An opportunity for optimization in ImmutableArrayExtensions.CreateNameToMembersMap

[AlekseyTs]

roslyn/src/Compilers/Core/Portable/Collections/ImmutableArrayExtensions.cs

Lines 934 to 938 in 7c23c2e

	members = hasNamespaces
	? builder.ToImmutable()
	: ImmutableArray<TNamespaceOrTypeSymbol>.CastUp(builder.ToDowncastedImmutable<TNamedTypeSymbol>());
	builder.Free();

One branch could do builder.ToImmutableAndFree(), which would allow for the optimization of moving the internal array to the immutable array without a copy.

[jcouv]

Assigned to @CyrusNajmabadi since he already has a fix in review.