[inliner] don't generate `_this` for static or local function

src/optimization/inline.ml

@@ -429,13 +429,21 @@ class inline_state ctx ethis params cf f p = object(self)
 		(*
 			Build the expr/var subst list
 		*)
-		let ethis = (match ethis.eexpr with TConst TSuper -> { ethis with eexpr = TConst TThis } | _ -> ethis) in
-		let vthis = alloc_var VInlined "_this" ethis.etype ethis.epos in
-		let args1 = (ethis :: params) in
-		let args2 = ((vthis,None) :: f.tf_args) in
-		let vars = loop [] args1 args2 true in
-		_inlined_vars <- vars; (* Order is reversed due to tail-recursion *)
-		vthis
+		let set_inlined_vars args1 args2 =
+			let vars = loop [] args1 args2 true in
+			_inlined_vars <- vars; (* Order is reversed due to tail-recursion *)
+		in
+		match ethis.eexpr with
+		| TConst TNull ->
+			set_inlined_vars params f.tf_args;
+			None
+		| _ ->
+			let ethis = (match ethis.eexpr with TConst TSuper -> { ethis with eexpr = TConst TThis } | _ -> ethis) in
+			let vthis = alloc_var VInlined "_this" ethis.etype ethis.epos in
+			let args1 = (ethis :: params) in
+			let args2 = ((vthis,None) :: f.tf_args) in
+			set_inlined_vars args1 args2;
+			Some vthis
 
 	method finalize config e tl tret p =
 		let has_params,map_type = match config with Some config -> config | None -> inline_default_config cf ethis.etype in
@@ -578,7 +586,7 @@ let rec type_inline ctx cf f ethis params tret config p ?(self_calling_closure=f
 		| Some e -> Some e)
 	with Exit ->
 	let state = new inline_state ctx ethis params cf f p in
-	let vthis = state#initialize in
+	let vthis_opt = state#initialize in
 	let opt f = function
 		| None -> None
 		| Some e -> Some (f e)
@@ -609,9 +617,14 @@ let rec type_inline ctx cf f ethis params tret config p ?(self_calling_closure=f
 			let e = { e with eexpr = TLocal l.i_subst } in
 			if l.i_abstract_this then mk (TCast(e,None)) v.v_type e.epos else e
 		| TConst TThis ->
-			let l = state#read vthis in
-			l.i_read <- l.i_read + (if !in_loop then 2 else 1);
-			{ e with eexpr = TLocal l.i_subst }
+			(match vthis_opt with
+			| Some vthis ->
+				let l = state#read vthis in
+				l.i_read <- l.i_read + (if !in_loop then 2 else 1);
+				{ e with eexpr = TLocal l.i_subst }
+			| None ->
+				error "Could not inline `this` outside of an instance context" po
+			)
 		| TVar (v,eo) ->
 			{ e with eexpr = TVar ((state#declare v).i_subst,opt (map false false) eo)}
 		| TReturn eo when not state#in_local_fun ->