diff --git a/cmd/tools/check_os_api_parity.v b/cmd/tools/check_os_api_parity.v
index 93c1051814..96f490ff8b 100644
--- a/cmd/tools/check_os_api_parity.v
+++ b/cmd/tools/check_os_api_parity.v
@@ -98,10 +98,9 @@ fn (app App) gen_api_for_module_in_os(mod_name, os_name string) string {
 	for f in b.parsed_files {
 		for s in f.stmts {
 			if s is ast.FnDecl {
-				fnd := s as ast.FnDecl
-				if fnd.is_pub {
-					fn_signature := fnd.stringify(b.table)
-					fn_mod := fnd.modname()
+				if it.is_pub {
+					fn_signature := it.stringify(b.table)
+					fn_mod := it.modname()
 					if fn_mod == mod_name {
 						fline := '${fn_mod}: $fn_signature'
 						res << fline
diff --git a/examples/lander.v b/examples/lander.v
index 9fb0d829cc..462feb1f55 100644
--- a/examples/lander.v
+++ b/examples/lander.v
@@ -33,8 +33,7 @@ fn wait() {
 
 fn (l Lander) land(w World) {
 	if w is Mars {
-		m := w as Mars
-		for m.dust_storm() {
+		for it.dust_storm() {
 			wait()
 		}
 	}
diff --git a/vlib/v/ast/str.v b/vlib/v/ast/str.v
index b9f2dc7e61..1a0ce139bf 100644
--- a/vlib/v/ast/str.v
+++ b/vlib/v/ast/str.v
@@ -279,8 +279,7 @@ pub fn (node Stmt) str() string {
 			mut out := ''
 			for i, left in it.left {
 				if left is Ident {
-					ident := left as Ident
-					var_info := ident.var_info()
+					var_info := it.var_info()
 					if var_info.is_mut {
 						out += 'mut '
 					}
diff --git a/vlib/v/builder/builder.v b/vlib/v/builder/builder.v
index 456789c0ac..545cacaf53 100644
--- a/vlib/v/builder/builder.v
+++ b/vlib/v/builder/builder.v
@@ -288,9 +288,8 @@ fn (b &Builder) print_warnings_and_errors() {
 			for file in b.parsed_files {
 				for stmt in file.stmts {
 					if stmt is ast.FnDecl {
-						f := stmt as ast.FnDecl
-						if f.name == fn_name {
-							fline := f.pos.line_nr
+						if it.name == fn_name {
+							fline := it.pos.line_nr
 							println('$file.path:$fline:')
 						}
 					}
diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 3b50292427..feb54a8fde 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -206,22 +206,18 @@ fn (mut c Checker) check_file_in_main(file ast.File) bool {
 				}
 			}
 			ast.TypeDecl {
-				// type_decl := stmt as ast.TypeDecl
 				if stmt is ast.AliasTypeDecl {
-					alias_decl := stmt as ast.AliasTypeDecl
-					if alias_decl.is_pub {
-						c.warn('type alias `$alias_decl.name` $no_pub_in_main_warning',
-							alias_decl.pos)
+					if it.is_pub {
+						c.warn('type alias `$it.name` $no_pub_in_main_warning',
+							it.pos)
 					}
 				} else if stmt is ast.SumTypeDecl {
-					sum_decl := stmt as ast.SumTypeDecl
-					if sum_decl.is_pub {
-						c.warn('sum type `$sum_decl.name` $no_pub_in_main_warning', sum_decl.pos)
+					if it.is_pub {
+						c.warn('sum type `$it.name` $no_pub_in_main_warning', it.pos)
 					}
 				} else if stmt is ast.FnTypeDecl {
-					fn_decl := stmt as ast.FnTypeDecl
-					if fn_decl.is_pub {
-						c.warn('type alias `$fn_decl.name` $no_pub_in_main_warning', fn_decl.pos)
+					if it.is_pub {
+						c.warn('type alias `$it.name` $no_pub_in_main_warning', it.pos)
 					}
 				}
 			}
@@ -995,7 +991,7 @@ pub fn (mut c Checker) call_fn(mut call_expr ast.CallExpr) table.Type {
 	if fn_name == 'json.encode' {
 	} else if fn_name == 'json.decode' {
 		expr := call_expr.args[0].expr
-		if !(expr is ast.Type) {
+		if expr !is ast.Type {
 			typ := typeof(expr)
 			c.error('json.decode: first argument needs to be a type, got `$typ`', call_expr.pos)
 			return table.void_type
@@ -1270,26 +1266,25 @@ fn (mut c Checker) type_implements(typ, inter_typ table.Type, pos token.Position
 // return the actual type of the expression, once the optional is handled
 pub fn (mut c Checker) check_expr_opt_call(expr ast.Expr, ret_type table.Type) table.Type {
 	if expr is ast.CallExpr {
-		call_expr := expr as ast.CallExpr
-		if call_expr.return_type.has_flag(.optional) {
-			if call_expr.or_block.kind == .absent {
+		if it.return_type.has_flag(.optional) {
+			if it.or_block.kind == .absent {
 				if ret_type != table.void_type {
-					c.error('${call_expr.name}() returns an option, but you missed to add an `or {}` block to it',
-						call_expr.pos)
+					c.error('${it.name}() returns an option, but you missed to add an `or {}` block to it',
+						it.pos)
 				}
 			} else {
-				c.check_or_expr(call_expr.or_block, ret_type)
+				c.check_or_expr(it.or_block, ret_type)
 			}
 			// remove optional flag
 			// return ret_type.clear_flag(.optional)
 			// TODO: currently unwrapped in assign, would need to refactor assign to unwrap here
 			return ret_type
-		} else if call_expr.or_block.kind == .block {
-			c.error('unexpected `or` block, the function `$call_expr.name` does not return an optional',
-				call_expr.pos)
-		} else if call_expr.or_block.kind == .propagate {
-			c.error('unexpected `?`, the function `$call_expr.name`, does not return an optional',
-				call_expr.pos)
+		} else if it.or_block.kind == .block {
+			c.error('unexpected `or` block, the function `$it.name` does not return an optional',
+				it.pos)
+		} else if it.or_block.kind == .propagate {
+			c.error('unexpected `?`, the function `$it.name`, does not return an optional',
+				it.pos)
 		}
 	}
 	return ret_type
@@ -1527,8 +1522,7 @@ pub fn (mut c Checker) assign_stmt(mut assign_stmt ast.AssignStmt) {
 	}
 	if assign_stmt.left.len != right_len {
 		if right_first is ast.CallExpr {
-			call_expr := assign_stmt.right[0] as ast.CallExpr
-			c.error('assignment mismatch: $assign_stmt.left.len variable(s) but `${call_expr.name}()` returns $right_len value(s)',
+			c.error('assignment mismatch: $assign_stmt.left.len variable(s) but `${it.name}()` returns $right_len value(s)',
 				assign_stmt.pos)
 		} else {
 			c.error('assignment mismatch: $assign_stmt.left.len variable(s) $right_len value(s)',
@@ -1982,7 +1976,7 @@ fn (mut c Checker) stmt(node ast.Stmt) {
 			c.check_valid_snake_case(node.name, 'global name', node.pos)
 		}
 		ast.GoStmt {
-			if !(node.call_expr is ast.CallExpr) {
+			if node.call_expr !is ast.CallExpr {
 				c.error('expression in `go` must be a function call', node.call_expr.position())
 			}
 			c.expr(node.call_expr)
@@ -2803,7 +2797,7 @@ pub fn (mut c Checker) enum_val(mut node ast.EnumVal) table.Type {
 		c.error('expected type is not an enum', node.pos)
 		return table.void_type
 	}
-	if !(typ_sym.info is table.Enum) {
+	if typ_sym.info !is table.Enum {
 		c.error('not an enum', node.pos)
 		return table.void_type
 	}
diff --git a/vlib/v/doc/doc.v b/vlib/v/doc/doc.v
index 7f7831f05d..859e1fef85 100644
--- a/vlib/v/doc/doc.v
+++ b/vlib/v/doc/doc.v
@@ -45,8 +45,7 @@ pub fn merge_comments(stmts []ast.Stmt) string {
 	mut res := []string{}
 	for s in stmts {
 		if s is ast.Comment {
-			c  := s as ast.Comment
-			res << c.text.trim_left('|')
+			res << it.text.trim_left('|')
 		}
 	}
 	return res.join('\n')
@@ -375,12 +374,11 @@ fn (mut d Doc) generate() ?Doc {
 				continue
 			}
 			if stmt is ast.FnDecl {
-				fnd := stmt as ast.FnDecl
-				if fnd.is_deprecated {
+				if it.is_deprecated {
 					continue
 				}
-				if fnd.receiver.typ != 0 {
-					node.attrs['parent'] = d.fmt.type_to_str(fnd.receiver.typ).trim_left('&')
+				if it.receiver.typ != 0 {
+					node.attrs['parent'] = d.fmt.type_to_str(it.receiver.typ).trim_left('&')
 					p_idx := d.contents.index_by_name(node.attrs['parent'])
 					if p_idx == -1 && node.attrs['parent'] != 'void' {
 						d.contents << DocNode{
@@ -405,7 +403,7 @@ fn (mut d Doc) generate() ?Doc {
 				ast.InterfaceDecl { node.attrs['category'] = 'Interfaces' }
 				ast.StructDecl { node.attrs['category'] = 'Structs' }
 				ast.TypeDecl { node.attrs['category'] = 'Typedefs' }
-				ast.FnDecl { 
+				ast.FnDecl {
 					node.attrs['category'] = if node.attrs['parent'] in ['void', ''] || !node.attrs.exists('parent') {
 						'Functions'
 					} else {
diff --git a/vlib/v/fmt/fmt.v b/vlib/v/fmt/fmt.v
index 2ac33269ae..a3f02f40b7 100644
--- a/vlib/v/fmt/fmt.v
+++ b/vlib/v/fmt/fmt.v
@@ -246,8 +246,7 @@ pub fn (mut f Fmt) stmt(node ast.Stmt) {
 		ast.AssignStmt {
 			for i, left in node.left {
 				if left is ast.Ident {
-					ident := left as ast.Ident
-					var_info := ident.var_info()
+					var_info := it.var_info()
 					if var_info.is_mut {
 						f.write('mut ')
 					}
@@ -661,9 +660,8 @@ pub fn (mut f Fmt) prefix_expr_cast_expr(fexpr ast.Expr) {
 	mut is_pe_amp_ce := false
 	mut ce := ast.CastExpr{}
 	if fexpr is ast.PrefixExpr {
-		pe := fexpr as ast.PrefixExpr
-		if pe.right is ast.CastExpr && pe.op == .amp {
-			ce = pe.right as ast.CastExpr
+		if it.right is ast.CastExpr && it.op == .amp {
+			ce = it.right as ast.CastExpr
 			ce.typname = f.table.get_type_symbol(ce.typ).name
 			is_pe_amp_ce = true
 			f.expr(ce)
@@ -1323,8 +1321,7 @@ pub fn (mut f Fmt) match_expr(it ast.MatchExpr) {
 		stmt := branch.stmts[0]
 		if stmt is ast.ExprStmt {
 			// If expressions inside match branches can't be one a single line
-			expr_stmt := stmt as ast.ExprStmt
-			if !expr_is_single_line(expr_stmt.expr) {
+			if !expr_is_single_line(it.expr) {
 				single_line = false
 				break
 			}
diff --git a/vlib/v/gen/cgen.v b/vlib/v/gen/cgen.v
index d9893d201f..092591e9e7 100644
--- a/vlib/v/gen/cgen.v
+++ b/vlib/v/gen/cgen.v
@@ -1205,7 +1205,7 @@ fn (mut g Gen) gen_assign_stmt(assign_stmt ast.AssignStmt) {
 		mut blank_assign := false
 		mut ident := ast.Ident{}
 		if left is ast.Ident {
-			ident = left as ast.Ident
+			ident = it
 			// id_info := ident.var_info()
 			// var_type = id_info.typ
 			blank_assign = ident.kind == .blank_ident
@@ -1382,10 +1382,9 @@ fn (mut g Gen) gen_cross_tmp_variable(left []ast.Expr, val ast.Expr) {
 			mut has_var := false
 			for lx in left {
 				if lx is ast.Ident {
-					ident := lx as ast.Ident
-					if val.name == ident.name {
+					if val.name == it.name {
 						g.write('_var_')
-						g.write(ident.pos.pos.str())
+						g.write(it.pos.pos.str())
 						has_var = true
 						break
 					}
diff --git a/vlib/v/gen/comptime.v b/vlib/v/gen/comptime.v
index 7ba9e222f3..758e8a0024 100644
--- a/vlib/v/gen/comptime.v
+++ b/vlib/v/gen/comptime.v
@@ -11,11 +11,10 @@ fn (g &Gen) comptime_call(node ast.ComptimeCall) {
 	if node.is_vweb {
 		for stmt in node.vweb_tmpl.stmts {
 			if stmt is ast.FnDecl {
-				fn_decl := stmt as ast.FnDecl
 				// insert stmts from vweb_tmpl fn
-				if fn_decl.name.starts_with('main.vweb_tmpl') {
+				if it.name.starts_with('main.vweb_tmpl') {
 					g.inside_vweb_tmpl = true
-					g.stmts(fn_decl.stmts)
+					g.stmts(it.stmts)
 					g.inside_vweb_tmpl = false
 					break
 				}
diff --git a/vlib/v/gen/js/js.v b/vlib/v/gen/js/js.v
index 8eb01b1849..1a2f8b5e51 100644
--- a/vlib/v/gen/js/js.v
+++ b/vlib/v/gen/js/js.v
@@ -686,9 +686,8 @@ fn (mut g JsGen) gen_assign_stmt(stmt ast.AssignStmt) {
 			val := stmt.right[i]
 			mut is_mut := false
 			if left is ast.Ident {
-				ident := left as ast.Ident
-				is_mut = ident.is_mut
-				if ident.kind == .blank_ident || ident.name in ['', '_'] {
+				is_mut = it.is_mut
+				if it.kind == .blank_ident || it.name in ['', '_'] {
 					tmp_var := g.new_tmp_var()
 					// TODO: Can the tmp_var declaration be omitted?
 					g.write('const $tmp_var = ')
@@ -1254,12 +1253,12 @@ fn (mut g JsGen) gen_if_expr(node ast.IfExpr) {
 	}
 }
 
-fn (mut g JsGen) gen_index_expr(it ast.IndexExpr) {
-	left_typ := g.table.get_type_symbol(it.left_type)
+fn (mut g JsGen) gen_index_expr(expr ast.IndexExpr) {
+	left_typ := g.table.get_type_symbol(expr.left_type)
 	// TODO: Handle splice setting if it's implemented
-	if it.index is ast.RangeExpr {
-		range := it.index as ast.RangeExpr
-		g.expr(it.left)
+	if expr.index is ast.RangeExpr {
+		range := expr.index as ast.RangeExpr
+		g.expr(expr.left)
 		g.write('.slice(')
 		if range.has_low {
 			g.expr(range.low)
@@ -1270,35 +1269,35 @@ fn (mut g JsGen) gen_index_expr(it ast.IndexExpr) {
 		if range.has_high {
 			g.expr(range.high)
 		} else {
-			g.expr(it.left)
+			g.expr(expr.left)
 			g.write('.length')
 		}
 		g.write(')')
 	} else if left_typ.kind == .map {
-		g.expr(it.left)
-		if it.is_setter {
+		g.expr(expr.left)
+		if expr.is_setter {
 			g.inside_map_set = true
 			g.write('.set(')
 		} else {
 			g.write('.get(')
 		}
-		g.expr(it.index)
-		if !it.is_setter { g.write(')') }
+		g.expr(expr.index)
+		if !expr.is_setter { g.write(')') }
 	} else if left_typ.kind == .string {
-		if it.is_setter {
+		if expr.is_setter {
 			// TODO: What's the best way to do this?
 			// 'string'[3] = `o`
 		} else {
-			g.expr(it.left)
+			g.expr(expr.left)
 			g.write('.charCodeAt(')
-			g.expr(it.index)
+			g.expr(expr.index)
 			g.write(')')
 		}
 	} else {
 		// TODO Does this cover all cases?
-		g.expr(it.left)
+		g.expr(expr.left)
 		g.write('[')
-		g.expr(it.index)
+		g.expr(expr.index)
 		g.write(']')
 	}
 }
diff --git a/vlib/v/gen/json.v b/vlib/v/gen/json.v
index e19b4dceaa..22d39e4b82 100644
--- a/vlib/v/gen/json.v
+++ b/vlib/v/gen/json.v
@@ -75,7 +75,7 @@ $enc_fn_dec {
 		// enc += g.encode_array(t)
 	} else {
 		// Structs. Range through fields
-		if !(sym.info is table.Struct) {
+		if sym.info !is table.Struct {
 			verror('json: $sym.name is not struct')
 		}
 		info := sym.info as table.Struct
@@ -111,7 +111,7 @@ $enc_fn_dec {
 			mut enc_name := js_enc_name(field_type)
 			if g.table.get_type_symbol(field.typ).kind == .enum_ {
 				enc.writeln('\tcJSON_AddItemToObject(o, "$name", json__encode_u64(val.${c_name(field.name)}));')
-				
+
 			} else {
 				enc.writeln('\tcJSON_AddItemToObject(o, "$name", ${enc_name}(val.${c_name(field.name)}));')
 			}
diff --git a/vlib/v/gen/x64/gen.v b/vlib/v/gen/x64/gen.v
index 4919ba7cb0..ee8a8159ce 100644
--- a/vlib/v/gen/x64/gen.v
+++ b/vlib/v/gen/x64/gen.v
@@ -840,7 +840,7 @@ fn (mut g Gen) fn_decl(node ast.FnDecl) {
 }
 
 fn (mut g Gen) postfix_expr(node ast.PostfixExpr) {
-	if !(node.expr is ast.Ident) {
+	if node.expr !is ast.Ident {
 		return
 	}
 	ident := node.expr as ast.Ident
diff --git a/vlib/v/parser/assign.v b/vlib/v/parser/assign.v
index e34b96bc73..0ade268899 100644
--- a/vlib/v/parser/assign.v
+++ b/vlib/v/parser/assign.v
@@ -15,8 +15,7 @@ fn (mut p Parser) check_undefined_variables(exprs []ast.Expr, val ast.Expr) {
 		ast.Ident {
 			for expr in exprs {
 				if expr is ast.Ident {
-					ident := expr as ast.Ident
-					if ident.name == val.name {
+					if it.name == val.name {
 						p.error_with_pos('undefined variable: `$val.name`', val.pos)
 					}
 				}
@@ -50,8 +49,7 @@ fn (mut p Parser) check_cross_variables(exprs []ast.Expr, val ast.Expr) bool {
 		ast.Ident {
 			for expr in exprs {
 				if expr is ast.Ident {
-					ident := expr as ast.Ident
-					if ident.name == val_.name {
+					if it.name == val_.name {
 						return true
 					}
 				}
diff --git a/vlib/v/parser/comptime.v b/vlib/v/parser/comptime.v
index 2f0d3e793d..19df33dbe7 100644
--- a/vlib/v/parser/comptime.v
+++ b/vlib/v/parser/comptime.v
@@ -134,7 +134,7 @@ fn (mut p Parser) vweb() ast.ComptimeCall {
 				tmpl_scope := file.scope.innermost(fn_decl.body_pos.pos)
 				for _, obj in p.scope.objects {
 					if obj is ast.Var {
-						mut v := obj as ast.Var
+						mut v := it
 						v.pos = fn_decl.body_pos
 						tmpl_scope.register(v.name, *v)
 						// set the controller action var to used
diff --git a/vlib/v/parser/fn.v b/vlib/v/parser/fn.v
index c0fc44c91f..9e7bf4f70f 100644
--- a/vlib/v/parser/fn.v
+++ b/vlib/v/parser/fn.v
@@ -563,8 +563,7 @@ fn (mut p Parser) fn_redefinition_error(name string) {
 fn have_fn_main(stmts []ast.Stmt) bool {
 	for stmt in stmts {
 		if stmt is ast.FnDecl {
-			f := stmt as ast.FnDecl
-			if f.name == 'main.main' && f.mod == 'main' {
+			if it.name == 'main.main' && it.mod == 'main' {
 				return true
 			}
 		}