Let concurrent and read-only dictionaries call DeepClone() without a cast - #84
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matt-edmondson merged 1 commit intoSep 27, 2026
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…cast ConcurrentDictionary<,> and ReadOnlyDictionary<,> implement both IDictionary<,> and IReadOnlyDictionary<,>, so dictionary.DeepClone() was an ambiguous call (CS0121) for them. Add concrete overloads, as Dictionary<,> and SortedDictionary<,> already have. The ConcurrentDictionary overload keeps the key comparer on .NET 6 and later, where the type exposes it. Remove the cast workarounds from the tests. Fixes #81 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01KaXGMeYeXB1J32kSrLGhgJ
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September 27, 2026 15:10
This was referenced Sep 28, 2026
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Fixes #81
What was wrong
ConcurrentDictionary<,>andReadOnlyDictionary<,>implement bothIDictionary<,>andIReadOnlyDictionary<,>, so callingDeepClone()on either one failed to compile with CS0121 (ambiguous call). #79 already fixed this forDictionary<,>andSortedDictionary<,>. These two types were still left.Change
DeepClone(this ConcurrentDictionary<,>)overload that returns aConcurrentDictionary<,>. On .NET 6 and later it keeps the source's key comparer. The .NET Standard targets can't readConcurrentDictionary.Comparer, so on those the clone uses the default comparer. The XML doc says so.DeepClone(this ReadOnlyDictionary<,>)overload that returns a newReadOnlyDictionary<,>wrapping a deep-cloned dictionary.DeepCloneTests.cs("Cast to IDictionary to resolve ambiguity") andSpecializedCollectionTests.cs("explicit cast to IDictionary to resolve ambiguity").Tests
ConcurrentDictionary_DeepClone_ShouldCreateIndependentCopynow callsoriginal.DeepClone()directly.ConcurrentDictionary_DeepClone_ShouldKeepComparerandReadOnlyDictionaryWrapper_DeepClone_ShouldCreateIndependentCopy.dotnet testpasses 44/44.Not in scope
ImmutableDictionary<,>andImmutableSortedDictionary<,>also implement both interfaces, so they would hit the same ambiguity. Cloning them throughIDictionary<,>would also callAddon an immutable type. They need their own design, so they are left for a separate issue. #83 (comparer loss through theIDictionarypath forSortedListand others) is also separate.🤖 Generated with Claude Code
https://claude.ai/code/session_01KaXGMeYeXB1J32kSrLGhgJ
Generated by Claude Code