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Merged
jinujoseph merged 2 commits into from
Mar 23, 2018
Merged

"Deconstruct variable declaration" should not introduce errors #25282

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6ddcd0e
Only offering UseDeconstruction when type of value used to initialize…
Neme12 Mar 6, 2018
ba07025
Adding tests with tuple conversions
Neme12 Mar 6, 2018
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195 changes: 195 additions & 0 deletions src/EditorFeatures/CSharpTest/UseDeconstruction/UseDeconstructionTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -465,6 +465,201 @@ void M()
}

(string name, int age) GetPerson() => default;
}");
}

[WorkItem(25260, "https://github.com/dotnet/roslyn/issues/25260")]
[Fact, Trait(Traits.Feature, Traits.Features.CodeActionsUseDeconstruction)]
public async Task TestNotWithDefaultLiteralInitializer()
{
await TestMissingInRegularAndScriptAsync(
@"class C
{
void M()
{
(string name, int age) [|person|] = default;
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@jcouv jcouv Mar 17, 2018

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Filed #25559

Console.WriteLine(person.name + "" "" + person.age);
}
}");
}

[Fact, Trait(Traits.Feature, Traits.Features.CodeActionsUseDeconstruction)]
public async Task TestWithDefaultExpressionInitializer()
{
await TestInRegularAndScriptAsync(
@"class C
{
void M()
{
(string name, int age) [|person|] = default((string, int));
Console.WriteLine(person.name + "" "" + person.age);
}
}",
@"class C
{
void M()
{
(string name, int age) = default((string, int));
Console.WriteLine(name + "" "" + age);
}
}");
}

[Fact, Trait(Traits.Feature, Traits.Features.CodeActionsUseDeconstruction)]
public async Task TestNotWithImplicitConversionFromNonTuple()
{
await TestMissingInRegularAndScriptAsync(
@"class C
{
class Person
{
public static implicit operator (string, int)(Person person) => default;
}

void M()
{
(string name, int age) [|person|] = new Person();
Console.WriteLine(person.name + "" "" + person.age);
}
}");
}

[Fact, Trait(Traits.Feature, Traits.Features.CodeActionsUseDeconstruction)]
public async Task TestWithExplicitImplicitConversionFromNonTuple()
{
await TestInRegularAndScriptAsync(
@"class C
{
class Person
{
public static implicit operator (string, int)(Person person) => default;
}

void M()
{
(string name, int age) [|person|] = ((string, int))new Person();
Console.WriteLine(person.name + "" "" + person.age);
}
}",
@"class C
{
class Person
{
public static implicit operator (string, int)(Person person) => default;
}

void M()
{
(string name, int age) = ((string, int))new Person();
Console.WriteLine(name + "" "" + age);
}
}");
}

[Fact, Trait(Traits.Feature, Traits.Features.CodeActionsUseDeconstruction)]
public async Task TestNotWithImplicitConversionFromNonTupleInForEach()
{
await TestMissingInRegularAndScriptAsync(
@"class C
{
class Person
{
public static implicit operator (string, int)(Person person) => default;
}

void M()
{
foreach ((string name, int age) [|person|] in new Person[] { })
Console.WriteLine(person.name + "" "" + person.age);
}
}");
}

[Fact, Trait(Traits.Feature, Traits.Features.CodeActionsUseDeconstruction)]
public async Task TestWithExplicitImplicitConversionFromNonTupleInForEach()
{
await TestInRegularAndScriptAsync(
@"using System.Linq;
class C
{
class Person
{
public static implicit operator (string, int)(Person person) => default;
}

void M()
{
foreach ((string name, int age) [|person|] in new Person[] { }.Cast<(string, int)>())
Console.WriteLine(person.name + "" "" + person.age);
}
}",
@"using System.Linq;
class C
{
class Person
{
public static implicit operator (string, int)(Person person) => default;
}

void M()
{
foreach ((string name, int age) in new Person[] { }.Cast<(string, int)>())
Console.WriteLine(name + "" "" + age);
}
}");
}

[Fact, Trait(Traits.Feature, Traits.Features.CodeActionsUseDeconstruction)]
public async Task TestWithImplicitTupleConversion()
{
await TestInRegularAndScriptAsync(
@"class C
{
void M()
{
(object name, double age) [|person|] = GetPerson();
Console.WriteLine(person.name + "" "" + person.age);
}

(string name, int age) GetPerson() => default;
}",
@"class C
{
void M()
{
(object name, double age) = GetPerson();
Console.WriteLine(name + "" "" + age);
}

(string name, int age) GetPerson() => default;
}");
}

[Fact, Trait(Traits.Feature, Traits.Features.CodeActionsUseDeconstruction)]
public async Task TestWithImplicitTupleConversionInForEach()
{
await TestInRegularAndScriptAsync(
@"using System.Collections.Generic;
class C
{
void M()
{
foreach ((object name, double age) [|person|] in GetPeople())
Console.WriteLine(person.name + "" "" + person.age);
}

IEnumerable<(string name, int age)> GetPeople() => default;
}",
@"using System.Collections.Generic;
class C
{
void M()
{
foreach ((object name, double age) in GetPeople())
Console.WriteLine(name + "" "" + age);
}

IEnumerable<(string name, int age)> GetPeople() => default;
}");
}
}
Expand Down
13 changes: 8 additions & 5 deletions src/Features/CSharp/Portable/UseDeconstruction/CSharpUseDeconstructionDiagnosticAnalyzer.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -125,11 +125,11 @@ public static bool TryAnalyzeVariableDeclaration(
}

var local = (ILocalSymbol)semanticModel.GetDeclaredSymbol(declarator, cancellationToken);
var expressionType = semanticModel.GetTypeInfo(declarator.Initializer.Value, cancellationToken).Type;

return TryAnalyze(
semanticModel, local, variableDeclaration.Type,
declarator.Identifier, variableDeclaration.Parent.Parent,
out tupleType, out memberAccessExpressions, cancellationToken);
semanticModel, local, variableDeclaration.Type, declarator.Identifier, expressionType,
variableDeclaration.Parent.Parent, out tupleType, out memberAccessExpressions, cancellationToken);
}

public static bool TryAnalyzeForEachStatement(
Expand All @@ -140,9 +140,10 @@ public static bool TryAnalyzeForEachStatement(
CancellationToken cancellationToken)
{
var local = semanticModel.GetDeclaredSymbol(forEachStatement, cancellationToken);
var elementType = semanticModel.GetForEachStatementInfo(forEachStatement).ElementType;

return TryAnalyze(
semanticModel, local, forEachStatement.Type, forEachStatement.Identifier,
semanticModel, local, forEachStatement.Type, forEachStatement.Identifier, elementType,
forEachStatement, out tupleType, out memberAccessExpressions, cancellationToken);
}

Expand All @@ -151,6 +152,7 @@ private static bool TryAnalyze(
ILocalSymbol local,
TypeSyntax typeNode,
SyntaxToken identifier,
ITypeSymbol initializerType,
SyntaxNode searchScope,
out INamedTypeSymbol tupleType,
out ImmutableArray<MemberAccessExpressionSyntax> memberAccessExpressions,
Expand All @@ -170,7 +172,8 @@ private static bool TryAnalyze(
}

var type = semanticModel.GetTypeInfo(typeNode, cancellationToken).Type;
if (type == null || !type.IsTupleType)
if (type == null || !type.IsTupleType ||
initializerType == null || !initializerType.IsTupleType)
{
return false;
}
Expand Down