swift234

subsume the "startsWithGreater" logic into skipUntilGreaterInTypeList, and make sure skipUntilGreaterInTypeList return a valid location even in the case of parse errors.  This ensures that we form a valid source range.  Also, improve parseExprIdentifier() to handle the case when skipUntilGreaterInTypeList returns an empty archetype argument list.  This fixes a couple of compiler crashers.