diff --git a/vlib/builtin/array.v b/vlib/builtin/array.v
index b2dee67c15..665f215ada 100644
--- a/vlib/builtin/array.v
+++ b/vlib/builtin/array.v
@@ -636,7 +636,7 @@ fn (mut a array) push(val voidptr) {
 // `val` is array.data and user facing usage is `a << [1,2,3]`
 [unsafe]
 pub fn (mut a3 array) push_many(val voidptr, size int) {
-	if size <= 0 || isnil(val) {
+	if size <= 0 || val == unsafe { nil } {
 		return
 	}
 	a3.ensure_cap(a3.len + size)
diff --git a/vlib/builtin/array_d_gcboehm_opt.v b/vlib/builtin/array_d_gcboehm_opt.v
index 238b6300a2..9f8a5bab3e 100644
--- a/vlib/builtin/array_d_gcboehm_opt.v
+++ b/vlib/builtin/array_d_gcboehm_opt.v
@@ -227,7 +227,7 @@ fn (mut a array) push_noscan(val voidptr) {
 // `val` is array.data and user facing usage is `a << [1,2,3]`
 [unsafe]
 fn (mut a3 array) push_many_noscan(val voidptr, size int) {
-	if size <= 0 || isnil(val) {
+	if size <= 0 || val == unsafe { nil } {
 		return
 	}
 	if a3.data == val && a3.data != 0 {
diff --git a/vlib/builtin/builtin_d_use_libbacktrace.c.v b/vlib/builtin/builtin_d_use_libbacktrace.c.v
index d4f344fc18..90f2688b42 100644
--- a/vlib/builtin/builtin_d_use_libbacktrace.c.v
+++ b/vlib/builtin/builtin_d_use_libbacktrace.c.v
@@ -38,8 +38,12 @@ struct BacktraceOptions {
 }
 
 fn bt_print_callback(data &BacktraceOptions, pc voidptr, filename_ptr &char, line int, fn_name_ptr &char) int {
-	filename := if isnil(filename_ptr) { '???' } else { unsafe { filename_ptr.vstring() } }
-	fn_name := if isnil(fn_name_ptr) {
+	filename := if filename_ptr == unsafe { nil } {
+		'???'
+	} else {
+		unsafe { filename_ptr.vstring() }
+	}
+	fn_name := if fn_name_ptr == unsafe { nil } {
 		'???'
 	} else {
 		(unsafe { fn_name_ptr.vstring() }).replace('__', '.')
@@ -56,7 +60,7 @@ fn bt_print_callback(data &BacktraceOptions, pc voidptr, filename_ptr &char, lin
 }
 
 fn bt_error_callback(data voidptr, msg_ptr &char, errnum int) {
-	// if !isnil(data) && !isnil(data.state) && !isnil(data.state.filename) {
+	// if data != unsafe { nil } && data.state != unsafe { nil } && data.state.filename != unsafe { nil } {
 	// 	filename := unsafe{ data.state.filename.vstring() }
 	// 	eprint('$filename: ')
 	// }
diff --git a/vlib/builtin/builtin_nix.c.v b/vlib/builtin/builtin_nix.c.v
index 539ecbe217..871dc84428 100644
--- a/vlib/builtin/builtin_nix.c.v
+++ b/vlib/builtin/builtin_nix.c.v
@@ -96,7 +96,7 @@ fn print_backtrace_skipping_top_frames_linux(skipframes int) bool {
 				cmd := 'addr2line -e $executable $addr'
 				// taken from os, to avoid depending on the os module inside builtin.v
 				f := C.popen(&char(cmd.str), c'r')
-				if isnil(f) {
+				if f == unsafe { nil } {
 					eprintln(sframe)
 					continue
 				}
diff --git a/vlib/builtin/sorted_map.v b/vlib/builtin/sorted_map.v
index 7893ad00c7..ec90dcada2 100644
--- a/vlib/builtin/sorted_map.v
+++ b/vlib/builtin/sorted_map.v
@@ -73,7 +73,7 @@ fn (mut m SortedMap) set(key string, value voidptr) {
 	mut parent := &mapnode(0)
 	for {
 		if node.len == max_len {
-			if isnil(parent) {
+			if parent == unsafe { nil } {
 				parent = new_node()
 				m.root = parent
 			}
@@ -100,7 +100,7 @@ fn (mut m SortedMap) set(key string, value voidptr) {
 			}
 			return
 		}
-		if isnil(node.children) {
+		if node.children == unsafe { nil } {
 			mut j := node.len - 1
 			for j >= 0 && key < node.keys[j] {
 				node.keys[j + 1] = node.keys[j]
@@ -130,7 +130,7 @@ fn (mut n mapnode) split_child(child_index int, mut y mapnode) {
 		z.keys[j] = y.keys[j + degree]
 		z.values[j] = y.values[j + degree]
 	}
-	if !isnil(y.children) {
+	if y.children != unsafe { nil } {
 		z.children = unsafe { &voidptr(malloc(int(children_bytes))) }
 		for jj := degree - 1; jj >= 0; jj-- {
 			unsafe {
@@ -139,7 +139,7 @@ fn (mut n mapnode) split_child(child_index int, mut y mapnode) {
 		}
 	}
 	unsafe {
-		if isnil(n.children) {
+		if n.children == nil {
 			n.children = &voidptr(malloc(int(children_bytes)))
 		}
 		n.children[n.len + 1] = n.children[n.len]
@@ -173,7 +173,7 @@ fn (m SortedMap) get(key string, out voidptr) bool {
 			}
 			return true
 		}
-		if isnil(node.children) {
+		if node.children == unsafe { nil } {
 			break
 		}
 		node = unsafe { &mapnode(node.children[i + 1]) }
@@ -182,7 +182,7 @@ fn (m SortedMap) get(key string, out voidptr) bool {
 }
 
 fn (m SortedMap) exists(key string) bool {
-	if isnil(m.root) { // TODO: find out why root can be nil
+	if m.root == unsafe { nil } { // TODO: find out why root can be nil
 		return false
 	}
 	mut node := m.root
@@ -194,7 +194,7 @@ fn (m SortedMap) exists(key string) bool {
 		if i != -1 && key == node.keys[i] {
 			return true
 		}
-		if isnil(node.children) {
+		if node.children == unsafe { nil } {
 			break
 		}
 		node = unsafe { &mapnode(node.children[i + 1]) }
@@ -213,14 +213,14 @@ fn (n &mapnode) find_key(k string) int {
 fn (mut n mapnode) remove_key(k string) bool {
 	idx := n.find_key(k)
 	if idx < n.len && n.keys[idx] == k {
-		if isnil(n.children) {
+		if n.children == unsafe { nil } {
 			n.remove_from_leaf(idx)
 		} else {
 			n.remove_from_non_leaf(idx)
 		}
 		return true
 	} else {
-		if isnil(n.children) {
+		if n.children == unsafe { nil } {
 			return false
 		}
 		flag := if idx == n.len { true } else { false }
@@ -250,7 +250,7 @@ fn (mut n mapnode) remove_from_non_leaf(idx int) {
 	k := n.keys[idx]
 	if unsafe { &mapnode(n.children[idx]) }.len >= degree {
 		mut current := unsafe { &mapnode(n.children[idx]) }
-		for !isnil(current.children) {
+		for current.children != unsafe { nil } {
 			current = unsafe { &mapnode(current.children[current.len]) }
 		}
 		predecessor := current.keys[current.len - 1]
@@ -260,7 +260,7 @@ fn (mut n mapnode) remove_from_non_leaf(idx int) {
 		node.remove_key(predecessor)
 	} else if unsafe { &mapnode(n.children[idx + 1]) }.len >= degree {
 		mut current := unsafe { &mapnode(n.children[idx + 1]) }
-		for !isnil(current.children) {
+		for current.children != unsafe { nil } {
 			current = unsafe { &mapnode(current.children[0]) }
 		}
 		successor := current.keys[0]
@@ -294,7 +294,7 @@ fn (mut n mapnode) borrow_from_prev(idx int) {
 		child.keys[i + 1] = child.keys[i]
 		child.values[i + 1] = child.values[i]
 	}
-	if !isnil(child.children) {
+	if child.children != unsafe { nil } {
 		for i := child.len; i >= 0; i-- {
 			unsafe {
 				child.children[i + 1] = child.children[i]
@@ -303,7 +303,7 @@ fn (mut n mapnode) borrow_from_prev(idx int) {
 	}
 	child.keys[0] = n.keys[idx - 1]
 	child.values[0] = n.values[idx - 1]
-	if !isnil(child.children) {
+	if child.children != unsafe { nil } {
 		unsafe {
 			child.children[0] = sibling.children[sibling.len]
 		}
@@ -319,7 +319,7 @@ fn (mut n mapnode) borrow_from_next(idx int) {
 	mut sibling := unsafe { &mapnode(n.children[idx + 1]) }
 	child.keys[child.len] = n.keys[idx]
 	child.values[child.len] = n.values[idx]
-	if !isnil(child.children) {
+	if child.children != unsafe { nil } {
 		unsafe {
 			child.children[child.len + 1] = sibling.children[0]
 		}
@@ -330,7 +330,7 @@ fn (mut n mapnode) borrow_from_next(idx int) {
 		sibling.keys[i - 1] = sibling.keys[i]
 		sibling.values[i - 1] = sibling.values[i]
 	}
-	if !isnil(sibling.children) {
+	if sibling.children != unsafe { nil } {
 		for i := 1; i <= sibling.len; i++ {
 			unsafe {
 				sibling.children[i - 1] = sibling.children[i]
@@ -350,7 +350,7 @@ fn (mut n mapnode) merge(idx int) {
 		child.keys[i + degree] = sibling.keys[i]
 		child.values[i + degree] = sibling.values[i]
 	}
-	if !isnil(child.children) {
+	if child.children != unsafe { nil } {
 		for i := 0; i <= sibling.len; i++ {
 			unsafe {
 				child.children[i + degree] = sibling.children[i]
@@ -383,7 +383,7 @@ pub fn (mut m SortedMap) delete(key string) {
 
 	if m.root.len == 0 {
 		// tmp := t.root
-		if isnil(m.root.children) {
+		if m.root.children == unsafe { nil } {
 			return
 		} else {
 			m.root = unsafe { &mapnode(m.root.children[0]) }
@@ -396,7 +396,7 @@ pub fn (mut m SortedMap) delete(key string) {
 // starting at `at`. Keys are inserted in order.
 fn (n &mapnode) subkeys(mut keys []string, at int) int {
 	mut position := at
-	if !isnil(n.children) {
+	if n.children != unsafe { nil } {
 		// Traverse children and insert
 		// keys inbetween children
 		for i in 0 .. n.len {
@@ -421,7 +421,7 @@ fn (n &mapnode) subkeys(mut keys []string, at int) int {
 
 pub fn (m &SortedMap) keys() []string {
 	mut keys := []string{len: m.len}
-	if isnil(m.root) || m.root.len == 0 {
+	if m.root == unsafe { nil } || m.root.len == 0 {
 		return keys
 	}
 	m.root.subkeys(mut keys, 0)
@@ -433,7 +433,7 @@ fn (mut n mapnode) free() {
 }
 
 pub fn (mut m SortedMap) free() {
-	if isnil(m.root) {
+	if m.root == unsafe { nil } {
 		return
 	}
 	m.root.free()
diff --git a/vlib/darwin/darwin.v b/vlib/darwin/darwin.v
index b85d8d71e9..36c72659b6 100644
--- a/vlib/darwin/darwin.v
+++ b/vlib/darwin/darwin.v
@@ -38,7 +38,7 @@ fn C.CFRelease(url &u8)
 pub fn resource_path() string {
 	main_bundle := C.CFBundleGetMainBundle()
 	resource_dir_url := C.CFBundleCopyResourcesDirectoryURL(main_bundle)
-	if isnil(resource_dir_url) {
+	if resource_dir_url == unsafe { nil } {
 		panic('CFBundleCopyResourcesDirectoryURL failed')
 	}
 	buffer_size := 4096
diff --git a/vlib/gg/gg.c.v b/vlib/gg/gg.c.v
index 380283c207..a4c1e2f54b 100644
--- a/vlib/gg/gg.c.v
+++ b/vlib/gg/gg.c.v
@@ -421,7 +421,7 @@ pub fn new_context(cfg Config) &Context {
 		ui_mode: cfg.ui_mode
 		native_rendering: cfg.native_rendering
 	}
-	if isnil(cfg.user_data) {
+	if cfg.user_data == unsafe { nil } {
 		ctx.user_data = ctx
 	}
 	ctx.set_bg_color(cfg.bg_color)
diff --git a/vlib/gx/image.v b/vlib/gx/image.v
index 4a20ea1fd0..890e516a0d 100644
--- a/vlib/gx/image.v
+++ b/vlib/gx/image.v
@@ -10,5 +10,5 @@ pub:
 }
 
 pub fn (i Image) is_empty() bool {
-	return isnil(i.obj)
+	return i.obj == unsafe { nil }
 }
diff --git a/vlib/sync/pool/pool.v b/vlib/sync/pool/pool.v
index 4727055b80..1ac7514347 100644
--- a/vlib/sync/pool/pool.v
+++ b/vlib/sync/pool/pool.v
@@ -42,7 +42,7 @@ pub struct PoolProcessorConfig {
 //      3) task_id - the index of the worker thread in which the callback
 //            function is running.
 pub fn new_pool_processor(context PoolProcessorConfig) &PoolProcessor {
-	if isnil(context.callback) {
+	if context.callback == unsafe { nil } {
 		panic('You need to pass a valid callback to new_pool_processor.')
 	}
 	mut pool := PoolProcessor{
diff --git a/vlib/v/ast/scope.v b/vlib/v/ast/scope.v
index 47f4e5da51..3722a7275d 100644
--- a/vlib/v/ast/scope.v
+++ b/vlib/v/ast/scope.v
@@ -38,7 +38,7 @@ pub fn new_scope(parent &Scope, start_pos int) &Scope {
 */
 
 fn (s &Scope) dont_lookup_parent() bool {
-	return isnil(s.parent) || s.detached_from_parent
+	return s.parent == unsafe { nil } || s.detached_from_parent
 }
 
 pub fn (s &Scope) find(name string) ?ScopeObject {
diff --git a/vlib/v/builder/msvc_windows.v b/vlib/v/builder/msvc_windows.v
index a76b412c7c..0604624a95 100644
--- a/vlib/v/builder/msvc_windows.v
+++ b/vlib/v/builder/msvc_windows.v
@@ -34,7 +34,7 @@ fn find_windows_kit_internal(key RegKey, versions []string) ?string {
 				}
 				alloc_length := (required_bytes + 2)
 				mut value := &u16(malloc_noscan(int(alloc_length)))
-				if isnil(value) {
+				if value == nil {
 					continue
 				}
 				//
diff --git a/vlib/v/checker/check_types.v b/vlib/v/checker/check_types.v
index b74aae40bf..bc28a80d6e 100644
--- a/vlib/v/checker/check_types.v
+++ b/vlib/v/checker/check_types.v
@@ -651,7 +651,8 @@ pub fn (mut c Checker) infer_fn_generic_types(func ast.Fn, mut node ast.CallExpr
 				} else {
 					match sym.info {
 						ast.Struct, ast.Interface, ast.SumType {
-							if !isnil(c.table.cur_fn) && c.table.cur_fn.generic_names.len > 0 { // in generic fn
+							if c.table.cur_fn != unsafe { nil }
+								&& c.table.cur_fn.generic_names.len > 0 { // in generic fn
 								if gt_name in c.table.cur_fn.generic_names
 									&& c.table.cur_fn.generic_names.len == c.table.cur_concrete_types.len {
 									idx := c.table.cur_fn.generic_names.index(gt_name)
@@ -704,7 +705,7 @@ pub fn (mut c Checker) infer_fn_generic_types(func ast.Fn, mut node ast.CallExpr
 					mut param_elem_sym := c.table.sym(param_elem_info.elem_type)
 					for {
 						if arg_elem_sym.kind == .array && param_elem_sym.kind == .array
-							&& !isnil(c.table.cur_fn)
+							&& c.table.cur_fn != unsafe { nil }
 							&& param_elem_sym.name !in c.table.cur_fn.generic_names {
 							arg_elem_info = arg_elem_sym.info as ast.Array
 							arg_elem_sym = c.table.sym(arg_elem_info.elem_type)
@@ -724,7 +725,7 @@ pub fn (mut c Checker) infer_fn_generic_types(func ast.Fn, mut node ast.CallExpr
 					mut param_elem_sym := c.table.sym(param_elem_info.elem_type)
 					for {
 						if arg_elem_sym.kind == .array_fixed && param_elem_sym.kind == .array_fixed
-							&& !isnil(c.table.cur_fn)
+							&& c.table.cur_fn != unsafe { nil }
 							&& param_elem_sym.name !in c.table.cur_fn.generic_names {
 							arg_elem_info = arg_elem_sym.info as ast.ArrayFixed
 							arg_elem_sym = c.table.sym(arg_elem_info.elem_type)
diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 029b9bbd36..d003e6da1d 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -955,7 +955,7 @@ pub fn (mut c Checker) check_expr_opt_call(expr ast.Expr, ret_type ast.Type) ast
 
 pub fn (mut c Checker) check_or_expr(node ast.OrExpr, ret_type ast.Type, expr_return_type ast.Type) {
 	if node.kind == .propagate_option {
-		if !isnil(c.table.cur_fn) && !c.table.cur_fn.return_type.has_flag(.optional)
+		if c.table.cur_fn != unsafe { nil } && !c.table.cur_fn.return_type.has_flag(.optional)
 			&& c.table.cur_fn.name != 'main.main' && !c.inside_const {
 			c.error('to propagate the call, `$c.table.cur_fn.name` must return an optional type',
 				node.pos)
@@ -972,7 +972,7 @@ pub fn (mut c Checker) check_or_expr(node ast.OrExpr, ret_type ast.Type, expr_re
 		return
 	}
 	if node.kind == .propagate_result {
-		if !isnil(c.table.cur_fn) && !c.table.cur_fn.return_type.has_flag(.result)
+		if c.table.cur_fn != unsafe { nil } && !c.table.cur_fn.return_type.has_flag(.result)
 			&& c.table.cur_fn.name != 'main.main' && !c.inside_const {
 			c.error('to propagate the call, `$c.table.cur_fn.name` must return an result type',
 				node.pos)
@@ -1093,7 +1093,7 @@ pub fn (mut c Checker) selector_expr(mut node ast.SelectorExpr) ast.Type {
 	match mut node.expr {
 		ast.Ident {
 			name := node.expr.name
-			valid_generic := util.is_generic_type_name(name) && !isnil(c.table.cur_fn)
+			valid_generic := util.is_generic_type_name(name) && c.table.cur_fn != unsafe { nil }
 				&& name in c.table.cur_fn.generic_names
 			if valid_generic {
 				name_type = ast.Type(c.table.find_type_idx(name)).set_flag(.generic)
@@ -1497,7 +1497,7 @@ fn (mut c Checker) stmt(node_ ast.Stmt) {
 			c.inside_const = false
 		}
 		ast.DeferStmt {
-			if node.idx_in_fn < 0 && !isnil(c.table.cur_fn) {
+			if node.idx_in_fn < 0 && c.table.cur_fn != unsafe { nil } {
 				node.idx_in_fn = c.table.cur_fn.defer_stmts.len
 				c.table.cur_fn.defer_stmts << unsafe { &node }
 			}
@@ -2035,7 +2035,7 @@ fn (mut c Checker) stmts_ending_with_expression(stmts []ast.Stmt) {
 }
 
 pub fn (mut c Checker) unwrap_generic(typ ast.Type) ast.Type {
-	if typ.has_flag(.generic) && !isnil(c.table.cur_fn) {
+	if typ.has_flag(.generic) && c.table.cur_fn != unsafe { nil } {
 		if t_typ := c.table.resolve_generic_to_concrete(typ, c.table.cur_fn.generic_names,
 			c.table.cur_concrete_types)
 		{
@@ -2629,13 +2629,13 @@ pub fn (mut c Checker) cast_expr(mut node ast.CastExpr) ast.Type {
 fn (mut c Checker) at_expr(mut node ast.AtExpr) ast.Type {
 	match node.kind {
 		.fn_name {
-			if isnil(c.table.cur_fn) {
+			if c.table.cur_fn == unsafe { nil } {
 				return ast.void_type
 			}
 			node.val = c.table.cur_fn.name.all_after_last('.')
 		}
 		.method_name {
-			if isnil(c.table.cur_fn) {
+			if c.table.cur_fn == unsafe { nil } {
 				return ast.void_type
 			}
 			fname := c.table.cur_fn.name.all_after_last('.')
@@ -2647,7 +2647,7 @@ fn (mut c Checker) at_expr(mut node ast.AtExpr) ast.Type {
 			}
 		}
 		.mod_name {
-			if isnil(c.table.cur_fn) {
+			if c.table.cur_fn == unsafe { nil } {
 				return ast.void_type
 			}
 			node.val = c.table.cur_fn.mod
@@ -3976,7 +3976,7 @@ pub fn (mut c Checker) goto_stmt(node ast.GotoStmt) {
 	if !c.inside_unsafe {
 		c.warn('`goto` requires `unsafe` (consider using labelled break/continue)', node.pos)
 	}
-	if !isnil(c.table.cur_fn) && node.name !in c.table.cur_fn.label_names {
+	if c.table.cur_fn != unsafe { nil } && node.name !in c.table.cur_fn.label_names {
 		c.error('unknown label `$node.name`', node.pos)
 	}
 	c.goto_labels[node.name]++ // Register a label use
diff --git a/vlib/v/checker/comptime.v b/vlib/v/checker/comptime.v
index 3e2d5e8709..0b4ef8534c 100644
--- a/vlib/v/checker/comptime.v
+++ b/vlib/v/checker/comptime.v
@@ -365,7 +365,7 @@ fn (mut c Checker) verify_all_vweb_routes() {
 				is_ok, nroute_attributes, nargs := c.verify_vweb_params_for_method(m)
 				if !is_ok {
 					f := &ast.FnDecl(m.source_fn)
-					if isnil(f) {
+					if f == unsafe { nil } {
 						continue
 					}
 					if f.return_type == typ_vweb_result && f.receiver.typ == m.params[0].typ
diff --git a/vlib/v/checker/containers.v b/vlib/v/checker/containers.v
index dbc51a8546..f29924c468 100644
--- a/vlib/v/checker/containers.v
+++ b/vlib/v/checker/containers.v
@@ -77,7 +77,7 @@ pub fn (mut c Checker) array_init(mut node ast.ArrayInit) ast.Type {
 			c.ensure_sumtype_array_has_default_value(node)
 		}
 		c.ensure_type_exists(node.elem_type, node.elem_type_pos) or {}
-		if node.typ.has_flag(.generic) && !isnil(c.table.cur_fn)
+		if node.typ.has_flag(.generic) && c.table.cur_fn != unsafe { nil }
 			&& c.table.cur_fn.generic_names.len == 0 {
 			c.error('generic struct cannot be used in non-generic function', node.pos)
 		}
diff --git a/vlib/v/checker/fn.v b/vlib/v/checker/fn.v
index e3b85930d9..7bd0c7de29 100644
--- a/vlib/v/checker/fn.v
+++ b/vlib/v/checker/fn.v
@@ -460,7 +460,7 @@ pub fn (mut c Checker) call_expr(mut node ast.CallExpr) ast.Type {
 	c.expected_or_type = node.return_type.clear_flag(.optional)
 	c.stmts_ending_with_expression(node.or_block.stmts)
 	c.expected_or_type = ast.void_type
-	if node.or_block.kind == .propagate_option && !isnil(c.table.cur_fn)
+	if node.or_block.kind == .propagate_option && c.table.cur_fn != unsafe { nil }
 		&& !c.table.cur_fn.return_type.has_flag(.optional) && !c.inside_const {
 		if !c.table.cur_fn.is_main {
 			c.error('to propagate the optional call, `$c.table.cur_fn.name` must return an optional',
@@ -486,7 +486,7 @@ pub fn (mut c Checker) fn_call(mut node ast.CallExpr, mut continue_check &bool)
 			concrete_types << concrete_type
 		}
 	}
-	if !isnil(c.table.cur_fn) && c.table.cur_concrete_types.len == 0 && has_generic {
+	if c.table.cur_fn != unsafe { nil } && c.table.cur_concrete_types.len == 0 && has_generic {
 		c.error('generic fn using generic types cannot be called outside of generic fn',
 			node.pos)
 	}
@@ -521,7 +521,7 @@ pub fn (mut c Checker) fn_call(mut node ast.CallExpr, mut continue_check &bool)
 			c.error('JS.await: first argument must be a promise, got `$tsym.name`', node.pos)
 			return ast.void_type
 		}
-		if !isnil(c.table.cur_fn) {
+		if c.table.cur_fn != unsafe { nil } {
 			c.table.cur_fn.has_await = true
 		}
 		match tsym.info {
@@ -787,7 +787,7 @@ pub fn (mut c Checker) fn_call(mut node ast.CallExpr, mut continue_check &bool)
 		&& func.mod != c.mod && !c.pref.is_test {
 		c.error('function `$func.name` is private', node.pos)
 	}
-	if !isnil(c.table.cur_fn) && !c.table.cur_fn.is_deprecated && func.is_deprecated {
+	if c.table.cur_fn != unsafe { nil } && !c.table.cur_fn.is_deprecated && func.is_deprecated {
 		c.deprecate('function', func.name, func.attrs, node.pos)
 	}
 	if func.is_unsafe && !c.inside_unsafe
@@ -1129,14 +1129,14 @@ pub fn (mut c Checker) fn_call(mut node ast.CallExpr, mut continue_check &bool)
 		}
 	}
 	// resolve return generics struct to concrete type
-	if func.generic_names.len > 0 && func.return_type.has_flag(.generic) && !isnil(c.table.cur_fn)
-		&& c.table.cur_fn.generic_names.len == 0 {
+	if func.generic_names.len > 0 && func.return_type.has_flag(.generic)
+		&& c.table.cur_fn != unsafe { nil } && c.table.cur_fn.generic_names.len == 0 {
 		node.return_type = c.table.unwrap_generic_type(func.return_type, func.generic_names,
 			concrete_types)
 	} else {
 		node.return_type = func.return_type
 	}
-	if node.concrete_types.len > 0 && func.return_type != 0 && !isnil(c.table.cur_fn)
+	if node.concrete_types.len > 0 && func.return_type != 0 && c.table.cur_fn != unsafe { nil }
 		&& c.table.cur_fn.generic_names.len == 0 {
 		if typ := c.table.resolve_generic_to_concrete(func.return_type, func.generic_names,
 			concrete_types)
@@ -1183,7 +1183,7 @@ pub fn (mut c Checker) method_call(mut node ast.CallExpr) ast.Type {
 	node.return_type = left_type
 	node.receiver_type = left_type
 
-	if !isnil(c.table.cur_fn) && c.table.cur_fn.generic_names.len > 0 {
+	if c.table.cur_fn != unsafe { nil } && c.table.cur_fn.generic_names.len > 0 {
 		c.table.unwrap_generic_type(left_type, c.table.cur_fn.generic_names, c.table.cur_concrete_types)
 	}
 	unwrapped_left_type := c.unwrap_generic(left_type)
@@ -1262,7 +1262,7 @@ pub fn (mut c Checker) method_call(mut node ast.CallExpr) ast.Type {
 		if node.args.len > 0 {
 			c.error('wait() does not have any arguments', node.args[0].pos)
 		}
-		if !isnil(c.table.cur_fn) {
+		if c.table.cur_fn != unsafe { nil } {
 			c.table.cur_fn.has_await = true
 		}
 		node.return_type = info.concrete_types[0]
@@ -1569,7 +1569,7 @@ pub fn (mut c Checker) method_call(mut node ast.CallExpr) ast.Type {
 			c.warn('method `${left_sym.name}.$method_name` must be called from an `unsafe` block',
 				node.pos)
 		}
-		if !isnil(c.table.cur_fn) && !c.table.cur_fn.is_deprecated && method.is_deprecated {
+		if c.table.cur_fn != unsafe { nil } && !c.table.cur_fn.is_deprecated && method.is_deprecated {
 			c.deprecate('method', '${left_sym.name}.$method.name', method.attrs, node.pos)
 		}
 		c.set_node_expected_arg_types(mut node, method)
@@ -1593,7 +1593,7 @@ pub fn (mut c Checker) method_call(mut node ast.CallExpr) ast.Type {
 
 		// resolve return generics struct to concrete type
 		if method.generic_names.len > 0 && method.return_type.has_flag(.generic)
-			&& !isnil(c.table.cur_fn) && c.table.cur_fn.generic_names.len == 0 {
+			&& c.table.cur_fn != unsafe { nil } && c.table.cur_fn.generic_names.len == 0 {
 			node.return_type = c.table.unwrap_generic_type(method.return_type, method.generic_names,
 				concrete_types)
 		} else {
diff --git a/vlib/v/checker/return.v b/vlib/v/checker/return.v
index cd7f27246e..1711bbab2e 100644
--- a/vlib/v/checker/return.v
+++ b/vlib/v/checker/return.v
@@ -7,7 +7,7 @@ import v.pref
 
 // TODO: non deferred
 pub fn (mut c Checker) return_stmt(mut node ast.Return) {
-	if isnil(c.table.cur_fn) {
+	if c.table.cur_fn == unsafe { nil } {
 		return
 	}
 	c.expected_type = c.table.cur_fn.return_type
diff --git a/vlib/v/checker/str.v b/vlib/v/checker/str.v
index de4cdc26bb..1a3816419e 100644
--- a/vlib/v/checker/str.v
+++ b/vlib/v/checker/str.v
@@ -104,8 +104,8 @@ pub fn (mut c Checker) string_inter_lit(mut node ast.StringInterLiteral) ast.Typ
 			node.need_fmts[i] = fmt != c.get_default_fmt(ftyp, typ)
 		}
 		// check recursive str
-		if !isnil(c.table.cur_fn) && c.table.cur_fn.is_method && c.table.cur_fn.name == 'str'
-			&& c.table.cur_fn.receiver.name == expr.str() {
+		if c.table.cur_fn != unsafe { nil } && c.table.cur_fn.is_method
+			&& c.table.cur_fn.name == 'str' && c.table.cur_fn.receiver.name == expr.str() {
 			c.error('cannot call `str()` method recursively', expr.pos())
 		}
 	}
diff --git a/vlib/v/checker/struct.v b/vlib/v/checker/struct.v
index 6de21c0425..d0eff93a73 100644
--- a/vlib/v/checker/struct.v
+++ b/vlib/v/checker/struct.v
@@ -244,7 +244,7 @@ pub fn (mut c Checker) struct_init(mut node ast.StructInit) ast.Type {
 				&& node.generic_types.len != struct_sym.info.generic_types.len {
 				c.error('generic struct init expects $struct_sym.info.generic_types.len generic parameter, but got $node.generic_types.len',
 					node.pos)
-			} else if node.generic_types.len > 0 && !isnil(c.table.cur_fn) {
+			} else if node.generic_types.len > 0 && c.table.cur_fn != unsafe { nil } {
 				for gtyp in node.generic_types {
 					gtyp_name := c.table.sym(gtyp).name
 					if gtyp_name !in c.table.cur_fn.generic_names {
@@ -276,7 +276,7 @@ pub fn (mut c Checker) struct_init(mut node ast.StructInit) ast.Type {
 		}
 	}
 	// register generic struct type when current fn is generic fn
-	if !isnil(c.table.cur_fn) && c.table.cur_fn.generic_names.len > 0 {
+	if c.table.cur_fn != unsafe { nil } && c.table.cur_fn.generic_names.len > 0 {
 		c.table.unwrap_generic_type(node.typ, c.table.cur_fn.generic_names, c.table.cur_concrete_types)
 	}
 	c.ensure_type_exists(node.typ, node.pos) or {}
@@ -321,7 +321,8 @@ pub fn (mut c Checker) struct_init(mut node ast.StructInit) ast.Type {
 				'it cannot be initialized with `$type_sym.name{}`', node.pos)
 		}
 	}
-	if type_sym.name.len == 1 && !isnil(c.table.cur_fn) && c.table.cur_fn.generic_names.len == 0 {
+	if type_sym.name.len == 1 && c.table.cur_fn != unsafe { nil }
+		&& c.table.cur_fn.generic_names.len == 0 {
 		c.error('unknown struct `$type_sym.name`', node.pos)
 		return ast.void_type
 	}
diff --git a/vlib/v/embed_file/embed_file.v b/vlib/v/embed_file/embed_file.v
index b6366f585a..271739c476 100644
--- a/vlib/v/embed_file/embed_file.v
+++ b/vlib/v/embed_file/embed_file.v
@@ -59,10 +59,10 @@ pub fn (original &EmbedFileData) to_bytes() []u8 {
 }
 
 pub fn (mut ed EmbedFileData) data() &u8 {
-	if !isnil(ed.uncompressed) {
+	if ed.uncompressed != unsafe { nil } {
 		return ed.uncompressed
 	}
-	if isnil(ed.uncompressed) && !isnil(ed.compressed) {
+	if ed.uncompressed == unsafe { nil } && ed.compressed != unsafe { nil } {
 		decoder := g_embed_file_decoders.decoders[ed.compression_type] or {
 			panic('EmbedFileData error: unknown compression of "$ed.path": "$ed.compression_type"')
 		}
diff --git a/vlib/v/fmt/fmt.v b/vlib/v/fmt/fmt.v
index 7010092693..8d68daeae5 100644
--- a/vlib/v/fmt/fmt.v
+++ b/vlib/v/fmt/fmt.v
@@ -1903,7 +1903,7 @@ pub fn (mut f Fmt) ident(node ast.Ident) {
 		f.write('_')
 	} else {
 		mut is_local := false
-		if !isnil(f.fn_scope) {
+		if f.fn_scope != unsafe { nil } {
 			if _ := f.fn_scope.find_var(node.name) {
 				is_local = true
 			}
diff --git a/vlib/v/gen/c/cgen.v b/vlib/v/gen/c/cgen.v
index 884b90a48c..b6af564cb2 100644
--- a/vlib/v/gen/c/cgen.v
+++ b/vlib/v/gen/c/cgen.v
@@ -2737,7 +2737,7 @@ fn (mut g Gen) trace_autofree(line string) {
 
 // fn (mut g Gen) autofree_scope_vars2(scope &ast.Scope, end_pos int) {
 fn (mut g Gen) autofree_scope_vars2(scope &ast.Scope, start_pos int, end_pos int, line_nr int, free_parent_scopes bool, stop_pos int) {
-	if isnil(scope) {
+	if scope == unsafe { nil } {
 		return
 	}
 	for _, obj in scope.objects {
@@ -2793,8 +2793,8 @@ fn (mut g Gen) autofree_scope_vars2(scope &ast.Scope, start_pos int, end_pos int
 	// return
 	// }
 	// ```
-	// if !isnil(scope.parent) && line_nr > 0 {
-	if free_parent_scopes && !isnil(scope.parent) && !scope.detached_from_parent
+	// if scope.parent != unsafe { nil } && line_nr > 0 {
+	if free_parent_scopes && scope.parent != unsafe { nil } && !scope.detached_from_parent
 		&& (stop_pos == -1 || scope.parent.start_pos >= stop_pos) {
 		g.trace_autofree('// af parent scope:')
 		g.autofree_scope_vars2(scope.parent, start_pos, end_pos, line_nr, true, stop_pos)
@@ -4239,7 +4239,7 @@ fn (mut g Gen) return_stmt(node ast.Return) {
 		ftyp := g.typ(node.types[0])
 		mut is_regular_option := ftyp == '_option'
 		if optional_none || is_regular_option || node.types[0] == ast.error_type_idx {
-			if !isnil(g.fn_decl) && g.fn_decl.is_test {
+			if g.fn_decl != unsafe { nil } && g.fn_decl.is_test {
 				test_error_var := g.new_tmp_var()
 				g.write('$ret_typ $test_error_var = ')
 				g.gen_optional_error(g.fn_decl.return_type, node.exprs[0])
@@ -4267,7 +4267,7 @@ fn (mut g Gen) return_stmt(node ast.Return) {
 		ftyp := g.typ(node.types[0])
 		mut is_regular_result := ftyp == c.result_name
 		if is_regular_result || node.types[0] == ast.error_type_idx {
-			if !isnil(g.fn_decl) && g.fn_decl.is_test {
+			if g.fn_decl != unsafe { nil } && g.fn_decl.is_test {
 				test_error_var := g.new_tmp_var()
 				g.write('$ret_typ $test_error_var = ')
 				g.gen_result_error(g.fn_decl.return_type, node.exprs[0])
@@ -5404,7 +5404,7 @@ fn (mut g Gen) or_block(var_name string, or_block ast.OrExpr, return_type ast.Ty
 		g.or_expr_return_type = ast.void_type
 	} else if or_block.kind == .propagate_result
 		|| (or_block.kind == .propagate_option && return_type.has_flag(.result)) {
-		if g.file.mod.name == 'main' && (isnil(g.fn_decl) || g.fn_decl.is_main) {
+		if g.file.mod.name == 'main' && (g.fn_decl == unsafe { nil } || g.fn_decl.is_main) {
 			// In main(), an `opt()!` call is sugar for `opt() or { panic(err) }`
 			err_msg := 'IError_name_table[${cvar_name}.err._typ]._method_msg(${cvar_name}.err._object)'
 			if g.pref.is_debug {
@@ -5413,7 +5413,7 @@ fn (mut g Gen) or_block(var_name string, or_block ast.OrExpr, return_type ast.Ty
 			} else {
 				g.writeln('\tpanic_result_not_set($err_msg);')
 			}
-		} else if !isnil(g.fn_decl) && g.fn_decl.is_test {
+		} else if g.fn_decl != unsafe { nil } && g.fn_decl.is_test {
 			g.gen_failing_error_propagation_for_test_fn(or_block, cvar_name)
 		} else {
 			// In ordinary functions, `opt()!` call is sugar for:
@@ -5433,7 +5433,7 @@ fn (mut g Gen) or_block(var_name string, or_block ast.OrExpr, return_type ast.Ty
 			}
 		}
 	} else if or_block.kind == .propagate_option {
-		if g.file.mod.name == 'main' && (isnil(g.fn_decl) || g.fn_decl.is_main) {
+		if g.file.mod.name == 'main' && (g.fn_decl == unsafe { nil } || g.fn_decl.is_main) {
 			// In main(), an `opt()?` call is sugar for `opt() or { panic(err) }`
 			err_msg := 'IError_name_table[${cvar_name}.err._typ]._method_msg(${cvar_name}.err._object)'
 			if g.pref.is_debug {
@@ -5442,7 +5442,7 @@ fn (mut g Gen) or_block(var_name string, or_block ast.OrExpr, return_type ast.Ty
 			} else {
 				g.writeln('\tpanic_optional_not_set( $err_msg );')
 			}
-		} else if !isnil(g.fn_decl) && g.fn_decl.is_test {
+		} else if g.fn_decl != unsafe { nil } && g.fn_decl.is_test {
 			g.gen_failing_error_propagation_for_test_fn(or_block, cvar_name)
 		} else {
 			// In ordinary functions, `opt()?` call is sugar for:
@@ -6078,7 +6078,7 @@ static inline __shared__$interface_name ${shared_fn_name}(__shared__$cctype* x)
 
 fn (mut g Gen) panic_debug_info(pos token.Pos) (int, string, string, string) {
 	paline := pos.line_nr + 1
-	if isnil(g.fn_decl) {
+	if g.fn_decl == unsafe { nil } {
 		return paline, '', 'main', 'C._vinit'
 	}
 	pafile := g.fn_decl.file.replace('\\', '/')
diff --git a/vlib/v/util/util.v b/vlib/v/util/util.v
index 2deee678f7..554698893e 100644
--- a/vlib/v/util/util.v
+++ b/vlib/v/util/util.v
@@ -295,7 +295,7 @@ mut:
 [unsafe]
 pub fn cached_read_source_file(path string) ?string {
 	mut static cache := &SourceCache(0)
-	if isnil(cache) {
+	if cache == unsafe { nil } {
 		cache = &SourceCache{}
 	}