fix #4414, better error message for uncurried function

Author: bobzhang

jscomp/super_errors/super_typecore.ml

@@ -253,6 +253,10 @@ let report_error env ppf = function
         fprintf ppf "it should have type@ %a@]"
           type_expr ty
       end else begin
+        match ty with 
+        | {desc = Tconstr (Pdot (Pdot(Pident {name = "Js"},"Fn",_),_,_),_,_)} -> 
+          fprintf ppf "This expression is excpeted to have an uncurried function"
+        | _ ->     
         fprintf ppf "@[This expression should not be a function,@ ";
         fprintf ppf "the expected type is@ %a@]"
           type_expr ty

lib/4.06.1/unstable/js_compiler.ml

@@ -62983,6 +62983,10 @@ let report_error env ppf = function
         fprintf ppf "it should have type@ %a"
           type_expr ty
       end else begin
+        match ty with 
+        | {desc = Tconstr (Pdot (Pdot(Pident {name = "Js"},"Fn",_),_,_),_,_)} -> 
+          fprintf ppf "This expression is excpeted to have an uncurried function"
+        | _ ->   
         fprintf ppf "This expression should not be a function,@ ";
         fprintf ppf "the expected type is@ %a"
           type_expr ty
@@ -412663,6 +412667,10 @@ let report_error env ppf = function
         fprintf ppf "it should have type@ %a@]"
           type_expr ty
       end else begin
+        match ty with 
+        | {desc = Tconstr (Pdot (Pdot(Pident {name = "Js"},"Fn",_),_,_),_,_)} -> 
+          fprintf ppf "This expression is excpeted to have an uncurried function"
+        | _ ->     
         fprintf ppf "@[This expression should not be a function,@ ";
         fprintf ppf "the expected type is@ %a@]"
           type_expr ty

lib/4.06.1/unstable/js_refmt_compiler.ml

@@ -62983,6 +62983,10 @@ let report_error env ppf = function
         fprintf ppf "it should have type@ %a"
           type_expr ty
       end else begin
+        match ty with 
+        | {desc = Tconstr (Pdot (Pdot(Pident {name = "Js"},"Fn",_),_,_),_,_)} -> 
+          fprintf ppf "This expression is excpeted to have an uncurried function"
+        | _ ->   
         fprintf ppf "This expression should not be a function,@ ";
         fprintf ppf "the expected type is@ %a"
           type_expr ty
@@ -572759,6 +572763,10 @@ let report_error env ppf = function
         fprintf ppf "it should have type@ %a@]"
           type_expr ty
       end else begin
+        match ty with 
+        | {desc = Tconstr (Pdot (Pdot(Pident {name = "Js"},"Fn",_),_,_),_,_)} -> 
+          fprintf ppf "This expression is excpeted to have an uncurried function"
+        | _ ->     
         fprintf ppf "@[This expression should not be a function,@ ";
         fprintf ppf "the expected type is@ %a@]"
           type_expr ty

lib/4.06.1/whole_compiler.ml

@@ -348377,6 +348377,10 @@ let report_error env ppf = function
         fprintf ppf "it should have type@ %a"
           type_expr ty
       end else begin
+        match ty with 
+        | {desc = Tconstr (Pdot (Pdot(Pident {name = "Js"},"Fn",_),_,_),_,_)} -> 
+          fprintf ppf "This expression is excpeted to have an uncurried function"
+        | _ ->   
         fprintf ppf "This expression should not be a function,@ ";
         fprintf ppf "the expected type is@ %a"
           type_expr ty
@@ -419981,6 +419985,10 @@ let report_error env ppf = function
         fprintf ppf "it should have type@ %a@]"
           type_expr ty
       end else begin
+        match ty with 
+        | {desc = Tconstr (Pdot (Pdot(Pident {name = "Js"},"Fn",_),_,_),_,_)} -> 
+          fprintf ppf "This expression is excpeted to have an uncurried function"
+        | _ ->     
         fprintf ppf "@[This expression should not be a function,@ ";
         fprintf ppf "the expected type is@ %a@]"
           type_expr ty