What's wrong
ContiguousMap<TKey, TValue>.TryGetValue(TKey key, out TValue value) (Containers/ContiguousMap.cs ~line 438) sets value = default! on a miss, but its out parameter has no [MaybeNullWhen(false)]. Its siblings InsertionOrderMap and OrderedMap do carry the attribute (under #if NET5_0_OR_GREATER), and CompatibilitySuppressions.xml lists theirs but not this one.
Repro (verified: compiled and ran against current main, <Nullable>enable</Nullable>)
var m = new ContiguousMap<string, string>();
if (!m.TryGetValue("x", out string v))
Console.WriteLine(v.Length); // no warning; NullReferenceException at runtimeThe same code with InsertionOrderMap<string, string> gets a CS8600 warning, as it should.
Why it matters
Nullable flow analysis is wrong for one of the three map types. A caller that switches from InsertionOrderMap to ContiguousMap for performance silently loses the null-safety check. The code also doesn't match IDictionary<TKey, TValue>.TryGetValue, which is annotated [MaybeNullWhen(false)].
Suggested fix
Copy the pattern from InsertionOrderMap.TryGetValue:
public bool TryGetValue(TKey key,
#if NET5_0_OR_GREATER
[MaybeNullWhen(false)]
#endif
out TValue value)
Then add the matching entry to CompatibilitySuppressions.xml, the same way the other two maps did.
Acceptance criteria
- The repro produces a nullable warning on NET5+ targets.
- Package validation passes.
What's wrong
ContiguousMap<TKey, TValue>.TryGetValue(TKey key, out TValue value)(Containers/ContiguousMap.cs~line 438) setsvalue = default!on a miss, but itsoutparameter has no[MaybeNullWhen(false)]. Its siblingsInsertionOrderMapandOrderedMapdo carry the attribute (under#if NET5_0_OR_GREATER), andCompatibilitySuppressions.xmllists theirs but not this one.Repro (verified: compiled and ran against current main,
<Nullable>enable</Nullable>)The same code with
InsertionOrderMap<string, string>gets a CS8600 warning, as it should.Why it matters
Nullable flow analysis is wrong for one of the three map types. A caller that switches from
InsertionOrderMaptoContiguousMapfor performance silently loses the null-safety check. The code also doesn't matchIDictionary<TKey, TValue>.TryGetValue, which is annotated[MaybeNullWhen(false)].Suggested fix
Copy the pattern from
InsertionOrderMap.TryGetValue:Then add the matching entry to
CompatibilitySuppressions.xml, the same way the other two maps did.Acceptance criteria