnostics();
var errors = comp.GetDiagnostics();
Assert.Equal(parseErrors.Count(), errors.Count());
}
[Fact]
public void UnassignedInInitializer()
{
string program =
@"class C
{
System.Action a = () => { int i; int j = i; };
}";
var comp = CreateCompilation(program);
comp.VerifyDiagnostics(
// (3,46): error CS0165: Use of unassigned local variable 'i'
// System.Action a = () => { int i; int j = i; };
Diagnostic(ErrorCode.ERR_UseDefViolation, "i").WithArguments("i")
);
}
[WorkItem(543343, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/543343")]
[Fact]
public void ConstInSwitch()
{
string program =
@"class Program
{
static void Main(string[] args)
{
switch (args.Length)
{
case 0:
const int N = 3;
break;
case 1:
int M = N;
break;
}
}
}";
var comp = CreateCompilation(program);
comp.VerifyDiagnostics(
// (11,21): warning CS0219: The variable 'M' is assigned but its value is never used
// int M = N;
Diagnostic(ErrorCode.WRN_UnreferencedVarAssg, "M").WithArguments("M")
);
}
#region "Struct"
[Fact]
public void CycleWithInitialization()
{
string program = @"
public struct A
{
A a = new A(); // CS8036
public static void Main()
{
A a = new A();
}
}
";
CreateCompilation(program, parseOptions: TestOptions.Regular9).VerifyDiagnostics(
// (4,7): error CS8773: Feature 'struct field initializers' is not available in C# 9.0. Please use language version 10.0 or greater.
// A a = new A(); // CS8036
Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, "a").WithArguments("struct field initializers", "10.0").WithLocation(4, 7),
// (2,15): error CS8983: A 'struct' with field initializers must include an explicitly declared constructor.
// public struct A
Diagnostic(ErrorCode.ERR_StructHasInitializersAndNoDeclaredConstructor, "A").WithLocation(2, 15),
// (4,7): error CS0523: Struct member 'A.a' of type 'A' causes a cycle in the struct layout
// A a = new A(); // CS8036
Diagnostic(ErrorCode.ERR_StructLayoutCycle, "a").WithArguments("A.a", "A").WithLocation(4, 7),
// (7,11): warning CS0219: The variable 'a' is assigned but its value is never used
// A a = new A();
Diagnostic(ErrorCode.WRN_UnreferencedVarAssg, "a").WithArguments("a").WithLocation(7, 11),
// (4,7): warning CS0169: The field 'A.a' is never used
// A a = new A(); // CS8036
Diagnostic(ErrorCode.WRN_UnreferencedField, "a").WithArguments("A.a").WithLocation(4, 7));
}
[WorkItem(542356, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/542356")]
[Fact]
public void StaticMemberExplosion()
{
string program = @"
struct A<T>
{
static A<A<T>> x;
}
struct B<T>
{
static A<B<T>> x;
}
struct C<T>
{
static D<T> x;
}
struct D<T>
{
static C<D<T>> x;
}
";
CreateCompilation(program)
.VerifyDiagnostics(
// (14,17): error CS0523: Struct member 'C<T>.x' of type 'D<T>' causes a cycle in the struct layout
// static D<T> x;
Diagnostic(ErrorCode.ERR_StructLayoutCycle, "x").WithArguments("C<T>.x", "D<T>").WithLocation(14, 17),
// (18,20): error CS0523: Struct member 'D<T>.x' of type 'C<D<T>>' causes a cycle in the struct layout
// static C<D<T>> x;
Diagnostic(ErrorCode.ERR_StructLayoutCycle, "x").WithArguments("D<T>.x", "C<D<T>>").WithLocation(18, 20),
// (4,20): error CS0523: Struct member 'A<T>.x' of type 'A<A<T>>' causes a cycle in the struct layout
// static A<A<T>> x;
Diagnostic(ErrorCode.ERR_StructLayoutCycle, "x").WithArguments("A<T>.x", "A<A<T>>").WithLocation(4, 20),
// (9,20): warning CS0169: The field 'B<T>.x' is never used
// static A<B<T>> x;
Diagnostic(ErrorCode.WRN_UnreferencedField, "x").WithArguments("B<T>.x").WithLocation(9, 20),
// (4,20): warning CS0169: The field 'A<T>.x' is never used
// static A<A<T>> x;
Diagnostic(ErrorCode.WRN_UnreferencedField, "x").WithArguments("A<T>.x").WithLocation(4, 20),
// (18,20): warning CS0169: The field 'D<T>.x' is never used
// static C<D<T>> x;
Diagnostic(ErrorCode.WRN_UnreferencedField, "x").WithArguments("D<T>.x").WithLocation(18, 20),
// (14,17): warning CS0169: The field 'C<T>.x' is never used
// static D<T> x;
Diagnostic(ErrorCode.WRN_UnreferencedField, "x").WithArguments("C<T>.x").WithLocation(14, 17)
);
}
[Fact]
public void StaticSequential()
{
string program = @"
partial struct S
{
public static int x;
}
partial struct S
{
public static int y;
}";
CreateCompilation(program)
.VerifyDiagnostics(
// (4,23): warning CS0649: Field 'S.x' is never assigned to, and will always have its default value 0
// public static int x;
Diagnostic(ErrorCode.WRN_UnassignedInternalField, "x").WithArguments("S.x", "0"),
// (9,23): warning CS0649: Field 'S.y' is never assigned to, and will always have its default value 0
// public static int y;
Diagnostic(ErrorCode.WRN_UnassignedInternalField, "y").WithArguments("S.y", "0")
);
}
[WorkItem(542567, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/542567")]
[Fact]
public void ImplicitFieldSequential()
{
string program =
@"partial struct S1
{
public int x;
}
partial struct S1
{
public int y { get; set; }
}
partial struct S2
{
public int x;
}
delegate void D();
partial struct S2
{
public event D y;
}";
CreateCompilation(program)
.VerifyDiagnostics(
// (1,16): warning CS0282: There is no defined ordering between fields in multiple declarations of partial struct 'S1'. To specify an ordering, all instance fields must be in the same declaration.
// partial struct S1
Diagnostic(ErrorCode.WRN_SequentialOnPartialClass, "S1").WithArguments("S1"),
// (11,16): warning CS0282: There is no defined ordering between fields in multiple declarations of partial struct 'S2'. To specify an ordering, all instance fields must be in the same declaration.
// partial struct S2
Diagnostic(ErrorCode.WRN_SequentialOnPartialClass, "S2").WithArguments("S2"),
// (3,16): warning CS0649: Field 'S1.x' is never assigned to, and will always have its default value 0
// public int x;
Diagnostic(ErrorCode.WRN_UnassignedInternalField, "x").WithArguments("S1.x", "0"),
// (13,16): warning CS0649: Field 'S2.x' is never assigned to, and will always have its default value 0
// public int x;
Diagnostic(ErrorCode.WRN_UnassignedInternalField, "x").WithArguments("S2.x", "0"),
// (19,20): warning CS0067: The event 'S2.y' is never used
// public event D y;
Diagnostic(ErrorCode.WRN_UnreferencedEvent, "y").WithArguments("S2.y")
);
}
[Fact]
public void StaticInitializer()
{
string program = @"
public struct A
{
static System.Func<int> d = () => { int j; return j * 9000; };
public static void Main()
{
}
}
";
CreateCompilation(program)
.VerifyDiagnostics(
Diagnostic(ErrorCode.ERR_UseDefViolation, "j").WithArguments("j")
);
}
[Fact]
public void AllPiecesAssigned()
{
string program = @"
struct S
{
public int x, y;
}
class Program
{
public static void Main(string[] args)
{
S s;
s.x = args.Length;
s.y = args.Length;
S t = s;
}
}
";
CreateCompilation(program)
.VerifyDiagnostics(
);
}
[Fact]
public void OnePieceMissing()
{
string program = @"
struct S
{
public int x, y;
}
class Program
{
public static void Main(string[] args)
{
S s;
s.x = args.Length;
S t = s;
}
}
";
CreateCompilation(program)
.VerifyDiagnostics(
// (12,15): error CS0165: Use of unassigned local variable 's'
// S t = s;
Diagnostic(ErrorCode.ERR_UseDefViolation, "s").WithArguments("s"),
// (4,19): warning CS0649: Field 'S.y' is never assigned to, and will always have its default value 0
// public int x, y;
Diagnostic(ErrorCode.WRN_UnassignedInternalField, "y").WithArguments("S.y", "0")
);
}
[Fact]
public void OnePieceOnOnePath()
{
string program = @"
struct S
{
public int x, y;
}
class Program
{
public void F(S s)
{
S s2;
if (s.x == 3)
s2 = s;
else
s2.x = s.x;
int x = s2.x;
}
}
";
CreateCompilation(program)
.VerifyDiagnostics(
// (4,19): warning CS0649: Field 'S.y' is never assigned to, and will always have its default value 0
// public int x, y;
Diagnostic(ErrorCode.WRN_UnassignedInternalField, "y").WithArguments("S.y", "0")
);
}
[Fact]
public void DefaultConstructor()
{
string program = @"
struct S
{
public int x, y;
}
class Program
{
public static void Main(string[] args)
{
S s = new S();
s.x = s.y = s.x;
}
}
";
CreateCompilation(program)
.VerifyDiagnostics(
);
}
[Fact]
public void FieldAssignedInConstructor()
{
string program = @"
struct S
{
int x, y;
S(int x, int y) { this.x = x; this.y = y; }
}";
CreateCompilation(program)
.VerifyDiagnostics(
);
}
[Fact]
public void FieldUnassignedInConstructor()
{
string program = @"
struct S
{
int x, y;
S(int x) { this.x = x; }
}";
CreateCompilation(program, parseOptions: TestOptions.Regular10)
.VerifyDiagnostics(
// (5,5): error CS0171: Field 'S.y' must be fully assigned before control is returned to the caller. Consider updating to language version '11.0' to auto-default the field.
// S(int x) { this.x = x; }
Diagnostic(ErrorCode.ERR_UnassignedThisUnsupportedVersion, "S").WithArguments("S.y", "11.0").WithLocation(5, 5),
// (4,12): warning CS0169: The field 'S.y' is never used
// int x, y;
Diagnostic(ErrorCode.WRN_UnreferencedField, "y").WithArguments("S.y").WithLocation(4, 12)
);
var verifier = CompileAndVerify(program, parseOptions: TestOptions.Regular11);
verifier.VerifyDiagnostics(
// (4,12): warning CS0169: The field 'S.y' is never used
// int x, y;
Diagnostic(ErrorCode.WRN_UnreferencedField, "y").WithArguments("S.y").WithLocation(4, 12));
verifier.VerifyIL("S..ctor", @"
{
// Code size 15 (0xf)
.maxstack 2
IL_0000: ldarg.0
IL_0001: ldc.i4.0
IL_0002: stfld ""int S.y""
IL_0007: ldarg.0
IL_0008: ldarg.1
IL_0009: stfld ""int S.x""
IL_000e: ret
}
");
}
[WorkItem(543429, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/543429")]
[Fact]
public void ConstructorCannotComplete()
{
string program = @"using System;
public struct S
{
int value;
public S(int value)
{
throw new NotImplementedException();
}
}";
CreateCompilation(program).VerifyDiagnostics(
// (4,9): warning CS0169: The field 'S.value' is never used
// int value;
Diagnostic(ErrorCode.WRN_UnreferencedField, "value").WithArguments("S.value")
);
}
[Fact]
public void AutoPropInitialization1()
{
string program = @"
struct Program
{
public int X { get; private set; }
public Program(int x)
{
}
public static void Main(string[] args)
{
}
}";
CreateCompilation(program, parseOptions: TestOptions.Regular10)
.VerifyDiagnostics(
// (5,12): error CS0843: Auto-implemented property 'Program.X' must be fully assigned before control is returned to the caller. Consider updating to language version '11.0' to auto-default the property.
// public Program(int x)
Diagnostic(ErrorCode.ERR_UnassignedThisAutoPropertyUnsupportedVersion, "Program").WithArguments("Program.X", "11.0").WithLocation(5, 12));
var verifier = CompileAndVerify(program, parseOptions: TestOptions.Regular11);
verifier.VerifyDiagnostics();
verifier.VerifyIL("Program..ctor", @"
{
// Code size 8 (0x8)
.maxstack 2
IL_0000: ldarg.0
IL_0001: ldc.i4.0
IL_0002: stfld ""int Program.<X>k__BackingField""
IL_0007: ret
}");
}
[Fact]
public void AutoPropInitialization2()
{
var text = @"struct S
{
public int P { get; set; } = 1;
internal static long Q { get; } = 10;
public decimal R { get; } = 300;
public S(int i) {}
}";
var comp = CreateCompilation(text, parseOptions: TestOptions.Regular9);
comp.VerifyDiagnostics(
// (3,16): error CS8773: Feature 'struct field initializers' is not available in C# 9.0. Please use language version 10.0 or greater.
// public int P { get; set; } = 1;
Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, "P").WithArguments("struct field initializers", "10.0").WithLocation(3, 16),
// (5,20): error CS8773: Feature 'struct field initializers' is not available in C# 9.0. Please use language version 10.0 or greater.
// public decimal R { get; } = 300;
Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, "R").WithArguments("struct field initializers", "10.0").WithLocation(5, 20));
comp = CreateCompilation(text);
comp.VerifyDiagnostics();
}
[Fact]
public void AutoPropInitialization3()
{
var text = @"struct S
{
public int P { get; private set; }
internal static long Q { get; } = 10;
public decimal R { get; } = 300;
public S(int p)
{
P = p;
}
}";
var comp = CreateCompilation(text, parseOptions: TestOptions.Regular9);
comp.VerifyDiagnostics(
// (5,20): error CS8773: Feature 'struct field initializers' is not available in C# 9.0. Please use language version 10.0 or greater.
// public decimal R { get; } = 300;
Diagnostic(ErrorCode.ERR_FeatureNotAvailableInVersion9, "R").WithArguments("struct field initializers", "10.0").WithLocation(5, 20));
comp = CreateCompilation(text);
comp.VerifyDiagnostics();
}
[Fact]
public void AutoPropInitialization4()
{
var text = @"
struct Program
{
struct S1
{
public int i;
public int ii { get; }
}
S1 x { get; }
S1 x2 { get; }
public Program(int dummy)
{
x.i = 1;
System.Console.WriteLine(x2.ii);
}
public void Goo()
{
}
static void Main(string[] args)
{
}
}";
var comp = CreateCompilation(text, parseOptions: TestOptions.Regular10);
comp.VerifyDiagnostics(
// (16,9): error CS1612: Cannot modify the return value of 'Program.x' because it is not a variable
// x.i = 1;
Diagnostic(ErrorCode.ERR_ReturnNotLValue, "x").WithArguments("Program.x").WithLocation(16, 9),
// (16,9): error CS9015: Use of possibly unassigned field 'i'. Consider updating to language version '11.0' to auto-default the field.
// x.i = 1;
Diagnostic(ErrorCode.ERR_UseDefViolationFieldUnsupportedVersion, "x.i").WithArguments("i", "11.0").WithLocation(16, 9),
// (17,34): error CS9014: Use of possibly unassigned auto-implemented property 'x2'. Consider updating to language version '11.0' to auto-default the property.
// System.Console.WriteLine(x2.ii);
Diagnostic(ErrorCode.ERR_UseDefViolationPropertyUnsupportedVersion, "x2").WithArguments("x2", "11.0").WithLocation(17, 34),
// (14,12): error CS0843: Auto-implemented property 'Program.x' must be fully assigned before control is returned to the caller. Consider updating to language version '11.0' to auto-default the property.
// public Program(int dummy)
Diagnostic(ErrorCode.ERR_UnassignedThisAutoPropertyUnsupportedVersion, "Program").WithArguments("Program.x", "11.0").WithLocation(14, 12),
// (14,12): error CS0843: Auto-implemented property 'Program.x2' must be fully assigned before control is returned to the caller. Consider updating to language version '11.0' to auto-default the property.
// public Program(int dummy)
Diagnostic(ErrorCode.ERR_UnassignedThisAutoPropertyUnsupportedVersion, "Program").WithArguments("Program.x2", "11.0").WithLocation(14, 12));
comp = CreateCompilation(text, parseOptions: TestOptions.Regular11);
comp.VerifyDiagnostics(
// (16,9): error CS1612: Cannot modify the return value of 'Program.x' because it is not a variable
// x.i = 1;
Diagnostic(ErrorCode.ERR_ReturnNotLValue, "x").WithArguments("Program.x").WithLocation(16, 9));
}
[Fact]
public void AutoPropInitialization5()
{
var text = @"
struct Program
{
struct S1
{
public int i;
public int ii { get; }
}
S1 x { get; set;}
S1 x2 { get; set;}
public Program(int dummy)
{
x.i = 1;
System.Console.WriteLine(x2.ii);
}
public void Goo()
{
}
static void Main(string[] args)
{
}
}";
var comp = CreateCompilation(text, parseOptions: TestOptions.Regular10);
comp.VerifyDiagnostics(
// (16,9): error CS1612: Cannot modify the return value of 'Program.x' because it is not a variable
// x.i = 1;
Diagnostic(ErrorCode.ERR_ReturnNotLValue, "x").WithArguments("Program.x").WithLocation(16, 9),
// (16,9): error CS9015: Use of possibly unassigned field 'i'. Consider updating to language version '11.0' to auto-default the field.
// x.i = 1;
Diagnostic(ErrorCode.ERR_UseDefViolationFieldUnsupportedVersion, "x.i").WithArguments("i", "11.0").WithLocation(16, 9),
// (17,34): error CS9014: Use of possibly unassigned auto-implemented property 'x2'. Consider updating to language version '11.0' to auto-default the property.
// System.Console.WriteLine(x2.ii);
Diagnostic(ErrorCode.ERR_UseDefViolationPropertyUnsupportedVersion, "x2").WithArguments("x2", "11.0").WithLocation(17, 34),
// (14,12): error CS0843: Auto-implemented property 'Program.x' must be fully assigned before control is returned to the caller. Consider updating to language version '11.0' to auto-default the property.
// public Program(int dummy)
Diagnostic(ErrorCode.ERR_UnassignedThisAutoPropertyUnsupportedVersion, "Program").WithArguments("Program.x", "11.0").WithLocation(14, 12),
// (14,12): error CS0843: Auto-implemented property 'Program.x2' must be fully assigned before control is returned to the caller. Consider updating to language version '11.0' to auto-default the property.
// public Program(int dummy)
Diagnostic(ErrorCode.ERR_UnassignedThisAutoPropertyUnsupportedVersion, "Program").WithArguments("Program.x2", "11.0").WithLocation(14, 12));
comp = CreateCompilation(text, options: TestOptions.DebugDll.WithSpecificDiagnosticOptions(ReportStructInitializationWarnings), parseOptions: TestOptions.Regular11);
comp.VerifyDiagnostics(
// (14,12): warning CS9020: Control is returned to caller before auto-implemented property 'Program.x' is explicitly assigned, causing a preceding implicit assignment of 'default'.
// public Program(int dummy)
Diagnostic(ErrorCode.WRN_UnassignedThisAutoPropertySupportedVersion, "Program").WithArguments("Program.x").WithLocation(14, 12),
// (14,12): warning CS9020: Control is returned to caller before auto-implemented property 'Program.x2' is explicitly assigned, causing a preceding implicit assignment of 'default'.
// public Program(int dummy)
Diagnostic(ErrorCode.WRN_UnassignedThisAutoPropertySupportedVersion, "Program").WithArguments("Program.x2").WithLocation(14, 12),
// (16,9): error CS1612: Cannot modify the return value of 'Program.x' because it is not a variable
// x.i = 1;
Diagnostic(ErrorCode.ERR_ReturnNotLValue, "x").WithArguments("Program.x").WithLocation(16, 9),
// (16,9): warning CS9018: Field 'i' is read before being explicitly assigned, causing a preceding implicit assignment of 'default'.
// x.i = 1;
Diagnostic(ErrorCode.WRN_UseDefViolationFieldSupportedVersion, "x.i").WithArguments("i").WithLocation(16, 9),
// (17,34): warning CS9017: Auto-implemented property 'x2' is read before being explicitly assigned, causing a preceding implicit assignment of 'default'.
// System.Console.WriteLine(x2.ii);
Diagnostic(ErrorCode.WRN_UseDefViolationPropertySupportedVersion, "x2").WithArguments("x2").WithLocation(17, 34));
comp = CreateCompilation(text, parseOptions: TestOptions.Regular11);
comp.VerifyDiagnostics(
// (16,9): error CS1612: Cannot modify the return value of 'Program.x' because it is not a variable
// x.i = 1;
Diagnostic(ErrorCode.ERR_ReturnNotLValue, "x").WithArguments("Program.x").WithLocation(16, 9));
}
[Fact]
public void AutoPropInitialization6()
{
var text = @"
struct Program
{
struct S1
{
public int i;
public int ii { get; }
}
S1 x { get; set;}
S1 x2 { get;}
public Program(int dummy)
{
x = new S1();
x.i += 1;
x2 = new S1();
x2.i += 1;
}
public void Goo()
{
}
static void Main(string[] args)
{
}
}";
var comp = CreateCompilation(text);
comp.VerifyDiagnostics(
// (17,9): error CS1612: Cannot modify the return value of 'Program.x' because it is not a variable
// x.i += 1;
Diagnostic(ErrorCode.ERR_ReturnNotLValue, "x").WithArguments("Program.x").WithLocation(17, 9),
// (20,9): error CS1612: Cannot modify the return value of 'Program.x2' because it is not a variable
// x2.i += 1;
Diagnostic(ErrorCode.ERR_ReturnNotLValue, "x2").WithArguments("Program.x2").WithLocation(20, 9)
);
}
[Fact]
public void AutoPropInitialization7()
{
var text = @"
struct Program
{
struct S1
{
public int i;
public int ii { get; }
}
S1 x { get; set;}
S1 x2 { get;}
public Program(int dummy)
{
this = default(Program);
System.Action a = () =>
{
this.x = new S1();
};
System.Action a2 = () =>
{
this.x2 = new S1();
};
}
public void Goo()
{
}
static void Main(string[] args)
{
}
}";
var comp = CreateCompilation(text);
comp.VerifyDiagnostics(
// (20,13): error CS1673: Anonymous methods, lambda expressions, query expressions, and local functions inside structs cannot access instance members of 'this'. Consider copying 'this' to a local variable outside the anonymous method, lambda expression, query expression, or local function and using the local instead.
// this.x = new S1();
Diagnostic(ErrorCode.ERR_ThisStructNotInAnonMeth, "this").WithLocation(20, 13),
// (25,13): error CS1673: Anonymous methods, lambda expressions, query expressions, and local functions inside structs cannot access instance members of 'this'. Consider copying 'this' to a local variable outside the anonymous method, lambda expression, query expression, or local function and using the local instead.
// this.x2 = new S1();
Diagnostic(ErrorCode.ERR_ThisStructNotInAnonMeth, "this").WithLocation(25, 13),
// (6,20): warning CS0649: Field 'Program.S1.i' is never assigned to, and will always have its default value 0
// public int i;
Diagnostic(ErrorCode.WRN_UnassignedInternalField, "i").WithArguments("Program.S1.i", "0").WithLocation(6, 20)
);
}
[Fact]
public void AutoPropInitialization7c()
{
var text = @"
class Program
{
struct S1
{
public int i;
public int ii { get; }
}
S1 x { get; set;}
S1 x2 { get;}
public Program()
{
System.Action a = () =>
{
this.x = new S1();
};
System.Action a2 = () =>
{
this.x2 = new S1();
};
}
public void Goo()
{
}
static void Main(string[] args)
{
}
}";
var comp = CreateCompilation(text);
comp.VerifyDiagnostics(
// (23,13): error CS0200: Property or indexer 'Program.x2' cannot be assigned to -- it is read only
// this.x2 = new S1();
Diagnostic(ErrorCode.ERR_AssgReadonlyProp, "this.x2").WithArguments("Program.x2").WithLocation(23, 13),
// (6,20): warning CS0649: Field 'Program.S1.i' is never assigned to, and will always have its default value 0
// public int i;
Diagnostic(ErrorCode.WRN_UnassignedInternalField, "i").WithArguments("Program.S1.i", "0").WithLocation(6, 20)
);
}
[Fact]
public void AutoPropInitialization8()
{
var text = @"
struct Program
{
struct S1
{
public int i;
public int ii { get; }
}
S1 x { get; set;}
S1 x2 { get;}
public Program(int arg)
: this()
{
x2 = x;
}
public void Goo()
{
}
static void Main(string[] args)
{
}
}";
var comp = CreateCompilation(text);
comp.VerifyDiagnostics(
// (6,20): warning CS0649: Field 'Program.S1.i' is never assigned to, and will always have its default value 0
// public int i;
Diagnostic(ErrorCode.WRN_UnassignedInternalField, "i").WithArguments("Program.S1.i", "0").WithLocation(6, 20)
);
}
[Fact]
public void AutoPropInitialization9()
{
var text = @"
struct Program
{
struct S1
{
}
S1 x { get; set;}
S1 x2 { get;}
public Program(int arg)
{
x2 = x;
}
public void Goo()
{
}
static void Main(string[] args)
{
}
}";
var comp = CreateCompilation(text);
// no errors since S1 is empty
comp.VerifyDiagnostics(
);
}
[Fact]
public void AutoPropInitialization10()
{
var text = @"
struct Program
{
public struct S1
{
public int x;
}
S1 x1 { get; set;}
S1 x2 { get;}
S1 x3;
public Program(int arg)
{
Goo(out x1);
Goo(ref x1);
Goo(out x2);
Goo(ref x2);
Goo(out x3);
Goo(ref x3);
}
public static void Goo(out S1 s)
{
s = default(S1);
}
public static void Goo1(ref S1 s)
{
s = default(S1);
}
static void Main(string[] args)
{
}
}";
var comp = CreateCompilation(text, parseOptions: TestOptions.Regular10);
comp.VerifyDiagnostics(
// (15,17): error CS0206: A property or indexer may not be passed as an out or ref parameter
// Goo(out x1);
Diagnostic(ErrorCode.ERR_RefProperty, "x1").WithLocation(15, 17),
// (16,17): error CS0206: A property or indexer may not be passed as an out or ref parameter
// Goo(ref x1);
Diagnostic(ErrorCode.ERR_RefProperty, "x1").WithLocation(16, 17),
// (17,17): error CS0206: A property or indexer may not be passed as an out or ref parameter
// Goo(out x2);
Diagnostic(ErrorCode.ERR_RefProperty, "x2").WithLocation(17, 17),
// (18,17): error CS0206: A property or indexer may not be passed as an out or ref parameter
// Goo(ref x2);
Diagnostic(ErrorCode.ERR_RefProperty, "x2").WithLocation(18, 17),
// (20,17): error CS1620: Argument 1 must be passed with the 'out' keyword
// Goo(ref x3);
Diagnostic(ErrorCode.ERR_BadArgRef, "x3").WithArguments("1", "out").WithLocation(20, 17),
// (15,17): error CS9014: Use of possibly unassigned auto-implemented property 'x1'. Consider updating to language version '11.0' to auto-default the property.
// Goo(out x1);
Diagnostic(ErrorCode.ERR_UseDefViolationPropertyUnsupportedVersion, "x1").WithArguments("x1", "11.0").WithLocation(15, 17),
// (16,9): error CS0188: The 'this' object cannot be used before all of its fields have been assigned. Consider updating to language version '11.0' to auto-default the unassigned fields.
// Goo(ref x1);
Diagnostic(ErrorCode.ERR_UseDefViolationThisUnsupportedVersion, "Goo").WithArguments("11.0").WithLocation(16, 9),
// (17,17): error CS9014: Use of possibly unassigned auto-implemented property 'x2'. Consider updating to language version '11.0' to auto-default the property.
// Goo(out x2);
Diagnostic(ErrorCode.ERR_UseDefViolationPropertyUnsupportedVersion, "x2").WithArguments("x2", "11.0").WithLocation(17, 17),
// (6,20): warning CS0649: Field 'Program.S1.x' is never assigned to, and will always have its default value 0
// public int x;
Diagnostic(ErrorCode.WRN_UnassignedInternalField, "x").WithArguments("Program.S1.x", "0").WithLocation(6, 20)
);
comp = CreateCompilation(text, parseOptions: TestOptions.Regular11);
comp.VerifyDiagnostics(
// (15,17): error CS0206: A property or indexer may not be passed as an out or ref parameter
// Goo(out x1);
Diagnostic(ErrorCode.ERR_RefProperty, "x1").WithLocation(15, 17),
// (16,17): error CS0206: A property or indexer may not be passed as an out or ref parameter
// Goo(ref x1);
Diagnostic(ErrorCode.ERR_RefProperty, "x1").WithLocation(16, 17),
// (17,17): error CS0206: A property or indexer may not be passed as an out or ref parameter
// Goo(out x2);
Diagnostic(ErrorCode.ERR_RefProperty, "x2").WithLocation(17, 17),
// (18,17): error CS0206: A property or indexer may not be passed as an out or ref parameter
// Goo(ref x2);
Diagnostic(ErrorCode.ERR_RefProperty, "x2").WithLocation(18, 17),
// (20,17): error CS1620: Argument 1 must be passed with the 'out' keyword
// Goo(ref x3);
Diagnostic(ErrorCode.ERR_BadArgRef, "x3").WithArguments("1", "out").WithLocation(20, 17),
// (6,20): warning CS0649: Field 'Program.S1.x' is never assigned to, and will always have its default value 0
// public int x;
Diagnostic(ErrorCode.WRN_UnassignedInternalField, "x").WithArguments("Program.S1.x", "0").WithLocation(6, 20)
);
}
[Fact]
public void EmptyStructAlwaysAssigned()
{
string program = @"
struct S
{
static S M()
{
S s;
return s;
}
}
";
CreateCompilation(program)
.VerifyDiagnostics(
);
}
[Fact]
public void DeeplyEmptyStructAlwaysAssigned()
{
string program = @"
struct S
{
static S M()
{
S s;
return s;
}
}
struct T
{
S s1, s2, s3;
static T M()
{
T t;
return t;
}
}";
CreateCompilation(program)
.VerifyDiagnostics(
// (13,15): warning CS0169: The field 'T.s3' is never used
// S s1, s2, s3;
Diagnostic(ErrorCode.WRN_UnreferencedField, "s3").WithArguments("T.s3").WithLocation(13, 15),
// (13,11): warning CS0169: The field 'T.s2' is never used
// S s1, s2, s3;
Diagnostic(ErrorCode.WRN_UnreferencedField, "s2").WithArguments("T.s2").WithLocation(13, 11),
// (13,7): warning CS0169: The field 'T.s1' is never used
// S s1, s2, s3;
Diagnostic(ErrorCode.WRN_UnreferencedField, "s1").WithArguments("T.s1").WithLocation(13, 7)
);
}
[WorkItem(543466, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/543466")]
[Fact]
public void UnreferencedFieldWarningsMissingInEmit()
{
var comp = CreateCompilation(@"
public class Class1
{
int field1;
}");
var bindingDiags = comp.GetDiagnostics().ToArray();
Assert.Equal(1, bindingDiags.Length);
Assert.Equal(ErrorCode.WRN_UnreferencedField, (ErrorCode)bindingDiags[0].Code);
var emitDiags = comp.Emit(new System.IO.MemoryStream()).Diagnostics.ToArray();
Assert.Equal(bindingDiags.Length, emitDiags.Length);
Assert.Equal(bindingDiags[0], emitDiags[0]);
}
[Fact]
public void DefiniteAssignGenericStruct()
{
string program = @"
using System;
struct C<T>
{
public int num;
public int Goo1()
{
return this.num;
}
}
class Test
{
static void Main(string[] args)
{
C<object> c;
c.num = 1;
bool verify = c.Goo1() == 1;
Console.WriteLine(verify);
}
}
";
CreateCompilation(program)
.VerifyDiagnostics(
);
}
[WorkItem(540896, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/540896")]
[WorkItem(541268, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/541268")]
[Fact]
public void ChainToStructDefaultConstructor()
{
string program = @"
using System;
namespace Roslyn.Compilers.CSharp
{
class DecimalRewriter
{
private DecimalRewriter() { }
private struct DecimalParts
{
public DecimalParts(decimal value)
: this()
{
int[] bits = Decimal.GetBits(value);
Low = bits[0];
}
public int Low { get; private set; }
}
}
}
";
CreateCompilation(program)
.VerifyDiagnostics(
);
}
[WorkItem(541298, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/541298")]
[WorkItem(541298, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/541298")]
[Fact]
public void SetStaticPropertyOnStruct()
{
string source = @"
struct S
{
public static int p { get; internal set; }
}
class C
{
public static void Main()
{
S.p = 10;
}
}
";
CreateCompilation(source).VerifyDiagnostics();
}
[Fact]
public void UsingPart()
{
string program = @"
struct S
{
public int x;
}
class Program
{
public static void Main(string[] args)
{
S s = new S();
s.x = 12;
}
}";
CreateCompilation(program).VerifyDiagnostics();
}
[Fact]
public void ReferencingCycledStructures()
{
string program = @"
public struct A
{
public static void Main()
{
S1 s1 = new S1();
S2 s2 = new S2();
s2.fld = new S3();
s2.fld.fld.fld.fld = new S2();
}
}
";
var c = CreateCompilation(program, new[] { TestReferences.SymbolsTests.CycledStructs });
c.VerifyDiagnostics(
// (6,12): warning CS0219: The variable 's1' is assigned but its value is never used
// S1 s1 = new S1();
Diagnostic(ErrorCode.WRN_UnreferencedVarAssg, "s1").WithArguments("s1"));
}
[Fact]
public void BigStruct()
{
string source = @"
struct S<T>
{
T a, b, c, d, e, f, g, h;
S(T t)
{
a = b = c = d = e = f = g = h = t;
}
static void M()
{
S<S<S<S<S<S<S<S<int>>>>>>>> x;
x.a.a.a.a.a.a.a.a = 12;
x.a.a.a.a.a.a.a.b = x.a.a.a.a.a.a.a.a;
}
}";
CreateCompilation(source).VerifyDiagnostics();
}
[Fact]
[WorkItem(542901, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/542901")]
public void DataFlowForStructFieldAssignment()
{
string program = @"struct S
{
public float X;
public float Y;
public float Z;
void M()
{
if (3 < 3.4)
{
S s;
if (s.X < 3)
{
s = GetS();
s.Z = 10f;
}
else
{
}
}
else
{
}
}
private static S GetS()
{
return new S();
}
}
";
CreateCompilation(program).VerifyDiagnostics(
// (12,17): error CS0170: Use of possibly unassigned field 'X'
// if (s.X < 3)
Diagnostic(ErrorCode.ERR_UseDefViolationField, "s.X").WithArguments("X"),
// (3,18): warning CS0649: Field 'S.X' is never assigned to, and will always have its default value 0
// public float X;
Diagnostic(ErrorCode.WRN_UnassignedInternalField, "X").WithArguments("S.X", "0"),
// (4,18): warning CS0649: Field 'S.Y' is never assigned to, and will always have its default value 0
// public float Y;
Diagnostic(ErrorCode.WRN_UnassignedInternalField, "Y").WithArguments("S.Y", "0")
);
}
[Fact]
[WorkItem(2470, "https://github.com/dotnet/roslyn/issues/2470")]
public void NoFieldNeverAssignedWarning()
{
string program = @"
using System.Threading.Tasks;
internal struct TaskEvent<T>
{
private TaskCompletionSource<T> _tcs;
public Task<T> Task
{
get
{
if (_tcs == null)
_tcs = new TaskCompletionSource<T>();
return _tcs.Task;
}
}
public void Invoke(T result)
{
if (_tcs != null)
{
TaskCompletionSource<T> localTcs = _tcs;
_tcs = null;
localTcs.SetResult(result);
}
}
}
public class OperationExecutor
{
private TaskEvent<float?> _nextValueEvent; // Field is never assigned warning
// Start some async operation
public Task<bool> StartOperation()
{
return null;
}
// Get progress or data during async operation
public Task<float?> WaitNextValue()
{
return _nextValueEvent.Task;
}
// Called externally
internal void OnNextValue(float? value)
{
_nextValueEvent.Invoke(value);
}
}
";
CreateCompilationWithMscorlib461(program).VerifyEmitDiagnostics();
}
#endregion
[Fact, WorkItem(545347, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/545347")]
public void FieldInAbstractClass_UnusedField()
{
var text = @"
abstract class AbstractType
{
public int Kind;
}";
CreateCompilation(text).VerifyDiagnostics(
// (4,16): warning CS0649: Field 'AbstractType.Kind' is never assigned to, and will always have its default value 0
// public int Kind;
Diagnostic(ErrorCode.WRN_UnassignedInternalField, "Kind").WithArguments("AbstractType.Kind", "0").WithLocation(4, 16));
}
[Fact, WorkItem(545347, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/545347")]
public void FieldInAbstractClass_FieldUsedInChildType()
{
var text = @"
abstract class AbstractType
{
public int Kind;
}
class ChildType : AbstractType
{
public ChildType()
{
this.Kind = 1;
}
}
";
CreateCompilation(text).VerifyDiagnostics();
}
[Fact]
[WorkItem(545642, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/545642")]
public void InitializerAndConstructorWithOutParameter()
{
string program =
@"class Program
{
private int field = Goo();
static int Goo() { return 12; }
public Program(out int x)
{
x = 13;
}
}";
CreateCompilation(program).VerifyDiagnostics();
}
[Fact]
[WorkItem(545875, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/545875")]
public void TestSuppressUnreferencedVarAssgOnIntPtr()
{
var source = @"
using System;
public class Test
{
public static void Main()
{
IntPtr i1 = (IntPtr)0;
IntPtr i2 = (IntPtr)10L;
UIntPtr ui1 = (UIntPtr)0;
UIntPtr ui2 = (UIntPtr)10L;
IntPtr z = IntPtr.Zero;
int ip1 = (int)z;
long lp1 = (long)z;
UIntPtr uz = UIntPtr.Zero;
int ip2 = (int)uz;
long lp2 = (long)uz;
}
}";
CreateCompilation(source).VerifyDiagnostics();
}
[Fact]
[WorkItem(546183, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/546183")]
public void TestUnassignedStructFieldsInPInvokePassByRefCase()
{
var source = @"
using System;
using System.Runtime.InteropServices;
namespace ManagedDebuggingAssistants
{
internal class DebugMonitor
{
internal DebugMonitor()
{
SECURITY_ATTRIBUTES attributes = new SECURITY_ATTRIBUTES();
SECURITY_DESCRIPTOR descriptor = new SECURITY_DESCRIPTOR();
IntPtr pDescriptor = IntPtr.Zero;
IntPtr pAttributes = IntPtr.Zero;
attributes.nLength = Marshal.SizeOf(attributes);
attributes.bInheritHandle = true;
attributes.lpSecurityDescriptor = pDescriptor;
if (!InitializeSecurityDescriptor(ref descriptor, 1 /*SECURITY_DESCRIPTOR_REVISION*/))
throw new ApplicationException(""InitializeSecurityDescriptor failed: "" + Marshal.GetLastWin32Error());
if (!SetSecurityDescriptorDacl(ref descriptor, true, IntPtr.Zero, false))
throw new ApplicationException(""SetSecurityDescriptorDacl failed: "" + Marshal.GetLastWin32Error());
Marshal.StructureToPtr(descriptor, pDescriptor, false);
Marshal.StructureToPtr(attributes, pAttributes, false);
}
#region Interop definitions
private struct SECURITY_DESCRIPTOR
{
internal byte Revision;
internal byte Sbz1;
internal short Control;
internal IntPtr Owner;
internal IntPtr Group;
internal IntPtr Sacl;
internal IntPtr Dacl;
}
private struct SECURITY_ATTRIBUTES
{
internal int nLength;
internal IntPtr lpSecurityDescriptor;
// disable csharp compiler warning #0414: field assigned unused value
#pragma warning disable 0414
internal bool bInheritHandle;
#pragma warning restore 0414
}
[DllImport(""advapi32.dll"", SetLastError = true)]
private static extern bool InitializeSecurityDescriptor([In] ref SECURITY_DESCRIPTOR pSecurityDescriptor, int dwRevision);
[DllImport(""advapi32.dll"", SetLastError = true)]
private static extern bool SetSecurityDescriptorDacl([In] ref SECURITY_DESCRIPTOR pSecurityDescriptor, bool bDaclPresent, IntPtr pDacl, bool bDaclDefaulted);
#endregion
}
}";
CreateCompilation(source).VerifyDiagnostics();
}
[WorkItem(546673, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/546673")]
[Fact]
public void TestBreakInsideNonLocalScopeBinder()
{
var source = @"
public class C
{
public static void Main()
{
while (true)
{
unchecked
{
break;
}
}
switch(0)
{
case 0:
unchecked
{
break;
}
}
while (true)
{
unsafe
{
break;
}
}
switch(0)
{
case 0:
unsafe
{
break;
}
}
bool flag = false;
while (!flag)
{
flag = true;
unchecked
{
continue;
}
}
flag = false;
while (!flag)
{
flag = true;
unsafe
{
continue;
}
}
}
}";
CompileAndVerify(source, options: TestOptions.UnsafeReleaseExe, expectedOutput: "");
}
[WorkItem(611904, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/611904")]
[Fact]
public void LabelAtTopLevelInsideLambda()
{
var source = @"
class Program
{
delegate T SomeDelegate<T>(out bool f);
static void Main(string[] args)
{
Test((out bool f) =>
{
if (1.ToString() != null)
goto l2;
f = true;
l1:
if (1.ToString() != null)
return 123; // <==== ERROR EXPECTED HERE
f = true;
if (1.ToString() != null)
return 456;
l2:
goto l1;
});
}
static void Test<T>(SomeDelegate<T> f)
{
}
}";
CSharpCompilation comp = CreateCompilationWithMscorlib40AndSystemCore(source);
comp.VerifyDiagnostics(
// (17,17): error CS0177: The out parameter 'f' must be assigned to before control leaves the current method
// return 123; // <==== ERROR EXPECTED HERE
Diagnostic(ErrorCode.ERR_ParamUnassigned, "return 123;").WithArguments("f")
);
}
[WorkItem(633927, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/633927")]
[Fact]
public void Xyzzy()
{
var source =
@"class C
{
struct S
{
int x;
S(dynamic y)
{
Goo(y, null);
}
}
static void Goo(int y)
{
}
}";
CSharpCompilation comp = CreateCompilationWithMscorlib40AndSystemCore(source, parseOptions: TestOptions.Regular10);
comp.VerifyDiagnostics(
// (8,13): error CS1501: No overload for method 'Goo' takes 2 arguments
// Goo(y, null);
Diagnostic(ErrorCode.ERR_BadArgCount, "Goo").WithArguments("Goo", "2").WithLocation(8, 13),
// (6,9): error CS0171: Field 'C.S.x' must be fully assigned before control is returned to the caller. Consider updating to language version '11.0' to auto-default the field.
// S(dynamic y)
Diagnostic(ErrorCode.ERR_UnassignedThisUnsupportedVersion, "S").WithArguments("C.S.x", "11.0").WithLocation(6, 9),
// (5,13): warning CS0169: The field 'C.S.x' is never used
// int x;
Diagnostic(ErrorCode.WRN_UnreferencedField, "x").WithArguments("C.S.x").WithLocation(5, 13)
);
comp = CreateCompilationWithMscorlib40AndSystemCore(source, parseOptions: TestOptions.Regular11);
comp.VerifyDiagnostics(
// (8,13): error CS1501: No overload for method 'Goo' takes 2 arguments
// Goo(y, null);
Diagnostic(ErrorCode.ERR_BadArgCount, "Goo").WithArguments("Goo", "2").WithLocation(8, 13),
// (5,13): warning CS0169: The field 'C.S.x' is never used
// int x;
Diagnostic(ErrorCode.WRN_UnreferencedField, "x").WithArguments("C.S.x").WithLocation(5, 13)
);
}
[WorkItem(667368, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/667368")]
[Fact]
public void RegressionTest667368()
{
var source =
@"using System.Collections.Generic;
namespace ConsoleApplication1
{
internal class Class1
{
Dictionary<string, int> _dict = new Dictionary<string, int>();
public Class1()
{
}
public int? GetCode(dynamic value)
{
int val;
if (value != null && _dict.TryGetValue(value, out val))
return val;
return null;
}
}
}";
CSharpCompilation comp = CreateCompilationWithMscorlib40AndSystemCore(source);
comp.VerifyDiagnostics(
// (17,24): error CS0165: Use of unassigned local variable 'val'
// return val;
Diagnostic(ErrorCode.ERR_UseDefViolation, "val").WithArguments("val")
);
}
[WorkItem(690921, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/690921")]
[Fact]
public void RegressionTest690921()
{
var source =
@"using System.Collections.Generic;
namespace ConsoleApplication1
{
internal class Class1
{
Dictionary<string, int> _dict = new Dictionary<string, int>();
public Class1()
{
}
public static string GetOutBoxItemId(string itemName, string uniqueIdKey, string listUrl, Dictionary<string, dynamic> myList = null, bool useDefaultCredentials = false)
{
string uniqueId = null;
dynamic myItemName;
if (myList != null && myList.TryGetValue(""DisplayName"", out myItemName) && myItemName == itemName)
{
}
return uniqueId;
}
public static void Main() { }
}
}
";
CSharpCompilation comp = CreateCompilationWithMscorlib40AndSystemCore(source);
comp.VerifyDiagnostics();
}
[WorkItem(715338, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/715338")]
[Fact]
public void RegressionTest715338()
{
var source =
@"using System;
using System.Collections.Generic;
static class Program
{
static void Add(this IList<int> source, string key, int value) { }
static void View(Action<string, int> adder) { }
static readonly IList<int> myInts = null;
static void Main()
{
View(myInts.Add);
}
}";
CSharpCompilation comp = CreateCompilationWithMscorlib40AndSystemCore(source);
comp.VerifyDiagnostics();
}
[WorkItem(808567, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/808567")]
[Fact]
public void RegressionTest808567()
{
var source =
@"class Base
{
public Base(out int x, System.Func<int> u)
{
x = 0;
}
}
class Derived2 : Base
{
Derived2(out int p1)
: base(out p1, ()=>p1)
{
}
}";
CSharpCompilation comp = CreateCompilationWithMscorlib40AndSystemCore(source);
comp.VerifyDiagnostics(
// (11,28): error CS1628: Cannot use ref or out parameter 'p1' inside an anonymous method, lambda expression, or query expression
// : base(out p1, ()=>p1)
Diagnostic(ErrorCode.ERR_AnonDelegateCantUse, "p1").WithArguments("p1"),
// (11,20): error CS0269: Use of unassigned out parameter 'p1'
// : base(out p1, ()=>p1)
Diagnostic(ErrorCode.ERR_UseDefViolationOut, "p1").WithArguments("p1")
);
}
[WorkItem(949324, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/949324")]
[Fact]
public void RegressionTest949324()
{
var source =
@"struct Derived
{
Derived(int x) { }
Derived(long x) : this(p2) // error CS0188: The 'this' object cannot be used before all of its fields are assigned to
{
this = new Derived();
}
private int x;
}";
CSharpCompilation comp = CreateCompilationWithMscorlib40AndSystemCore(source, parseOptions: TestOptions.Regular10);
comp.VerifyDiagnostics(
// (3,5): error CS0171: Field 'Derived.x' must be fully assigned before control is returned to the caller. Consider updating to language version '11.0' to auto-default the field.
// Derived(int x) { }
Diagnostic(ErrorCode.ERR_UnassignedThisUnsupportedVersion, "Derived").WithArguments("Derived.x", "11.0").WithLocation(3, 5),
// (4,28): error CS0103: The name 'p2' does not exist in the current context
// Derived(long x) : this(p2) // error CS0188: The 'this' object cannot be used before all of its fields are assigned to
Diagnostic(ErrorCode.ERR_NameNotInContext, "p2").WithArguments("p2").WithLocation(4, 28),
// (8,17): warning CS0169: The field 'Derived.x' is never used
// private int x;
Diagnostic(ErrorCode.WRN_UnreferencedField, "x").WithArguments("Derived.x").WithLocation(8, 17)
);
comp = CreateCompilationWithMscorlib40AndSystemCore(source, parseOptions: TestOptions.Regular11);
comp.VerifyDiagnostics(
// (4,28): error CS0103: The name 'p2' does not exist in the current context
// Derived(long x) : this(p2) // error CS0188: The 'this' object cannot be used before all of its fields are assigned to
Diagnostic(ErrorCode.ERR_NameNotInContext, "p2").WithArguments("p2").WithLocation(4, 28),
// (8,17): warning CS0169: The field 'Derived.x' is never used
// private int x;
Diagnostic(ErrorCode.WRN_UnreferencedField, "x").WithArguments("Derived.x").WithLocation(8, 17)
);
}
[WorkItem(612, "https://github.com/dotnet/roslyn/issues/612")]
[Fact]
public void CascadedUnreachableCode()
{
var source =
@"class Program
{
public static void Main()
{
string k;
switch (1)
{
case 1:
}
string s = k;
}
}";
CSharpCompilation comp = CreateCompilation(source);
comp.VerifyDiagnostics(
// (8,9): error CS8070: Control cannot fall out of switch from final case label ('case 1:')
// case 1:
Diagnostic(ErrorCode.ERR_SwitchFallOut, "case 1:").WithArguments("case 1:").WithLocation(8, 9),
// (10,20): error CS0165: Use of unassigned local variable 'k'
// string s = k;
Diagnostic(ErrorCode.ERR_UseDefViolation, "k").WithArguments("k").WithLocation(10, 20)
);
}
[WorkItem(9581, "https://github.com/dotnet/roslyn/issues/9581")]
[Fact]
public void UsingSelfAssignment()
{
var source =
@"class Program
{
static void Main()
{
using (System.IDisposable x = x)
{
}
}
}";
CSharpCompilation comp = CreateCompilation(source);
comp.VerifyDiagnostics(
// (5,39): error CS0165: Use of unassigned local variable 'x'
// using (System.IDisposable x = x)
Diagnostic(ErrorCode.ERR_UseDefViolation, "x").WithArguments("x").WithLocation(5, 39)
);
}
[Fact]
public void UsingAssignment()
{
var source =
@"class Program
{
static void Main()
{
using (System.IDisposable x = null)
{
System.Console.WriteLine(x.ToString());
}
using (System.IDisposable x = null, y = x)
{
System.Console.WriteLine(y.ToString());
}
}
}";
CSharpCompilation comp = CreateCompilation(source);
comp.VerifyDiagnostics(
);
}
[Fact]
public void RangeDefiniteAssignmentOrder()
{
CreateCompilationWithIndexAndRange(@"
class C
{
void M()
{
int x;
var r = (x=0)..(x+1);
int y;
r = (y+1)..(y=0);
}
}").VerifyDiagnostics(
// (9,14): error CS0165: Use of unassigned local variable 'y'
// r = (y+1)..(y=0);
Diagnostic(ErrorCode.ERR_UseDefViolation, "y").WithArguments("y").WithLocation(9, 14));
}
[Fact]
public void FieldAssignedInLambdaOnly()
{
var source =
@"using System;
struct S
{
private object F;
private object G;
public S(object x, object y)
{
Action a = () => { F = x; };
G = y;
}
}";
var comp = CreateCompilation(source, parseOptions: TestOptions.Regular10);
comp.VerifyDiagnostics(
// (6,12): error CS0171: Field 'S.F' must be fully assigned before control is returned to the caller. Consider updating to language version '11.0' to auto-default the field.
// public S(object x, object y)
Diagnostic(ErrorCode.ERR_UnassignedThisUnsupportedVersion, "S").WithArguments("S.F", "11.0").WithLocation(6, 12),
// (8,28): error CS1673: Anonymous methods, lambda expressions, query expressions, and local functions inside structs cannot access instance members of 'this'. Consider copying 'this' to a local variable outside the anonymous method, lambda expression, query expression, or local function and using the local instead.
// Action a = () => { F = x; };
Diagnostic(ErrorCode.ERR_ThisStructNotInAnonMeth, "F").WithLocation(8, 28));
comp = CreateCompilation(source, parseOptions: TestOptions.Regular11);
comp.VerifyDiagnostics(
// (8,28): error CS1673: Anonymous methods, lambda expressions, query expressions, and local functions inside structs cannot access instance members of 'this'. Consider copying 'this' to a local variable outside the anonymous method, lambda expression, query expression, or local function and using the local instead.
// Action a = () => { F = x; };
Diagnostic(ErrorCode.ERR_ThisStructNotInAnonMeth, "F").WithLocation(8, 28));
}
[Fact]
public void FieldAssignedInLocalFunctionOnly()
{
var source =
@"struct S
{
private object F;
private object G;
public S(object x, object y)
{
void f() { F = x; }
G = y;
}
}";
var comp = CreateCompilation(source, parseOptions: TestOptions.Regular10);
comp.VerifyDiagnostics(
// (5,12): error CS0171: Field 'S.F' must be fully assigned before control is returned to the caller. Consider updating to language version '11.0' to auto-default the field.
// public S(object x, object y)
Diagnostic(ErrorCode.ERR_UnassignedThisUnsupportedVersion, "S").WithArguments("S.F", "11.0").WithLocation(5, 12),
// (7,14): warning CS8321: The local function 'f' is declared but never used
// void f() { F = x; }
Diagnostic(ErrorCode.WRN_UnreferencedLocalFunction, "f").WithArguments("f").WithLocation(7, 14),
// (7,20): error CS1673: Anonymous methods, lambda expressions, query expressions, and local functions inside structs cannot access instance members of 'this'. Consider copying 'this' to a local variable outside the anonymous method, lambda expression, query expression, or local function and using the local instead.
// void f() { F = x; }
Diagnostic(ErrorCode.ERR_ThisStructNotInAnonMeth, "F").WithLocation(7, 20));
comp = CreateCompilation(source, parseOptions: TestOptions.Regular11);
comp.VerifyDiagnostics(
// (7,14): warning CS8321: The local function 'f' is declared but never used
// void f() { F = x; }
Diagnostic(ErrorCode.WRN_UnreferencedLocalFunction, "f").WithArguments("f").WithLocation(7, 14),
// (7,20): error CS1673: Anonymous methods, lambda expressions, query expressions, and local functions inside structs cannot access instance members of 'this'. Consider copying 'this' to a local variable outside the anonymous method, lambda expression, query expression, or local function and using the local instead.
// void f() { F = x; }
Diagnostic(ErrorCode.ERR_ThisStructNotInAnonMeth, "F").WithLocation(7, 20));
}
[Fact]
[WorkItem(1243877, "https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1243877")]
public void WorkItem1243877()
{
string program = @"
static class C
{
static void Main()
{
Test(out var x, x);
}
static void Test(out Empty x, object y) => throw null;
}
struct Empty
{
}
";
CreateCompilation(program).VerifyDiagnostics(
// (6,25): error CS8196: Reference to an implicitly-typed out variable 'x' is not permitted in the same argument list.
// Test(out var x, x);
Diagnostic(ErrorCode.ERR_ImplicitlyTypedOutVariableUsedInTheSameArgumentList, "x").WithArguments("x").WithLocation(6, 25)
);
}
}
}
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