/// <summary>
/// Infer return type. If `nullableState` is non-null, nullability is also inferred and `NullableWalker.Analyze`
/// uses that state to set the inferred nullability of variables in the enclosing scope. `conversions` is
/// only needed when nullability is inferred.
/// </summary>
public TypeWithAnnotations GetInferredReturnType(ConversionsBase conversions, NullableWalker.VariableState nullableState, ref HashSet <DiagnosticInfo> useSiteDiagnostics)
{
if (!InferredReturnType.UseSiteDiagnostics.IsEmpty)
{
if (useSiteDiagnostics == null)
{
useSiteDiagnostics = new HashSet <DiagnosticInfo>();
}
foreach (var info in InferredReturnType.UseSiteDiagnostics)
{
useSiteDiagnostics.Add(info);
}
}
if (nullableState == null)
{
return(InferredReturnType.TypeWithAnnotations);
}
else
{
Debug.Assert(conversions != null);
// Diagnostics from NullableWalker.Analyze can be dropped here since Analyze
// will be called again from NullableWalker.ApplyConversion when the
// BoundLambda is converted to an anonymous function.
// https://github.com/dotnet/roslyn/issues/31752: Can we avoid generating extra
// diagnostics? And is this exponential when there are nested lambdas?
var returnTypes = ArrayBuilder <(BoundReturnStatement, TypeWithAnnotations)> .GetInstance();
var diagnostics = DiagnosticBag.GetInstance();
var delegateType = Type.GetDelegateType();
var compilation = Binder.Compilation;
NullableWalker.Analyze(compilation,
lambda: this,
(Conversions)conversions,
diagnostics,
delegateInvokeMethod: delegateType?.DelegateInvokeMethod,
initialState: nullableState,
analyzedNullabilityMapOpt: null,
updatedMethodSymbolMapOpt: null,
snapshotBuilderOpt: null,
returnTypes);
diagnostics.Free();
var inferredReturnType = InferReturnType(returnTypes, node: this, compilation, conversions, delegateType, Symbol.IsAsync);
returnTypes.Free();
return(inferredReturnType.TypeWithAnnotations);
}
}
public TypeSymbolWithAnnotations GetInferredReturnType(ref HashSet <DiagnosticInfo> useSiteDiagnostics, NullableWalker.VariableState nullableState = null)
{
if (!InferredReturnType.UseSiteDiagnostics.IsEmpty)
{
if (useSiteDiagnostics == null)
{
useSiteDiagnostics = new HashSet <DiagnosticInfo>();
}
foreach (var info in InferredReturnType.UseSiteDiagnostics)
{
useSiteDiagnostics.Add(info);
}
}
if (nullableState == null)
{
return(InferredReturnType.Type);
}
else
{
var returnTypes = ArrayBuilder <(RefKind, TypeSymbolWithAnnotations)> .GetInstance();
// Diagnostics from NullableWalker.Analyze can be dropped here since Analyze
// will be called again from NullableWalker.ApplyConversion when the
// BoundLambda is converted to an anonymous function.
// https://github.com/dotnet/roslyn/issues/29617 Can we avoid generating extra
// diagnostics? And is this exponential when there are nested lambdas?
var diagnostics = DiagnosticBag.GetInstance();
var delegateType = Type.GetDelegateType();
var compilation = Binder.Compilation;
var conversions = (Conversions)Binder.Conversions.WithNullability(includeNullability: true);
NullableWalker.Analyze(compilation, lambda: this, diagnostics, delegateInvokeMethod: delegateType?.DelegateInvokeMethod, returnTypes: returnTypes, initialState: nullableState);
diagnostics.Free();
var inferredReturnType = InferReturnType(returnTypes, compilation, conversions, delegateType, Symbol.IsAsync);
returnTypes.Free();
return(inferredReturnType.Type);
}
}
/// <summary>
/// Verify the type and nullability inferred by NullabilityWalker of all expressions in the source
/// that are followed by specific annotations. Annotations are of the form /*T:type*/.
/// </summary>
internal static void VerifyTypes(this CSharpCompilation compilation, SyntaxTree tree = null)
{
if (tree == null)
{
foreach (var syntaxTree in compilation.SyntaxTrees)
{
VerifyTypes(compilation, syntaxTree);
}
return;
}
var root = tree.GetRoot();
var allAnnotations = getAnnotations();
if (allAnnotations.IsEmpty)
{
return;
}
var model = compilation.GetSemanticModel(tree);
var annotationsByMethod = allAnnotations.GroupBy(annotation => annotation.Expression.Ancestors().OfType <BaseMethodDeclarationSyntax>().First()).ToArray();
foreach (var annotations in annotationsByMethod)
{
var method = (MethodSymbol)model.GetDeclaredSymbol(annotations.Key);
var diagnostics = DiagnosticBag.GetInstance();
var block = MethodCompiler.BindMethodBody(method, new TypeCompilationState(method.ContainingType, compilation, null), diagnostics);
var dictionary = new Dictionary <SyntaxNode, TypeSymbolWithAnnotations>();
NullableWalker.Analyze(
compilation,
method,
block,
diagnostics,
callbackOpt: (BoundExpression expr, TypeSymbolWithAnnotations exprType) => dictionary[expr.Syntax] = exprType);
diagnostics.Free();
var expectedTypes = annotations.SelectAsArray(annotation => annotation.Text);
var actualTypes = annotations.SelectAsArray(annotation => toDisplayString(annotation.Expression));
// Consider reporting the correct source with annotations on mismatch.
AssertEx.Equal(expectedTypes, actualTypes, message: method.ToTestDisplayString());
foreach (var entry in dictionary.Values.Where(v => !v.IsNull))
{
// Result types cannot have nested types that are unspeakables
Assert.Null(entry.VisitType(typeOpt: null,
typeWithAnnotationsPredicateOpt: (tswa, a, b) => !tswa.Equals(entry, TypeCompareKind.ConsiderEverything) && !tswa.NullableAnnotation.IsSpeakable(),
typePredicateOpt: (ts, _, b) => false, arg: (object)null, canDigThroughNullable: true));
}
string toDisplayString(SyntaxNode syntaxOpt)
{
return((syntaxOpt != null) && dictionary.TryGetValue(syntaxOpt, out var type) ?
(type.IsNull ? "<null>" : type.ToDisplayString(TypeSymbolWithAnnotations.TestDisplayFormat)) :
null);
}
}
ImmutableArray <(ExpressionSyntax Expression, string Text)> getAnnotations()
{
var builder = ArrayBuilder <(ExpressionSyntax, string)> .GetInstance();
foreach (var token in root.DescendantTokens())
{
foreach (var trivia in token.TrailingTrivia)
{
if (trivia.Kind() == SyntaxKind.MultiLineCommentTrivia)
{
var text = trivia.ToFullString();
const string prefix = "/*T:";
const string suffix = "*/";
if (text.StartsWith(prefix) && text.EndsWith(suffix))
{
var expr = getEnclosingExpression(token);
Assert.True(expr != null, $"VerifyTypes could not find a matching expression for annotation '{text}'.");
var content = text.Substring(prefix.Length, text.Length - prefix.Length - suffix.Length);
builder.Add((expr, content));
}
}
}
}
return(builder.ToImmutableAndFree());
}
ExpressionSyntax getEnclosingExpression(SyntaxToken token)
{
var node = token.Parent;
while (true)
{
var expr = asExpression(node);
if (expr != null)
{
return(expr);
}
if (node == root)
{
break;
}
node = node.Parent;
}
return(null);
}
ExpressionSyntax asExpression(SyntaxNode node)
{
var expr = node as ExpressionSyntax;
if (expr == null)
{
return(null);
}
switch (expr.Kind())
{
case SyntaxKind.ParenthesizedExpression:
return(((ParenthesizedExpressionSyntax)expr).Expression);
case SyntaxKind.IdentifierName:
if (expr.Parent is MemberAccessExpressionSyntax memberAccess && memberAccess.Name == expr)
{
return(memberAccess);
}
break;
}
return(expr);
}
}