Adds lint for assigning variables to themselves (#20744)

* Fixes some funny bugs, adds a lint to check for future

* Proven that the grep works, pushing this fix

code/datums/mind.dm

@@ -555,7 +555,6 @@
 		for(var/datum/antagonist/A in antag_datums)
 			objective = locate(href_list["obj_completed"]) in A.objectives
 			if(istype(objective))
-				objective = objective
 				break
 		if(!objective)
 			to_chat(usr,"Invalid objective.")

code/datums/wounds/bones.dm

@@ -187,8 +187,6 @@
 	else if(limb.body_zone in list(BODY_ZONE_L_ARM, BODY_ZONE_R_ARM))
 		if(limb.current_gauze)
 			interaction_efficiency_penalty = 1 + ((interaction_efficiency_penalty - 1) * limb.current_gauze.splint_factor)
-		else
-			interaction_efficiency_penalty = interaction_efficiency_penalty
 
 	if(initial(disabling))
 		set_disabling(!limb.current_gauze)

code/game/gamemodes/objective.dm

@@ -204,7 +204,7 @@ GLOBAL_LIST_EMPTY(objectives)
 /datum/objective/proc/copy_target(datum/objective/old_obj)
 	target = old_obj.get_target()
 	target_amount = old_obj.target_amount
-	explanation_text = explanation_text
+	explanation_text = old_obj.explanation_text
 
 /datum/objective/assassinate
 	name = "assassinate"

code/game/say.dm

@@ -175,7 +175,7 @@ GLOBAL_LIST_INIT(freqtospan, list(
 INITIALIZE_IMMEDIATE(/atom/movable/virtualspeaker)
 /atom/movable/virtualspeaker/Initialize(mapload, atom/movable/M, radio)
 	. = ..()
-	radio = radio
+	src.radio = radio
 	source = M
 	if (istype(M))
 		name = M.GetVoice()

code/modules/admin/sql_message_system.dm

@@ -310,7 +310,6 @@
 		if(!new_severity)
 			qdel(query_find_edit_note_severity)
 			return
-		new_severity = new_severity
 		var/edit_text = "Note severity edited by [editor_key] on [SQLtime()] from [old_severity] to [new_severity]<hr>"
 		var/datum/DBQuery/query_edit_note_severity = SSdbcore.NewQuery({"
 			UPDATE [format_table_name("messages")]

code/modules/admin/verbs/SDQL2/SDQL_2_parser.dm

@@ -477,9 +477,11 @@
 			// And these 3 lines prevent it from happening while being quiet.
 			// So.. it works.
 			// Don't touch it.
-			var/whatthefuck = i
-			whatthefuck = src.type
-			whatthefuck = whatthefuck
+			// Looks like the bug got fixed, it works commented out now
+			// If it breaks again, try uncommenting
+			// var/whatthefuck = i
+			// whatthefuck = src.type
+			// whatthefuck = whatthefuck
 
 		while(token(i) && token(i) != "]")
 

code/modules/spells/spell_types/devil.dm

@@ -154,7 +154,7 @@
 	var/obj/effect/dummy/phased_mob/holder = new /obj/effect/dummy/phased_mob(loc)
 	extinguish_mob()
 	forceMove(holder)
-	holder = holder
+	src.holder = holder
 	notransform = FALSE
 	fakefireextinguish()
 

tools/travis/check_grep.sh

@@ -63,6 +63,10 @@ if grep -P '^/(obj|mob|turf|area|atom)/.+/Initialize\((?!mapload).*\)' code/**/*
 	echo "ERROR: Initialize override without 'mapload' argument."
 	st=1
 fi;
+if grep -P '^\s*(\w+)\s*=\s*(\1)\b\s*$' code/**/*.dm; then
+	echo "ERROR: Variable is assigned to itself"
+	st=1
+fi;
 for json in _maps/*.json
 do
     filename="_maps/$(jq -r '.map_path' $json)/$(jq -r '.map_file' $json)"