Using a single, optional, static parameter to a type provider causes failure

[KevinRansom]

Originally opened on CodePlex by [latkin](Using a single, optional, static parameter to a type provider causes failure)
[originally reported to fsbugs]

Repro solution attached

If one creates a type provider with a single, optional, static parameter (i.e. single parameter with a default value specified), two scenarios are broken:

• Omitting the optional parameter
• Including the optional parameter, when the value matches the specified default

E.g. TP "Test" has single string optional arg, with default value "Foo":
Image

Fix strategy, per Vlad:
"Fix seems to be trivial - one line addition in name demangling routine (demangleProvidedTypeName in PrettyNaming.fs)"

Repro: