/// <summary>
/// Analyzes if type information is obvious to the reader by simply looking at the assignment expression.
/// </summary>
/// <remarks>
/// <paramref name="typeInDeclaration"/> accepts null, to be able to cater to codegen features
/// that are about to generate a local declaration and do not have this information to pass in.
/// Things (like analyzers) that do have a local declaration already, should pass this in.
/// </remarks>
public static bool IsTypeApparentInAssignmentExpression(
TypeStylePreference stylePreferences,
ExpressionSyntax initializerExpression,
SemanticModel semanticModel,
CancellationToken cancellationToken,
ITypeSymbol typeInDeclaration = null)
{
// default(type)
if (initializerExpression.IsKind(SyntaxKind.DefaultExpression))
{
return true;
}
// literals, use var if options allow usage here.
if (initializerExpression.IsAnyLiteralExpression())
{
return stylePreferences.HasFlag(TypeStylePreference.ImplicitTypeForIntrinsicTypes);
}
// constructor invocations cases:
// = new type();
if (initializerExpression.IsKind(SyntaxKind.ObjectCreationExpression) &&
!initializerExpression.IsKind(SyntaxKind.AnonymousObjectCreationExpression))
{
return true;
}
// explicit conversion cases:
// (type)expr, expr is type, expr as type
if (initializerExpression.IsKind(SyntaxKind.CastExpression) ||
initializerExpression.IsKind(SyntaxKind.IsExpression) ||
initializerExpression.IsKind(SyntaxKind.AsExpression))
{
return true;
}
// other Conversion cases:
// a. conversion with helpers like: int.Parse methods
// b. types that implement IConvertible and then invoking .ToType()
// c. System.Convert.Totype()
var memberName = GetRightmostInvocationExpression(initializerExpression).GetRightmostName();
if (memberName == null)
{
return false;
}
var methodSymbol = semanticModel.GetSymbolInfo(memberName, cancellationToken).Symbol as IMethodSymbol;
if (methodSymbol == null)
{
return false;
}
if (memberName.IsRightSideOfDot())
{
var containingTypeName = memberName.GetLeftSideOfDot();
return IsPossibleCreationOrConversionMethod(methodSymbol, typeInDeclaration, semanticModel, containingTypeName, cancellationToken);
}
return false;
}
/// <summary>
/// Returns true if type information could be gleaned by simply looking at the given statement.
/// This typically means that the type name occurs in right hand side of an assignment.
/// </summary>
private bool IsTypeApparentInDeclaration(VariableDeclarationSyntax variableDeclaration, SemanticModel semanticModel, TypeStylePreference stylePreferences, CancellationToken cancellationToken)
{
var initializer = variableDeclaration.Variables.Single().Initializer;
var initializerExpression = GetInitializerExpression(initializer);
var declaredTypeSymbol = semanticModel.GetTypeInfo(variableDeclaration.Type, cancellationToken).Type;
return TypeStyleHelper.IsTypeApparentInAssignmentExpression(stylePreferences, initializerExpression, semanticModel,cancellationToken, declaredTypeSymbol);
}
private static bool IsImplicitStylePreferred(
TypeStylePreference stylePreferences, bool isBuiltInTypeContext, bool isTypeApparentContext)
{
return(isBuiltInTypeContext
? stylePreferences.HasFlag(TypeStylePreference.ImplicitTypeForIntrinsicTypes)
: isTypeApparentContext
? stylePreferences.HasFlag(TypeStylePreference.ImplicitTypeWhereApparent)
: stylePreferences.HasFlag(TypeStylePreference.ImplicitTypeWherePossible));
}
private static bool IsImplicitStylePreferred(TypeStylePreference stylePreferences,
bool isBuiltInTypeContext,
bool isTypeApparentContext)
{
return isBuiltInTypeContext
? stylePreferences.HasFlag(TypeStylePreference.ImplicitTypeForIntrinsicTypes)
: isTypeApparentContext
? stylePreferences.HasFlag(TypeStylePreference.ImplicitTypeWhereApparent)
: stylePreferences.HasFlag(TypeStylePreference.ImplicitTypeWherePossible);
}
/// <summary>
/// Returns true if type information could be gleaned by simply looking at the given statement.
/// This typically means that the type name occurs in right hand side of an assignment.
/// </summary>
private bool IsTypeApparentInDeclaration(VariableDeclarationSyntax variableDeclaration, SemanticModel semanticModel, TypeStylePreference stylePreferences, CancellationToken cancellationToken)
{
var initializer = variableDeclaration.Variables.Single().Initializer;
var initializerExpression = GetInitializerExpression(initializer.Value);
var declaredTypeSymbol = semanticModel.GetTypeInfo(variableDeclaration.Type, cancellationToken).Type;
return(TypeStyleHelper.IsTypeApparentInAssignmentExpression(stylePreferences, initializerExpression, semanticModel, cancellationToken, declaredTypeSymbol));
}
/// <summary>
/// Returns true if type information could be gleaned by simply looking at the given statement.
/// This typically means that the type name occurs in right hand side of an assignment.
/// </summary>
private bool IsTypeApparentInDeclaration(VariableDeclarationSyntax variableDeclaration, SemanticModel semanticModel, TypeStylePreference stylePreferences, CancellationToken cancellationToken)
{
if (variableDeclaration.Variables.Count != 1)
{
return(false);
}
var initializer = variableDeclaration.Variables[0].Initializer;
if (initializer == null)
{
return(false);
}
var initializerExpression = CSharpUseImplicitTypeHelper.GetInitializerExpression(initializer.Value);
var declaredTypeSymbol = semanticModel.GetTypeInfo(variableDeclaration.Type, cancellationToken).Type;
return(TypeStyleHelper.IsTypeApparentInAssignmentExpression(stylePreferences, initializerExpression, semanticModel, cancellationToken, declaredTypeSymbol));
}
/// <summary>
/// Analyzes if type information is obvious to the reader by simply looking at the assignment expression.
/// </summary>
/// <remarks>
/// <paramref name="typeInDeclaration"/> accepts null, to be able to cater to codegen features
/// that are about to generate a local declaration and do not have this information to pass in.
/// Things (like analyzers) that do have a local declaration already, should pass this in.
/// </remarks>
public static bool IsTypeApparentInAssignmentExpression(
TypeStylePreference stylePreferences,
ExpressionSyntax initializerExpression,
SemanticModel semanticModel,
CancellationToken cancellationToken,
ITypeSymbol typeInDeclaration = null)
{
// default(type)
if (initializerExpression.IsKind(SyntaxKind.DefaultExpression))
{
return(true);
}
// literals, use var if options allow usage here.
if (initializerExpression.IsAnyLiteralExpression())
{
return(stylePreferences.HasFlag(TypeStylePreference.ImplicitTypeForIntrinsicTypes));
}
// constructor invocations cases:
// = new type();
if (initializerExpression.IsKind(SyntaxKind.ObjectCreationExpression) &&
!initializerExpression.IsKind(SyntaxKind.AnonymousObjectCreationExpression))
{
return(true);
}
// explicit conversion cases:
// (type)expr, expr is type, expr as type
if (initializerExpression.IsKind(SyntaxKind.CastExpression) ||
initializerExpression.IsKind(SyntaxKind.IsExpression) ||
initializerExpression.IsKind(SyntaxKind.AsExpression))
{
return(true);
}
// other Conversion cases:
// a. conversion with helpers like: int.Parse methods
// b. types that implement IConvertible and then invoking .ToType()
// c. System.Convert.Totype()
var memberName = GetRightmostInvocationExpression(initializerExpression).GetRightmostName();
if (memberName == null)
{
return(false);
}
var methodSymbol = semanticModel.GetSymbolInfo(memberName, cancellationToken).Symbol as IMethodSymbol;
if (methodSymbol == null)
{
return(false);
}
if (memberName.IsRightSideOfDot())
{
var containingTypeName = memberName.GetLeftSideOfDot();
return(IsPossibleCreationOrConversionMethod(methodSymbol, typeInDeclaration, semanticModel, containingTypeName, cancellationToken));
}
return(false);
}
