erl_lint: Add a deprecated warning for literal tuple funs

The run-time warning for use of tuple funs will not catch the use
of literal tuple funs, such as:

    if
	{erlang,'+'}(3,X) =:= 0 -> true;
	true -> false
    end.

Therefore, add a compile-time warning to give users some warning
before they stop working in R16.

1 files changed, 4 insertions, 1 deletions

diff --git a/lib/stdlib/src/erl_lint.erl b/lib/stdlib/src/erl_lint.erl
index abab81d31f..648ff349a4 100644
--- a/lib/stdlib/src/erl_lint.erl
+++ b/lib/stdlib/src/erl_lint.erl
@@ -248,6 +248,8 @@ format_error({illegal_guard_local_call, {F,A}}) ->
     io_lib:format("call to local/imported function ~w/~w is illegal in guard",
 		  [F,A]);
 format_error(illegal_guard_expr) -> "illegal guard expression";
+format_error(deprecated_tuple_fun) ->
+    "tuple funs are deprecated and will be removed in R16";
 %% --- exports ---
 format_error({explicit_export,F,A}) ->
     io_lib:format("in this release, the call to ~w/~w must be written "
@@ -1914,7 +1916,8 @@ gexpr({call,Line,{remote,_Lr,{atom,_Lm,erlang},{atom,_Lf,F}},As}, Vt, St0) ->
         true -> {Asvt,St1};
         false -> {Asvt,add_error(Line, illegal_guard_expr, St1)}
     end;
-gexpr({call,L,{tuple,Lt,[{atom,Lm,erlang},{atom,Lf,F}]},As}, Vt, St) ->
+gexpr({call,L,{tuple,Lt,[{atom,Lm,erlang},{atom,Lf,F}]},As}, Vt, St0) ->
+    St = add_warning(L, deprecated_tuple_fun, St0),
     gexpr({call,L,{remote,Lt,{atom,Lm,erlang},{atom,Lf,F}},As}, Vt, St);
 gexpr({op,Line,Op,A}, Vt, St0) ->
     {Avt,St1} = gexpr(A, Vt, St0),