Restore the corner-case behaviour for let-bound variables in patterns.
Restore the corner-case behaviour for let-bound variables in patterns.

Zimmi48/coq,ejgallego/coq,coq/coq,Zimmi48/coq,JasonGross/coq,silene/coq,coq/coq,ejgallego/coq,ejgallego/coq,silene/coq,coq/coq,JasonGross/coq,ejgallego/coq,SkySkimmer/coq,coq/coq,Zimmi48/coq,SkySkimmer/coq,Zimmi48/coq,SkySkimmer/coq,SkySkimmer/coq,JasonGross/coq,JasonGross/coq,silene/coq