Binding operators (let*, and+ etc) don't work in merlin-occurrences or merlin-locate, for various reasons:

• Uses of the operators as such (ie, not the function syntax as in (let*)) aren't found at all
• Reconstructing the identifier from a location doesn't work (the lexer used doesn't seem to know about the syntax)

I have an addendum to PR #1385 that parses these operators for Emacs Xref but it doesn't work without help from the merlin machinery.

Issue #949 seems to be related.