diff --git a/builtins_base.js b/builtins_base.js
index fbfa82a..9fbd02f 100644
--- a/builtins_base.js
+++ b/builtins_base.js
@@ -314,21 +314,28 @@ module.exports = {
 		'__dfhack_random.init': 'none',
 		'__dfhack_random.random': 'number',
 		'__dfhack_random.drandom': 'number',
+		'dfhack.units.getCasteProfessionName': 'string',
+		'dfhack.units.getNemesis': 'df.nemesis_record',
+		'dfhack.units.getPosition': { _type:'tuple', _tuple:['number', 'number', 'number'] },
+		'dfhack.units.getProfessionColor': 'number',
 		'dfhack.units.getProfessionName': 'string',
+		'dfhack.units.getVisibleName': 'df.language_name',
+		'dfhack.units.isActive': 'bool',
+		'dfhack.units.isBaby': 'bool',
+		'dfhack.units.isChild': 'bool',
 		'dfhack.units.isCitizen': 'bool',
+		'dfhack.units.isDead': 'bool',
+		'dfhack.units.isDiplomat': 'bool',
+		'dfhack.units.isFemale': 'bool',
+		'dfhack.units.isMale': 'bool',
+		'dfhack.units.isMarkedForSlaughter': 'bool',
+		'dfhack.units.isMerchant': 'bool',
+		'dfhack.units.isOpposedToLife': 'bool',
 		'dfhack.units.isOwnCiv': 'bool',
-		'dfhack.units.getVisibleName': 'df.language_name',
-		'dfhack.units.getProfessionColor': 'number',
-		'dfhack.units.getNemesis': 'df.nemesis_record',
-		'dfhack.units.getPosition': { _type:'tuple', _tuple:['number', 'number', 'number'] },
-		'dfhack.units.getCasteProfessionName': 'string',
-		'dfhack.units.setNickname': 'none',
 		'dfhack.units.isOwnGroup': 'bool',
+		'dfhack.units.isOwnRace': 'bool',
 		'dfhack.units.isSane': 'bool',
-		'dfhack.units.isDead': 'bool',
-		'dfhack.units.isOpposedToLife': 'bool',
-		'dfhack.units.isMale': 'bool',
-		'dfhack.units.isFemale': 'bool',
+		'dfhack.units.setNickname': 'none',
 		'dfhack.units.getNoblePositions': {
 			_type: 'table',
 			_array: {
@@ -379,6 +386,7 @@ module.exports = {
 		'dfhack.maps.ensureTileBlock': 'df.map_block',
 		'dfhack.maps.getTileType': 'df.tiletype',
 		'dfhack.maps.getTileFlags': { _type:'tuple', _tuple:['df.tile_designation', 'df.tile_occupancy'] },
+		'dfhack.maps.isValidTilePos': 'bool',
 		'dfhack.maps.spawnFlow': 'df.flow_info',
 		'dfhack.maps.enableBlockUpdates': 'none',
 		'dfhack.burrows.setAssignedUnit': 'none',
diff --git a/index.js b/index.js
index d827f25..3e8a1fd 100644
--- a/index.js
+++ b/index.js
@@ -121,7 +121,7 @@ function deepEqual(a, b, ctx, line) {
 	if (b == 'null') {
 		return true;
 	}
-	if (a && b && (Object.hasOwnProperty.call(a, '_value') || Object.hasOwnProperty.call(b, '_value')) && (a._type||a) == (b._type||b)) {
+	if (a && b && (Object.hasOwnProperty.call(a, '_value') || Object.hasOwnProperty.call(b, '_value') || (a._type||a) == 'number' || (b._type||b) == 'number') && (a._type||a) == (b._type||b)) {
 		return true;
 	}
 	if (typeof a != typeof b) {
@@ -1764,6 +1764,9 @@ function merge(a, b, ctx, line, quiet) {
 	if (b == 'null') {
 		return a;
 	}
+	if ((a._type||a) == 'number' && (b._type||b) == 'bool') {
+		return 'number'; // allow assigning true/false to bitfields
+	}
 	if (((a._type||a) == '__arg' && isargtype(b._type||b)) || ((b._type||b) == '__arg' && isargtype(a._type||a))) {
 		return '__arg';
 	}
@@ -2553,7 +2556,7 @@ function processAST(body, ctx) {
 					var t = checktype(clause.condition, ctx2, { in_if:true });
 					// if (t == '__unknown')
 					//	err(b.loc.start.line, 'type of expression is unknown', chalk.bold(sub(clause.condition.range)));
-					if (t && t._type == 'bool' && !t._value) {
+					if (t && t._type == 'bool' && Object.hasOwnProperty.call(t, '_value') && !t._value) {
 						if (verbose > 1) {
 							note(clause.loc.start.line, 'skipping if statement', chalk.bold(sub(clause.condition.range)), '(condition is always false)');
 						}
diff --git a/luacheck.sh b/luacheck.sh
index bf75ec9..20f57eb 100755
--- a/luacheck.sh
+++ b/luacheck.sh
@@ -48,6 +48,9 @@ if (( $# > 0 )); then
 	done
 else
 	find "$dfhack_dir/scripts" -name '*.lua' -print0 | while IFS= read -r -d $'\0' script_path; do
+		if grep -qF "luacheck:skip-entirely" "$script_path"; then
+			continue
+		fi
 		node "$luacheck_dir/index.js" $args -v "$dfhack_version" -S "$dfhack_dir/scripts" -I "$dfhack_dir/library/lua" -I "$dfhack_dir/scripts" -p dfhack "$script_path"
 		if (( $? > 0 )); then had_error=1; fi
 	done
diff --git a/prepare.js b/prepare.js
index e4c09de..096b57d 100644
--- a/prepare.js
+++ b/prepare.js
@@ -490,6 +490,10 @@ pending_index_enums.forEach(function(e) {
 Object.keys(rootctx.functions || {}).forEach(function(f) {
 	var path = f.split(/\./g);
 	var t = rootctx.types;
+	if (path.length == 2 && path[0] == 'string') {
+		rootctx.functions['__arg.' + path[1]] = rootctx.functions[f];
+	}
+
 	for (var i = 0; i < path.length - 1; i++) {
 		if (!t[path[i]]) {
 			t[path[i]] = {