Fix bug #5141: Bogus message "Error: Cannot infer type of pattern-matching".
Fix bug #5141: Bogus message "Error: Cannot infer type of pattern-matching".

We simply explicit that the type is actually referring to the return type,
not to the type of the argument of the pattern-matching. Note that the
heuristic could be enhanced so as to use the same code in both let-style
and match-style pattern-matching, but I'm leaving this for another time.

Matafou/coq,Zimmi48/coq,amintimany/coq,Zimmi48/coq,maximedenes/coq,coq/coq,coq/coq,william-lawvere/coq,Zimmi48/coq,ppedrot/coq,ppedrot/coq,ejgallego/coq,SkySkimmer/coq,Lionel-Rieg/coq,ppedrot/coq,SkySkimmer/coq,silene/coq,JasonGross/coq,JasonGross/coq,maximedenes/coq,letouzey/coq-wip,gares/coq,JasonGross/coq,Lionel-Rieg/coq,gares/coq,Lionel-Rieg/coq,ejgallego/coq,ppedrot/coq,gares/coq,silene/coq,coq/coq,ppedrot/coq,Ptival/coq,Matafou/coq,JasonGross/coq,coq/coq,amintimany/coq,ejgallego/coq,maximedenes/coq,Matafou/coq,letouzey/coq-wip,SkySkimmer/coq,Ptival/coq,maximedenes/coq,maximedenes/coq,william-lawvere/coq,SkySkimmer/coq,letouzey/coq-wip,letouzey/coq-wip,silene/coq,Ptival/coq,letouzey/coq-wip,william-lawvere/coq,gares/coq,ejgallego/coq,Zimmi48/coq,amintimany/coq,gares/coq