DependentProjectsFinder.GetAssemblyReferenceType might perform unnecessary binding

[sharwell]

The DependentProjectsFinder.GetAssemblyReferenceType method obtains an assembly or module symbol here:

roslyn/src/Workspaces/Core/Portable/FindSymbols/FindReferences/DependentProjectsFinder.cs

Line 458 in e056778

if (compilation.GetAssemblyOrModuleSymbol(reference) is IAssemblySymbol symbol)

This symbol is passed to a predicate, where the only actual use of this predicate is the following:

roslyn/src/Workspaces/Core/Portable/FindSymbols/FindReferences/DependentProjectsFinder.cs

Line 419 in e056778

a => a.Name == assemblyName ? true : (bool?)null,

The HasReferenceToAssembly method should be updated to avoid requiring symbol binding to check the name of an assembly.

🔗 Originally discovered while investigating internal issue DevDiv 1006914.

[bleroy]

FWIW, still repros in 16.5 Preview 3.

[sharwell]

😨 This was responsible for 3.5GiB allocations in a 100 second performance trace taken with 16.9 Preview 2 (IntPreview 1a8a572).

[CyrusNajmabadi]

Any suggestions on an alternate path to take? If this is a PEReference we could attempt to crack it open directly. But that seems non-ideal. Esp. as i would hope we could get an IAssemblySymbol cheaply to do this check. Should this maybe go to compiler to see if htey can mkae things faster or more lightweight here?