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Extensions: allow more CREFs #80114

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Merged
merged 2 commits into from
Sep 7, 2025
Merged

Extensions: allow more CREFs #80114

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8ec786e
Extensions: allow more CREFs
jcouv Aug 28, 2025
965b0f1
Address feedback
jcouv Sep 5, 2025
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35 changes: 25 additions & 10 deletions src/Compilers/CSharp/Portable/Binder/Binder_Crefs.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@
// 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;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Diagnostics;
Expand Down Expand Up @@ -224,12 +225,6 @@ private ImmutableArray<Symbol> BindExtensionMemberCref(ExtensionMemberCrefSyntax
{
CheckFeatureAvailability(syntax, MessageID.IDS_FeatureExtensions, diagnostics);

if (containerOpt is not NamedTypeSymbol namedContainer)
{
ambiguityWinner = null;
return ImmutableArray<Symbol>.Empty;
}

int arity = 0;
TypeArgumentListSyntax? typeArgumentListSyntax = null;
CrefParameterListSyntax? parameters = null;
Expand All @@ -256,7 +251,7 @@ private ImmutableArray<Symbol> BindExtensionMemberCref(ExtensionMemberCrefSyntax

TypeArgumentListSyntax? extensionTypeArguments = syntax.TypeArgumentList;
int extensionArity = extensionTypeArguments?.Arguments.Count ?? 0;
ImmutableArray<Symbol> sortedSymbols = computeSortedAndFilteredCrefExtensionMembers(namedContainer, memberName, extensionArity, arity, extensionTypeArguments, diagnostics, syntax);
ImmutableArray<Symbol> sortedSymbols = computeSortedAndFilteredCrefExtensionMembers(containerOpt, memberName, extensionArity, arity, extensionTypeArguments, diagnostics, syntax);

if (sortedSymbols.IsDefaultOrEmpty)
{
Expand All @@ -268,7 +263,7 @@ private ImmutableArray<Symbol> BindExtensionMemberCref(ExtensionMemberCrefSyntax

return ProcessCrefMemberLookupResults(sortedSymbols, arity, syntax, typeArgumentListSyntax, parameters, out ambiguityWinner, diagnostics);

ImmutableArray<Symbol> computeSortedAndFilteredCrefExtensionMembers(NamedTypeSymbol container, string name, int extensionArity, int arity, TypeArgumentListSyntax? extensionTypeArguments, BindingDiagnosticBag diagnostics, ExtensionMemberCrefSyntax syntax)
ImmutableArray<Symbol> computeSortedAndFilteredCrefExtensionMembers(NamespaceOrTypeSymbol? containerOpt, string name, int extensionArity, int arity, TypeArgumentListSyntax? extensionTypeArguments, BindingDiagnosticBag diagnostics, ExtensionMemberCrefSyntax syntax)
{
Debug.Assert(name is not null);

Expand All @@ -295,9 +290,12 @@ ImmutableArray<Symbol> computeSortedAndFilteredCrefExtensionMembers(NamedTypeSym
CompoundUseSiteInfo<AssemblySymbol> useSiteInfo = this.GetNewCompoundUseSiteInfo(diagnostics);
ArrayBuilder<Symbol>? sortedSymbolsBuilder = null;

foreach (var nested in container.GetTypeMembers())
foreach (var nested in candidateTypes(containerOpt))
{
if (!nested.IsExtension || nested.Arity != extensionArity || nested.ExtensionParameter is null)
if (!nested.IsExtension
|| nested.Arity != extensionArity
|| nested.ExtensionParameter is null
|| nested is not { ContainingType: { ContainingType: null } }) // only consider extension blocks in top-level types
{
continue;
}
Expand Down Expand Up @@ -364,6 +362,23 @@ ImmutableArray<Symbol> computeSortedAndFilteredCrefExtensionMembers(NamedTypeSym
}

return sortedSymbolsBuilder.ToImmutableAndFree();

ImmutableArray<NamedTypeSymbol> candidateTypes(NamespaceOrTypeSymbol? containerOpt)
{
if (containerOpt is NamedTypeSymbol namedType)
{
return namedType.GetTypeMembers("");
}

NamedTypeSymbol? containingType = ContainingType;
if (containingType is null)
{
return [];
}

NamedTypeSymbol? enclosingType = containingType.IsExtension ? containingType.ContainingType : containingType;
return enclosingType?.GetTypeMembers("") ?? [];
}
}
}

Expand Down
1 change: 1 addition & 0 deletions src/Compilers/CSharp/Portable/Binder/WithCrefTypeParametersBinder.cs
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Expand Up @@ -63,6 +63,7 @@ private MultiDictionary<string, TypeParameterSymbol> CreateTypeParameterMap()
case SyntaxKind.IndexerMemberCref:
case SyntaxKind.OperatorMemberCref:
case SyntaxKind.ConversionOperatorMemberCref:
case SyntaxKind.ExtensionMemberCref:
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@AlekseyTs AlekseyTs Sep 5, 2025 •
edited
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case SyntaxKind.ExtensionMemberCref:

Is this change related to "Addresses part of #78967 ("We want unqualified CREF to work within the context of enclosing static type cref="extension(int).M"")"? If not, consider adjusting PR description accordingly. #Closed

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@AlekseyTs AlekseyTs Sep 5, 2025 •
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case SyntaxKind.ExtensionMemberCref:

Is there a test covering method type parameters for this case? #Closed

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Added Cref_66

{
AddTypeParameters((MemberCrefSyntax)_crefSyntax, map);
break;
Expand Down
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