add pf_ignore_unsafe_cast and use it to optimize in promote_complex_rhs (closes #2175)

codegen.ml

@@ -857,6 +857,8 @@ let promote_complex_rhs ctx e =
 			{ e with eexpr = TMeta(m,loop f e1)}
 		| TReturn _ | TThrow _ ->
 			find e
+		| TCast(e1,None) when ctx.config.pf_ignore_unsafe_cast ->
+			loop f e1
 		| _ ->
 			f (find e)
 	and block el =

common.ml

@@ -97,6 +97,8 @@ type platform_config = {
 	pf_pattern_matching : bool;
 	(** can the platform use default values for non-nullable arguments *)
 	pf_can_skip_non_nullable_argument : bool;
+	(** generator ignores TCast(_,None) *)
+	pf_ignore_unsafe_cast : bool;
 }
 
 type context = {
@@ -452,6 +454,7 @@ let default_config =
 		pf_overload = false;
 		pf_pattern_matching = false;
 		pf_can_skip_non_nullable_argument = true;
+		pf_ignore_unsafe_cast = false;
 	}
 
 let get_config com =
@@ -473,6 +476,7 @@ let get_config com =
 			pf_overload = false;
 			pf_pattern_matching = false;
 			pf_can_skip_non_nullable_argument = true;
+			pf_ignore_unsafe_cast = false;
 		}
 	| Js ->
 		{
@@ -488,6 +492,7 @@ let get_config com =
 			pf_overload = false;
 			pf_pattern_matching = false;
 			pf_can_skip_non_nullable_argument = true;
+			pf_ignore_unsafe_cast = true;
 		}
 	| Neko ->
 		{
@@ -503,6 +508,7 @@ let get_config com =
 			pf_overload = false;
 			pf_pattern_matching = false;
 			pf_can_skip_non_nullable_argument = true;
+			pf_ignore_unsafe_cast = true;
 		}
 	| Flash when defined Define.As3 ->
 		{
@@ -518,6 +524,7 @@ let get_config com =
 			pf_overload = false;
 			pf_pattern_matching = false;
 			pf_can_skip_non_nullable_argument = false;
+			pf_ignore_unsafe_cast = false;
 		}
 	| Flash ->
 		{
@@ -533,6 +540,7 @@ let get_config com =
 			pf_overload = false;
 			pf_pattern_matching = false;
 			pf_can_skip_non_nullable_argument = false;
+			pf_ignore_unsafe_cast = false;
 		}
 	| Php ->
 		{
@@ -553,6 +561,7 @@ let get_config com =
 			pf_overload = false;
 			pf_pattern_matching = false;
 			pf_can_skip_non_nullable_argument = true;
+			pf_ignore_unsafe_cast = false;
 		}
 	| Cpp ->
 		{
@@ -568,6 +577,7 @@ let get_config com =
 			pf_overload = false;
 			pf_pattern_matching = false;
 			pf_can_skip_non_nullable_argument = true;
+			pf_ignore_unsafe_cast = false;
 		}
 	| Cs ->
 		{
@@ -583,6 +593,7 @@ let get_config com =
 			pf_overload = true;
 			pf_pattern_matching = false;
 			pf_can_skip_non_nullable_argument = true;
+			pf_ignore_unsafe_cast = false;
 		}
 	| Java ->
 		{
@@ -598,6 +609,7 @@ let get_config com =
 			pf_overload = true;
 			pf_pattern_matching = false;
 			pf_can_skip_non_nullable_argument = true;
+			pf_ignore_unsafe_cast = false;
 		}
 
 let create v args =