// Copyright (c) 2019-2024 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license that can be found in the LICENSE file.
module checker

import v.ast

fn checker_table_fn_lookup(table &ast.Table, name string) (ast.Fn, bool) {
	if name !in table.fns {
		return ast.Fn{}, false
	}
	return unsafe { table.fns[name] }, true
}

@[inline]
fn (mut c Checker) is_nocopy_struct(typ_ ast.Type) bool {
	mut typ := c.unwrap_generic(typ_).clear_option_and_result()
	if typ == 0 || typ.is_ptr() {
		return false
	}
	mut sym := c.table.final_sym(typ)
	if sym.kind == .generic_inst && sym.info is ast.GenericInst {
		sym = c.table.sym(ast.new_type(sym.info.parent_idx))
	}
	return sym.info is ast.Struct && sym.info.attrs.contains('nocopy')
}

fn assign_expr_is_auto_deref(expr ast.Expr) bool {
	return expr.is_auto_deref_var()
}

fn (c &Checker) auto_deref_source_type_is_pointer(expr ast.Expr) bool {
	if expr !is ast.Ident || c.table.cur_fn == unsafe { nil } || !expr.is_auto_deref_var() {
		return false
	}
	ident := expr as ast.Ident
	for param in c.table.cur_fn.params {
		if param.name == ident.name {
			source_typ := if param.orig_typ != 0 { param.orig_typ } else { param.typ }
			return source_typ.is_any_kind_of_pointer()
		}
	}
	return false
}

fn (mut c Checker) smartcasted_assign_lhs_type(expr ast.Expr, fallback_type ast.Type) ast.Type {
	match expr {
		ast.Ident {
			if expr.obj is ast.Var && expr.obj.smartcasts.len > 0 {
				if expr.obj.orig_type.has_flag(.option) {
					return expr.obj.orig_type
				}
				if expr.obj.is_mut && expr.obj.orig_type != 0 {
					orig_sym := c.table.final_sym(expr.obj.orig_type)
					if orig_sym.kind == .sum_type {
						return expr.obj.orig_type
					}
				}
				return c.exposed_smartcast_type(expr.obj.orig_type, expr.obj.smartcasts.last(),
					expr.obj.is_mut)
			}
		}
		ast.SelectorExpr {
			if expr.expr_type != 0 {
				scope_field := expr.scope.find_struct_field(smartcast_selector_expr_str(expr),
					expr.expr_type, expr.field_name)
				if scope_field != unsafe { nil } && scope_field.smartcasts.len > 0 {
					if scope_field.orig_type.has_flag(.option) {
						return scope_field.orig_type
					}
					return c.exposed_smartcast_type(scope_field.orig_type,
						scope_field.smartcasts.last(), scope_field.is_mut)
				}
			}
		}
		else {}
	}

	return fallback_type
}

fn (mut c Checker) reset_option_assignment_smartcast(mut expr ast.Ident, left_type ast.Type) {
	if expr.scope == unsafe { nil } {
		return
	}
	if var := expr.scope.find_var(expr.name) {
		expr.scope.objects[expr.name] = ast.Var{
			...var
			typ:                     left_type
			pos:                     var.pos
			orig_type:               ast.no_type
			smartcasts:              []ast.Type{}
			is_assignment_smartcast: false
			is_unwrapped:            false
		}
	}
}

fn (mut c Checker) update_option_assignment_smartcast(mut expr ast.Expr, left_type ast.Type, right ast.Expr, right_type ast.Type) {
	if !left_type.has_flag(.option) {
		return
	}
	match mut expr {
		ast.Ident {
			mut original_pos := expr.pos
			if var := expr.scope.find_var(expr.name) {
				original_pos = var.pos
			}
			if right_type == ast.none_type || right_type == ast.nil_type
				|| right_type.has_flag(.option) || right.is_nil()
				|| (right is ast.UnsafeExpr && right.expr.is_nil()) {
				c.reset_option_assignment_smartcast(mut expr, left_type)
				return
			}
			c.smartcast(mut expr, left_type, left_type.clear_flag(.option), mut expr.scope, false,
				true, false, true)
			if mut scope_var := expr.scope.find_var(expr.name) {
				scope_var.is_assignment_smartcast = true
				scope_var.pos = original_pos
			}
		}
		else {}
	}
}

@[inline]
fn (c &Checker) disallow_implicit_int_to_f32_assign(got ast.Type, expected ast.Type) bool {
	got_type := c.table.unalias_num_type(got).clear_flags()
	expected_type := c.table.unalias_num_type(expected).clear_flags()
	return expected_type == ast.f32_type
		&& got_type in [ast.i32_type, ast.int_type, ast.i64_type, ast.isize_type, ast.u32_type, ast.u64_type, ast.usize_type]
}

// TODO: 980 line function
fn (mut c Checker) assign_stmt(mut node ast.AssignStmt) {
	prev_inside_assign := c.inside_assign
	c.inside_assign = true
	if node.attr.name != '' {
		c.assign_stmt_attr = node.attr.name
	} else {
		c.assign_stmt_attr = ''
	}
	c.expected_type = ast.none_type // TODO: a hack to make `x := if ... work`
	defer {
		c.expected_type = ast.void_type
		c.inside_assign = prev_inside_assign
	}
	is_decl := node.op == .decl_assign
	original_op := node.op
	mut right_first := node.right[0]
	node.left_types = []
	mut right_len := node.right.len
	mut right_first_type := ast.void_type
	old_recheck := c.inside_recheck

	// check if we are rechecking an already checked expression on generic rechecking
	c.inside_recheck = old_recheck || node.right_types.len > 0
	defer {
		c.inside_recheck = old_recheck
	}
	for i, mut right in node.right {
		if right in [ast.ArrayInit, ast.CallExpr, ast.ComptimeCall, ast.DumpExpr, ast.IfExpr,
			ast.LockExpr, ast.MapInit, ast.MatchExpr, ast.ParExpr, ast.SelectorExpr, ast.StructInit] {
			if right in [ast.ArrayInit, ast.IfExpr, ast.MapInit, ast.MatchExpr, ast.StructInit]
				&& node.left.len == node.right.len && !is_decl
				&& node.left[i] in [ast.Ident, ast.IndexExpr, ast.SelectorExpr]
				&& !node.left[i].is_blank_ident() {
				mut expr := node.left[i]
				old_is_index_assign := c.is_index_assign
				if expr is ast.IndexExpr {
					c.is_index_assign = true
				}
				c.expected_type = c.expr(mut expr)
				c.is_index_assign = old_is_index_assign
			}
			if is_decl && node.left[i] is ast.Ident && (node.left[i] as ast.Ident).is_mut()
				&& right is ast.StructInit && (right as ast.StructInit).is_anon {
				c.anon_struct_should_be_mut = true
			}
			mut right_type := c.expr(mut right)
			c.anon_struct_should_be_mut = false
			if right in [ast.CallExpr, ast.IfExpr, ast.LockExpr, ast.MatchExpr, ast.DumpExpr] {
				c.fail_if_unreadable(right, right_type, 'right-hand side of assignment')
			}
			if i == 0 {
				right_first_type = right_type
				node.right_types = [
					c.check_expr_option_or_result_call(right, right_first_type),
				]
			}
			if right_type != 0 {
				right_type_sym := c.table.sym(right_type)
				// fixed array returns an struct, but when assigning it must be the array type
				if right_type_sym.info is ast.ArrayFixed {
					right_type = c.cast_fixed_array_ret(right_type, right_type_sym)
				}
				if right_type_sym.kind == .multi_return {
					if node.right.len > 1 {
						c.error('cannot use multi-value ${right_type_sym.name} in single-value context',
							right.pos())
					}
					node.right_types = right_type_sym.mr_info().types.map(c.cast_fixed_array_ret(it,
						c.table.sym(it)))
					right_len = node.right_types.len
				}
			}
			if right_type == ast.void_type {
				right_len = 0
				if mut right is ast.IfExpr {
					last_branch := right.branches.last()
					last_stmts := last_branch.stmts.filter(it is ast.ExprStmt)
					if last_stmts.any((it as ast.ExprStmt).typ.has_flag(.generic)) {
						right_len = last_branch.stmts.len
						node.right_types = last_stmts.map((it as ast.ExprStmt).typ)
					}
				}
			}
		} else if mut right is ast.InfixExpr {
			if right.op == .arrow {
				c.error('cannot use `<-` on the right-hand side of an assignment, as it does not return any values',
					right.pos)
			} else if c.inside_recheck {
				if i < node.right_types.len {
					c.expected_type = node.right_types[i]
				}
				mut right_type := c.expr(mut right)
				if right_type != 0 {
					right_type_sym := c.table.sym(right_type)
					// fixed array returns an struct, but when assigning it must be the array type
					if right_type_sym.info is ast.ArrayFixed {
						right_type = c.cast_fixed_array_ret(right_type, right_type_sym)
					}
				}
				if i == 0 {
					right_first_type = right_type
					node.right_types = [
						c.check_expr_option_or_result_call(right, right_first_type),
					]
				}
			}
		}
		if mut right is ast.Ident {
			if right.is_mut {
				c.error('unexpected `mut` on right-hand side of assignment', right.mut_pos)
			}
		}
		if is_decl && mut right is ast.None {
			c.error('cannot assign a `none` value to a variable', right.pos)
		}
		// Handle `left_name := unsafe { none }`
		if mut right is ast.UnsafeExpr && right.expr is ast.None {
			c.error('cannot use `none` in `unsafe` blocks', right.expr.pos)
		}
		if mut right is ast.AnonFn {
			if right.decl.generic_names.len > 0 && (right.inherited_vars.len == 0
				|| !c.generic_anon_fn_can_use_current_context(right.decl.generic_names)) {
				c.error('cannot assign generic function to a variable', right.decl.pos)
			}
		}
	}
	if node.left.len != right_len {
		if right_len == 0 && right_first_type == ast.void_type {
			match right_first {
				ast.ArrayInit, ast.MapInit, ast.StructInit {
					if is_decl {
						for i, mut left in node.left {
							node.left_types << ast.void_type
							if mut left is ast.Ident {
								if mut left.info is ast.IdentVar {
									left.info.typ = ast.void_type
									if mut left.obj is ast.Var {
										left.obj.typ = ast.void_type
									}
								}
							}
							if i < node.right_types.len && node.right_types[i] == 0 {
								node.right_types[i] = ast.void_type
							}
						}
					}
					return
				}
				else {}
			}
		}
		if mut right_first is ast.CallExpr {
			if node.left_types.len > 0 && node.left_types[0] == ast.void_type {
				// If it's a void type, it's an unknown variable, already had an error earlier.
				return
			}
			str_variables := if node.left.len == 1 { 'variable' } else { 'variables' }
			str_values := if right_len == 1 { 'value' } else { 'values' }
			c.error('assignment mismatch: ${node.left.len} ${str_variables} but `${right_first.get_name()}()` returns ${right_len} ${str_values}',
				node.pos)
		} else if mut right_first is ast.ParExpr {
			mut right_next := right_first
			for {
				if mut right_next.expr is ast.CallExpr {
					if right_next.expr.return_type == ast.void_type {
						c.error('assignment mismatch: expected ${node.left.len} value(s) but `${right_next.expr.get_name()}()` returns ${right_len} value(s)',
							node.pos)
					}
					break
				} else if mut right_next.expr is ast.ParExpr {
					right_next = right_next.expr
				} else {
					break
				}
			}
		} else {
			str_variables := if node.left.len == 1 { 'variable' } else { 'variables' }
			str_values := if right_len == 1 { 'value' } else { 'values' }
			c.error('assignment mismatch: ${node.left.len} ${str_variables} ${right_len} ${str_values}',
				node.pos)
		}
		return
	}
	for i, mut left in node.left {
		if !is_decl {
			if left is ast.Ident {
				ident := left as ast.Ident
				c.clear_assert_autocast(ident.scope, ident.name)
			}
		}
		if mut left is ast.CallExpr {
			// ban `foo() = 10`
			if c.pref.is_vls {
				// in `vls` mode, code is incomplete, eval left also
				c.expr(mut left)
			} else {
				c.error('cannot call function `${left.name}()` on the left side of an assignment',
					left.pos)
			}
		} else if mut left is ast.PrefixExpr {
			// ban `*foo() = 10`
			if left.right is ast.CallExpr && left.op == .mul {
				c.error('cannot dereference a function call on the left side of an assignment, use a temporary variable',
					left.pos)
			}
		} else if mut left is ast.Ident && node.op == .decl_assign {
			if left.name in c.global_names {
				c.note('the global variable named `${left.name}` already exists', left.pos)
			}
		}
		is_blank_ident := left.is_blank_ident()
		mut left_type := ast.void_type
		mut var_option := false
		mut is_shared_re_assign := false
		if !is_decl && !is_blank_ident {
			if left in [ast.Ident, ast.SelectorExpr] {
				c.prevent_sum_type_unwrapping_once = true
			}
			if left is ast.IndexExpr {
				c.is_index_assign = true
			}
			left_type = c.expr(mut left)
			if left is ast.IndexExpr && left.index is ast.RangeExpr && !left.is_index_operator {
				c.error('cannot reassign using range expression on the left side of an assignment',
					left.pos)
			}
			left_type = c.smartcasted_assign_lhs_type(left, left_type)
			c.is_index_assign = false
			c.expected_type = c.unwrap_generic(left_type)
			is_shared_re_assign = left is ast.Ident && left.info is ast.IdentVar
				&& ((left.info as ast.IdentVar).share == .shared_t || left_type.has_flag(.shared_f))
		}

		if c.comptime.comptime_for_field_var != '' && mut left is ast.ComptimeSelector {
			if c.comptime.has_different_types && node.right[i].is_literal()
				&& !c.comptime.inside_comptime_if {
				c.error('mismatched types: check field type with \$if to avoid this problem',
					node.right[i].pos())
			}
			left_type = c.comptime.comptime_for_field_type
			c.expected_type = c.unwrap_generic(left_type)
		}
		if node.right_types.len < node.left.len { // first type or multi return types added above
			old_inside_ref_lit := c.inside_ref_lit
			if mut left is ast.Ident && left.info is ast.IdentVar {
				c.inside_ref_lit = c.inside_ref_lit || left.info.share == .shared_t
			}
			c.inside_decl_rhs = is_decl
			mut expr := node.right[i]
			if left is ast.Ident && left.is_mut() && expr is ast.StructInit && expr.is_anon {
				c.anon_struct_should_be_mut = true
				defer(fn) {
					c.anon_struct_should_be_mut = false
				}
			}
			right_type := c.expr(mut expr)
			c.inside_decl_rhs = false
			c.inside_ref_lit = old_inside_ref_lit
			if node.right_types.len == i {
				node.right_types << c.check_expr_option_or_result_call(node.right[i], right_type)
			}
		} else if c.inside_recheck && i < node.right.len {
			// Generic rechecks reuse the same AST nodes, so cached rhs types for
			// identifiers/selectors can be stale across concrete instantiations.
			needs_rhs_recheck := c.comptime.has_comptime_expr(node.right[i])
				|| node.right[i] in [ast.Ident, ast.SelectorExpr, ast.IndexExpr, ast.ComptimeSelector, ast.PrefixExpr, ast.CastExpr, ast.UnsafeExpr]
			if needs_rhs_recheck {
				mut expr := mut node.right[i]
				right_type := c.expr(mut expr)
				node.right_types[i] = c.check_expr_option_or_result_call(node.right[i], right_type)
			}
		}
		mut right := if i < node.right.len { node.right[i] } else { node.right[0] }
		mut right_type := node.right_types[i]
		right_pos := right.pos()
		left_pos := left.pos()
		if mut right is ast.Ident {
			// resolve shared right variable
			if right_type.has_flag(.shared_f) {
				if c.fail_if_unreadable(right, right_type, 'right-hand side of assignment') {
					return
				}
			}
			right_sym := c.table.sym(right_type)
			if right_sym.info is ast.Struct {
				if right_sym.info.generic_types.len > 0 {
					obj := right.scope.find_ptr(right.name)
					if obj != unsafe { nil } {
						match obj {
							ast.ConstField {
								right_type = obj.typ
							}
							ast.GlobalField {
								right_type = obj.typ
							}
							ast.Var {
								right_type = obj.typ
							}
							else {}
						}
					}
				}
			}
			if right.or_expr.kind in [.propagate_option, .block] {
				right_type = right_type.clear_flag(.option)
			}
		} else if right is ast.ComptimeSelector {
			if !(right as ast.ComptimeSelector).is_method {
				right_type = c.comptime.comptime_for_field_type
			}
		}
		if is_decl || is_shared_re_assign {
			// check generic struct init and return unwrap generic struct type
			if mut right is ast.StructInit {
				c.expr(mut right)
				if right.typ.has_flag(.generic) {
					right_type = right.typ
				}
			} else if mut right is ast.PrefixExpr {
				if right.op == .amp && right.right is ast.StructInit {
					right_type = c.expr(mut right)
				} else if right.op == .arrow {
					right_type = c.expr(mut right)
					right_type = c.cast_fixed_array_ret(right_type, c.table.sym(right_type))
				}
			} else if mut right is ast.Ident {
				if right.kind == .function {
					c.expr(mut right)
				}
			}
			if assign_expr_is_auto_deref(right) && right_type.is_ptr()
				&& !c.auto_deref_source_type_is_pointer(right) {
				left_type = ast.mktyp(right_type.deref())
			} else {
				left_type = ast.mktyp(right_type)
			}
			if left_type == ast.int_type {
				if mut right is ast.IntegerLiteral {
					val := right.val.i64()
					if overflows_i32(val) {
						c.error('overflow in implicit type `int`, use explicit type casting instead',
							right.pos)
					}
				}
			}
		} else {
			// Make sure the variable is mutable
			c.fail_if_immutable(mut left)

			if !is_blank_ident && !left_type.has_flag(.option) && right_type.has_flag(.option) {
				c.error('cannot assign an Option value to a non-option variable', right.pos())
			}
			// left_type = c.expr(left)
			// if right is ast.None && !left_type.has_flag(.option) {
			// 	println(left_type)
			// 	c.error('cannot assign a `none` value to a non-option variable', right.pos())
			// }
		}
		if !c.inside_unsafe && !is_blank_ident && node.op in [.decl_assign, .assign]
			&& left is ast.Ident && left.is_mut() {
			// check if right-side is a immutable reference
			c.fail_if_immutable_to_mutable(left_type, right_type, right)
		}
		if mut left is ast.Ident && left.info is ast.IdentVar && right is ast.Ident
			&& right.name in c.global_names {
			ident_var_info := left.info as ast.IdentVar
			if ident_var_info.share == .shared_t {
				c.error('cannot assign global variable to shared variable', right_pos)
			}
		}
		if right_type.is_ptr() && left_type.is_ptr() {
			if mut right is ast.Ident {
				c.fail_if_stack_struct_action_outside_unsafe(mut right, 'assigned')
			}
		}
		// Do not allow `a := 0; b := 0; a = &b`
		if !is_decl && left is ast.Ident && !is_blank_ident && !left_type.is_any_kind_of_pointer()
			&& right_type.is_any_kind_of_pointer() && !right_type.has_flag(.shared_f) {
			left_sym := c.table.sym(left_type)
			if left_sym.kind !in [.function, .array] {
				c.warn(
					'cannot assign a reference to a value (this will be an error soon) left=${c.table.type_str(left_type)} ${left_type.is_ptr()} ' +
					'right=${c.table.type_str(right_type)} ${right_type.is_any_kind_of_pointer()} ptr=${right_type.is_ptr()}',
					node.pos)
			}
		}
		node.left_types << left_type

		if right is ast.StructInit {
			right_sym := c.table.sym(right_type)
			c.check_any_type(right_type, right_sym, right_pos)
		}

		if left is ast.ParExpr && is_decl {
			c.error('parentheses are not supported on the left side of `:=`', left_pos)
		}
		left = left.remove_par()
		is_assign := node.op in [.assign, .decl_assign]
		match mut left {
			ast.Ident {
				if (is_decl || left.kind == .blank_ident) && left_type.is_ptr()
					&& right is ast.PrefixExpr {
					prefix_right := right as ast.PrefixExpr
					if prefix_right.right_type == ast.int_literal_type_idx
						&& prefix_right.right is ast.Ident {
						ident_right := prefix_right.right as ast.Ident
						if ident_right.obj is ast.ConstField {
							const_name := ident_right.name.all_after_last('.')
							const_val := (ident_right.obj as ast.ConstField).expr
							c.add_error_detail('Specify the type for the constant value. Example:')
							c.add_error_detail('         `const ${const_name} = int(${const_val})`')
							c.error('cannot assign a pointer to a constant with an integer literal value',
								ident_right.pos)
						}
					}
				}
				if left.kind == .blank_ident {
					if !is_decl && mut right is ast.None {
						c.error('cannot assign a `none` value to blank `_` identifier', right.pos)
					}
					left_type = right_type
					node.left_types[i] = right_type
					if !is_assign {
						c.error('cannot modify blank `_` identifier', left.pos)
					}
				} else if left.info !is ast.IdentVar {
					c.error('cannot assign to ${left.kind} `${left.name}`', left.pos)
				} else {
					if is_decl {
						c.check_valid_snake_case(left.name, 'variable name', left.pos)
						if reserved_type_names_chk.matches(left.name) {
							c.error('invalid use of reserved type `${left.name}` as a variable name',
								left.pos)
						}
					}
					if (is_decl || is_shared_re_assign) && right is ast.Nil && !c.inside_unsafe {
						// `x := unsafe { nil }` is allowed,
						// as well as:
						// `unsafe {
						//    x := nil
						//    println(x)
						// }`
						c.error('use of untyped nil in assignment (use `unsafe` | ${c.inside_unsafe})',
							right_pos)
					}
					mut ident_var_info := left.info as ast.IdentVar
					if ident_var_info.share == .shared_t || is_shared_re_assign {
						left_type = left_type.set_flag(.shared_f)
						if is_decl || is_shared_re_assign {
							if left_type.nr_muls() > 1 {
								c.error('shared cannot be multi level reference', left.pos)
							}
							left_type = left_type.set_nr_muls(1)
						}
					} else if left_type.has_flag(.shared_f) {
						left_type = left_type.clear_flag(.shared_f)
						if left_type.is_ptr() {
							left_type = left_type.deref()
						}
					}
					if ident_var_info.share == .atomic_t {
						left_type = left_type.set_flag(.atomic_f)
					}
					if ident_var_info.is_option {
						var_option = true
					}
					node.left_types[i] = left_type
					ident_var_info.typ = left_type
					left.info = ident_var_info
					if left_type != 0 {
						match mut left.obj {
							ast.Var {
								left.obj.typ = left_type
								if is_decl && node.left.len == node.right.len && i < node.right.len {
									left.obj.expr = node.right[i]
								}
								if is_decl && left.obj.generic_typ == 0
									&& (left_type.has_flag(.generic)
									|| c.type_has_unresolved_generic_parts(left_type)) {
									left.obj.generic_typ = left_type
									if left.scope != unsafe { nil } {
										if mut scope_var := left.scope.find_var(left.name) {
											scope_var.generic_typ = left_type
										}
									}
								}
								if left.obj.is_auto_deref {
									left.obj.is_used = true
								}
								if !left_type.is_ptr() {
									if c.table.sym(left_type).is_heap() {
										left.obj.is_auto_heap = true
									}
								}
								if left_type in ast.unsigned_integer_type_idxs {
									if mut right is ast.IntegerLiteral {
										if right.val[0] == `-` {
											c.error('cannot assign negative value to unsigned integer type',
												right.pos)
										}
									}
								}
								// flag the variable as comptime/generic related on its declaration
								if is_decl {
									c.change_flags_if_comptime_expr(mut left, right)
									if left.scope != unsafe { nil } {
										left.scope.update_var_type(left.name, left.obj.typ)
										if node.left.len == node.right.len && i < node.right.len {
											if mut scope_var := left.scope.find_var(left.name) {
												scope_var.expr = node.right[i]
											}
										}
									}
								}
							}
							ast.GlobalField {
								left.obj.typ = left_type
							}
							else {}
						}
					}
					if is_decl {
						full_name := '${left.mod}.${left.name}'
						scope_obj := c.file.global_scope.find_ptr(full_name)
						if scope_obj != unsafe { nil } {
							match scope_obj {
								ast.ConstField {
									c.warn('duplicate of a const name `${full_name}`', left.pos)
								}
								else {}
							}
						}
						if left.name == left.mod && left.name != 'main' {
							c.error('duplicate of a module name `${left.name}`', left.pos)
						}
						// Check if variable name is already registered as imported module symbol
						if c.check_import_sym_conflict(left.name) {
							c.error('duplicate of an import symbol `${left.name}`', left.pos)
						}
						c.check_module_name_conflict(left.name, left.pos)
					}
					if node.op == .assign && left_type.has_flag(.option) && right is ast.UnsafeExpr
						&& right.expr.is_nil() {
						c.error('cannot assign `nil` to option value', right_pos)
					}
				}
			}
			ast.PrefixExpr {
				// Do now allow `*x = y` outside `unsafe`
				if left.op == .mul {
					if !c.inside_unsafe && !c.pref.translated && !c.file.is_translated {
						c.error('modifying variables via dereferencing can only be done in `unsafe` blocks',
							node.pos)
					} else if mut left.right is ast.Ident {
						// mark `p` in `*p = val` as used:
						if mut left.right.obj is ast.Var {
							left.right.obj.is_used = true
						}
					}
				} else if left.op == .amp {
					c.error('cannot use a reference on the left side of `${node.op}`', left.pos)
				} else {
					c.error('cannot use `${left.op}` on the left of `${node.op}`', left.pos)
				}
				if is_decl {
					c.error('non-name on the left side of `:=`', left.pos)
				}
			}
			ast.SelectorExpr {
				if mut left.expr is ast.IndexExpr {
					if left.expr.is_index_operator {
						c.error('cannot assign through overloaded index expressions, use `[]=` instead',
							left.pos)
					} else if left.expr.is_map {
						left.expr.is_setter = true
					}
				}
				if left_type in ast.unsigned_integer_type_idxs {
					if mut right is ast.IntegerLiteral {
						if right.val[0] == `-` {
							c.error('cannot assign negative value to unsigned integer type',
								right.pos)
						}
					}
				}
				if left_type.has_flag(.option) && right is ast.UnsafeExpr && right.expr.is_nil() {
					c.error('cannot assign `nil` to option value', right_pos)
				}
			}
			else {
				if mut left is ast.IndexExpr {
					// eprintln('>>> left.is_setter: ${left.is_setter:10} | left.is_map: ${left.is_map:10} | left.is_array: ${left.is_array:10}')
					if (left.is_map || left.is_farray) && left.is_setter {
						left.recursive_mapset_is_setter(true)
					}
					right_type = c.type_resolver.get_type_or_default(right, right_type)
				}
				if mut left is ast.InfixExpr {
					c.error('cannot use infix expression on the left side of `${node.op}`',
						left.pos)
				}
				if is_decl && !c.pref.is_vls {
					c.error('non-name `${left}` on left side of `:=`', left.pos())
				}

				if node.op == .assign && (left.is_literal() || left is ast.StructInit) {
					c.error('non-name literal value `${left}` on left side of `=`', left.pos())
				}
			}
		}

		if mut left is ast.IndexExpr {
			if left.is_index_operator && node.op != .decl_assign {
				receiver_name := c.table.sym(c.unwrap_generic(left.left_type)).name
				if left.setter_arg_type == 0 {
					c.error('index assignment requires a `[]=` overload on type `${receiver_name}`',
						left.pos)
				} else if !left.left.is_lvalue() {
					c.error('cannot assign through overloaded index on a non-lvalue receiver',
						left.pos)
				}
				if node.op == .assign {
					left_type = left.setter_arg_type
				}
			}
		}
		left_type_unwrapped := c.unwrap_generic(ast.mktyp(left_type))
		right_type_unwrapped := c.unwrap_generic(right_type)
		if right_type_unwrapped == 0 {
			// right type was a generic `T`
			continue
		}
		if c.pref.translated || c.file.is_translated {
			// TODO: fix this in C2V instead, for example cast enums to int before using `|` on them.
			// TODO: replace all c.pref.translated checks with `$if !translated` for performance
			continue
		}
		if left_type_unwrapped == 0 {
			continue
		}
		left_sym := c.table.sym(left_type_unwrapped)
		right_sym := c.table.sym(right_type_unwrapped)

		if left_sym.kind == .array && !c.inside_unsafe && right_sym.kind == .array
			&& left is ast.Ident && !left.is_blank_ident() && right in [ast.Ident, ast.SelectorExpr]
			&& ((node.op == .decl_assign && left.is_mut) || node.op == .assign) {
			// Do not allow direct array assignments outside unsafe.
			// E.g.: `a2 = a1` wants `a2 = a1.clone()`, `a = val.arr_field` wants `a = val.arr_field.clone()`
			mut_str := if node.op == .decl_assign { 'mut ' } else { '' }
			c.error('use `${mut_str}array2 ${node.op.str()} array1.clone()` instead of `${mut_str}array2 ${node.op.str()} array1` (or use `unsafe`)',
				node.pos)
		}

		// Do not allow auto (de)reference in PrefixExpr
		// e.g. `*ptr1 = ptr2`
		if mut left is ast.PrefixExpr && left.op == .mul {
			if left_type.nr_muls() != right_type.nr_muls() && !left_type.is_voidptr()
				&& !right_type.is_voidptr() && right_type != ast.nil_type {
				r := right_sym.str_with_correct_nr_muls(right_type.nr_muls())
				l := left_sym.str_with_correct_nr_muls(left_type.nr_muls())
				c.error('cannot use `${r}` (right side) as `${l}` (left side) in assignment',
					node.pos)
			}
		}

		if left_sym.kind == .array && right_sym.kind == .array {
			right_info := right_sym.info as ast.Array
			right_elem_type := c.table.unaliased_type(right_info.elem_type)
			if node.op in [.decl_assign, .assign] {
				// Do not allow `mut arr := [&immutable_object]`
				if mut left is ast.Ident && right_elem_type.is_ptr() {
					if left.is_mut() || (left.obj is ast.Var && left.obj.is_mut) {
						if mut right is ast.ArrayInit && right.exprs.len > 0 {
							elem_expr := right.exprs[0]
							if elem_expr is ast.PrefixExpr && elem_expr.op == .amp {
								r := elem_expr.right
								if r is ast.Ident {
									obj := r.obj
									if obj is ast.Var && !obj.is_mut {
										c.warn('cannot add a reference to an immutable object to a mutable array',
											elem_expr.pos)
									}
								}
							}
						}
					}
				} else if mut left is ast.Ident && left.kind != .blank_ident {
					mut should_clone_slice := false
					right_notice_pos := right.pos()
					right_expr := right
					if right_expr is ast.IndexExpr {
						should_clone_slice = right_expr.left is ast.Ident
							&& right_expr.index is ast.RangeExpr
							&& (right_expr.left.is_mut() || left.is_mut()) && !c.inside_unsafe
					}
					if should_clone_slice {
						// `mut a := arr[..]` auto add clone() -> `mut a := arr[..].clone()`
						c.add_error_detail_with_pos('To silence this notice, use either an explicit `a[..].clone()`,
or use an explicit `unsafe{ a[..] }`, if you do not want a copy of the slice.',
							right_notice_pos)
						c.note('an implicit clone of the slice was done here', right_notice_pos)
						mut cloned_right := ast.CallExpr{
							name:           'clone'
							kind:           .clone
							left:           right
							left_type:      left_type
							is_method:      true
							receiver_type:  left_type
							return_type:    left_type
							scope:          c.fn_scope
							is_return_used: true
						}
						right_type = c.expr(mut cloned_right)
						right = cloned_right
						node.right[i] = cloned_right
					}
				}
			}
			if node.op == .assign {
				// `mut arr := [u8(1),2,3]`
				// `arr = [u8(4),5,6]`
				left_info := left_sym.info as ast.Array
				left_elem_type := c.table.unaliased_type(left_info.elem_type)
				if left_type_unwrapped.nr_muls() == right_type_unwrapped.nr_muls()
					&& left_info.nr_dims == right_info.nr_dims && left_elem_type == right_elem_type {
					continue
				}
			}
		}
		if left_sym.kind == .map && is_assign && right_sym.kind == .map && !c.inside_unsafe
			&& !left.is_blank_ident() && right.is_lvalue() && right !is ast.ComptimeSelector
			&& (!right_type.is_ptr() || (right is ast.Ident && assign_expr_is_auto_deref(right))) {
			// Do not allow `a = b`
			c.error('cannot copy map: call `move` or `clone` method (or use a reference)',
				right.pos())
		}
		if is_assign && !c.inside_unsafe && !left.is_blank_ident()
			&& c.is_nocopy_struct(left_type_unwrapped) && c.is_nocopy_struct(right_type_unwrapped)
			&& right !is ast.StructInit {
			c.error('cannot copy @[nocopy] struct: use a reference instead', right.pos())
		}
		if left_sym.kind == .function && right_sym.info is ast.FnType {
			return_sym := c.table.sym(right_sym.info.func.return_type)
			mut missing_fn_concrete_types := false
			if right is ast.Ident {
				ident := right as ast.Ident
				if ident.kind == .function {
					func, has_func := checker_table_fn_lookup(c.table, ident.name)
					if has_func {
						missing_fn_concrete_types = func.generic_names.len > 0
							&& ident.concrete_types.len == 0
					}
				}
			}
			if return_sym.kind == .placeholder {
				c.error('unknown return type: cannot assign `${right}` as a function variable',
					right.pos())
			} else if !missing_fn_concrete_types && right !is ast.AnonFn
				&& c.type_has_unresolved_generic_parts(right_sym.info.func.return_type) {
				c.error('cannot assign `${right}` as a generic function variable', right.pos())
			}
		}
		if left_sym.kind == .array_fixed && !c.inside_unsafe && is_assign
			&& right_sym.kind == .array_fixed && left is ast.Ident && !left.is_blank_ident()
			&& right is ast.Ident {
			if right_sym.info is ast.ArrayFixed {
				if right_sym.info.elem_type.is_ptr() {
					c.error('assignment from one fixed array to another with a pointer element type is prohibited outside of `unsafe`',
						node.pos)
				}
			}
		}
		if left_type.is_any_kind_of_pointer() && !assign_expr_is_auto_deref(left) {
			if !c.inside_unsafe && node.op !in [.assign, .decl_assign] {
				// ptr op=
				if !c.pref.translated && !c.file.is_translated {
					c.warn('pointer arithmetic is only allowed in `unsafe` blocks', node.pos)
				}
			}
			right_is_ptr := right_type.is_any_kind_of_pointer()
			if !left_type.has_flag(.shared_f) && !right_is_ptr && node.op == .assign
				&& right_type_unwrapped.is_number() {
				c.error('cannot assign to `${left}`: ' +
					c.expected_msg(right_type_unwrapped, left_type_unwrapped), right.pos())
			}
			if !right_sym.is_number() && !left_type.has_flag(.shared_f)
				&& (right is ast.StructInit || !right_is_ptr) {
				left_name := c.table.type_to_str(left_type_unwrapped)
				mut rtype := right_type_unwrapped
				if rtype.is_ptr() {
					rtype = rtype.deref()
				}
				right_name := c.table.type_to_str(rtype)
				if !(left_type.has_flag(.option) && right_type == ast.none_type) {
					c.error('mismatched types `${left_name}` and `${right_name}`', node.pos)
				}
			}
		}
		if mut left is ast.Ident && left.info is ast.IdentVar {
			if left.info.is_static {
				if right_sym.kind == .map {
					c.error('maps cannot be static', left.pos)
				} else if !right.is_constant() {
					c.error('cannot initialized static variable with non-constant value', left.pos)
				}
			}
		}
		// Single side check
		match node.op {
			.assign {} // No need to do single side check for =. But here put it first for speed.
			.plus_assign, .minus_assign {
				// allow literal values to auto deref var (e.g.`for mut v in values { v += 1.0 }`)
				left_deref := if assign_expr_is_auto_deref(left) && left_type.is_ptr() {
					left_type.deref()
				} else {
					left_type
				}
				if c.is_string_like_type(left_deref) {
					if node.op != .plus_assign {
						c.error('operator `${node.op}` not defined on left operand type `${left_sym.name}`',
							left.pos())
					}
					if node.op == .plus_assign && !c.is_string_concat_type(right_type) {
						c.error('invalid right operand: ${left_sym.name} ${node.op} ${right_sym.name}',
							right.pos())
					} else if node.op != .plus_assign && !c.is_string_like_type(right_type) {
						c.error('invalid right operand: ${left_sym.name} ${node.op} ${right_sym.name}',
							right.pos())
					}
				} else if !left_sym.is_number()
					&& left_sym.kind !in [.byteptr, .charptr, .struct, .alias] {
					c.error('operator `${node.op}` not defined on left operand type `${left_sym.name}`',
						left.pos())
				} else if !right_sym.is_number()
					&& left_sym.kind !in [.byteptr, .charptr, .struct, .alias] {
					c.error('invalid right operand: ${left_sym.name} ${node.op} ${right_sym.name}',
						right.pos())
				}
			}
			.mult_assign, .power_assign, .div_assign {
				if !left_sym.is_number() && !c.table.final_sym(left_type_unwrapped).is_int()
					&& left_sym.kind !in [.struct, .alias] {
					c.error('operator ${node.op.str()} not defined on left operand type `${left_sym.name}`',
						left.pos())
				} else if !right_sym.is_number() && !c.table.final_sym(left_type_unwrapped).is_int()
					&& left_sym.kind !in [.struct, .alias] {
					c.error('operator ${node.op.str()} not defined on right operand type `${right_sym.name}`',
						right.pos())
				}
			}
			.and_assign, .or_assign, .xor_assign {
				left_final_sym := c.table.final_sym(left_type_unwrapped)
				if left_final_sym.info is ast.Enum && left_final_sym.info.is_flag {
					// `@[flag]` tagged enums support compound bitwise assignment.
				} else if !left_sym.is_int() && !left_final_sym.is_int() {
					c.error('operator ${node.op.str()} not defined on left operand type `${left_sym.name}`',
						left.pos())
				} else if !right_sym.is_int() && !c.table.final_sym(right_type_unwrapped).is_int() {
					c.error('operator ${node.op.str()} not defined on right operand type `${right_sym.name}`',
						right.pos())
				}
			}
			.mod_assign, .left_shift_assign, .right_shift_assign {
				if !left_sym.is_int() && !c.table.final_sym(left_type_unwrapped).is_int() {
					c.error('operator ${node.op.str()} not defined on left operand type `${left_sym.name}`',
						left.pos())
				} else if !right_sym.is_int() && !c.table.final_sym(right_type_unwrapped).is_int() {
					c.error('operator ${node.op.str()} not defined on right operand type `${right_sym.name}`',
						right.pos())
				}
			}
			.boolean_and_assign, .boolean_or_assign {
				if c.table.final_sym(left_type_unwrapped).kind != .bool {
					c.error('operator ${node.op.str()} not defined on left operand type `${left_sym.name}`',
						left.pos())
				} else if c.table.final_sym(right_type_unwrapped).kind != .bool {
					c.error('operator ${node.op.str()} not defined on right operand type `${right_sym.name}`',
						right.pos())
				}
			}
			.unsigned_right_shift_assign {
				if node.left.len != 1 || node.right.len != 1 {
					c.error('unsupported operation: unable to lower expression for unsigned shift assignment.',
						node.pos)
				}
				mut modified_left_type := ast.void_type
				if !left_type.is_int() {
					c.error('invalid operation: shift on type `${c.table.sym(left_type).name}`',
						node.pos)
				} else if left_type.is_int_literal() {
					// int literal => i64
					modified_left_type = ast.u32_type
				} else if left_type.is_unsigned() {
					modified_left_type = left_type
				} else {
					// signed types => unsigned types
					unsigned_type := left_type.flip_signedness()
					if unsigned_type == ast.void_type {
						c.error('invalid operation: shift on type `${c.table.sym(left_type).name}`',
							node.pos)
					} else {
						modified_left_type = unsigned_type
					}
				}
				node = ast.AssignStmt{
					op:            .assign
					pos:           node.pos
					end_comments:  node.end_comments
					left:          node.left
					right:         [
						ast.Expr(ast.InfixExpr{
							left:       ast.CastExpr{
								expr:      node.left[0]
								typ:       modified_left_type
								typname:   c.table.type_str(modified_left_type)
								expr_type: left_type
								pos:       node.pos
							}
							op:         .right_shift
							right:      node.right[0]
							left_type:  modified_left_type
							right_type: right_type
							pos:        node.pos
						}),
					]
					left_types:    node.left_types
					right_types:   node.right_types
					is_static:     node.is_static
					is_simple:     node.is_simple
					has_cross_var: node.has_cross_var
				}
			}
			else {}
		}

		if node.op == .power_assign {
			c.markused_power_runtime_support()
		}
		if node.op in [.plus_assign, .minus_assign, .mod_assign, .mult_assign, .power_assign, .div_assign]
			&& (left_sym.kind == .alias || (left_sym.kind == .struct && right_sym.kind == .struct)) {
			left_name := c.table.type_to_str(left_type_unwrapped)
			right_name := c.table.type_to_str(right_type_unwrapped)
			parent_sym := c.table.final_sym(left_type_unwrapped)
			if left_sym.kind == .alias && right_sym.kind != .alias {
				if !parent_sym.is_primitive() {
					c.error('mismatched types `${left_name}` and `${right_name}`', node.pos)
				}
			}
			extracted_op := match node.op {
				.plus_assign { '+' }
				.minus_assign { '-' }
				.div_assign { '/' }
				.mod_assign { '%' }
				.mult_assign { '*' }
				.power_assign { '**' }
				else { 'unknown op' }
			}

			if left_sym.kind == .struct && (left_sym.info as ast.Struct).generic_types.len > 0 {
				continue
			}
			if method := left_sym.find_method_with_generic_parent(extracted_op) {
				c.mark_fn_decl_as_referenced(method.fkey())
				if method.return_type != left_type_unwrapped {
					c.error('operator `${extracted_op}` must return `${left_name}` to be used as an assignment operator',
						node.pos)
				}
				if right_sym.kind in [.alias, .struct]
					&& !c.check_same_type_ignoring_pointers(left_type_unwrapped, right_type_unwrapped) {
					c.error('cannot assign to `${left}`: expected `${left_name}`, not `${right_name}`',
						right.pos())
				}
			} else {
				if method := parent_sym.find_method_with_generic_parent(extracted_op) {
					c.mark_fn_decl_as_referenced(method.fkey())
					if parent_sym.kind == .alias
						&& (parent_sym.info as ast.Alias).parent_type != method.return_type {
						c.error('operator `${extracted_op}` must return `${left_name}` to be used as an assignment operator',
							node.pos)
					}
					if right_sym.kind in [.alias, .struct]
						&& !c.check_same_type_ignoring_pointers(left_type_unwrapped, right_type_unwrapped) {
						c.error('cannot assign to `${left}`: expected `${left_name}`, not `${right_name}`',
							right.pos())
					}
				} else {
					if !parent_sym.is_primitive() {
						if left_name == right_name {
							c.error('undefined operation `${left_name}` ${extracted_op} `${right_name}`',
								node.pos)
						} else {
							c.error('mismatched types `${left_name}` and `${right_name}`', node.pos)
						}
					}
				}
			}
		}
		if !is_blank_ident && right_sym.kind != .placeholder && left_sym.kind != .interface
			&& ((!right_type.has_flag(.generic) && !left_type.has_flag(.generic))
			|| right_sym.kind != left_sym.kind) {
			// Disallow `array = voidptr` assign
			if left_sym.kind in [.array, .array_fixed]
				&& (right_type_unwrapped.is_voidptr() || right.is_nil()) {
				left_str := c.table.type_to_str(left_type_unwrapped)
				right_str := c.table.type_to_str(right_type_unwrapped)
				c.error('cannot assign to `${left}`: expected `${left_str}`, not `${right_str}`',
					right.pos())
			}
			// Dual sides check (compatibility check)
			is_string_plus_assign := original_op == .plus_assign
				&& c.is_string_like_type(left_type_unwrapped)
				&& c.is_string_concat_type(right_type_unwrapped)
			assign_right_type := if
				original_op in [.left_shift_assign, .right_shift_assign, .unsigned_right_shift_assign]
				|| is_string_plus_assign {
				left_type_unwrapped
			} else {
				right_type_unwrapped
			}
			if original_op == .assign
				&& c.disallow_implicit_int_to_f32_assign(assign_right_type, left_type_unwrapped) {
				c.error('cannot assign to `${left}`: ${c.expected_msg(assign_right_type,
					left_type_unwrapped)}', right_pos)
			}
			c.check_expected(assign_right_type, left_type_unwrapped) or {
				if left.is_auto_deref_arg() && left_type.is_ptr() {
					left_deref := left_type.deref()
					right_deref := if right.is_pure_literal() {
						right.get_pure_type()
					} else if assign_expr_is_auto_deref(right) && right_type.is_ptr() {
						right_type.deref()
					} else {
						right_type
					}
					if left_deref.is_number() && right_deref.is_number() {
						continue
					}
				}
				// allow literal values to auto deref var (e.g.`for mut v in values { v = 1.0 }`)
				if assign_expr_is_auto_deref(left) || assign_expr_is_auto_deref(right) {
					left_deref := if assign_expr_is_auto_deref(left) && left_type.is_ptr() {
						left_type.deref()
					} else {
						left_type
					}
					right_deref := if right.is_pure_literal() {
						right.get_pure_type()
					} else if assign_expr_is_auto_deref(right) && right_type.is_ptr() {
						right_type.deref()
					} else {
						right_type
					}
					if c.check_types(right_deref, left_deref) {
						continue
					}
				}
				// allow for ptr += 2
				if left_type_unwrapped.is_ptr() && right_type_unwrapped.is_int()
					&& node.op in [.plus_assign, .minus_assign] {
					if !c.inside_unsafe {
						c.warn('pointer arithmetic is only allowed in `unsafe` blocks', node.pos)
					}
				} else {
					if c.comptime.comptime_for_field_var != '' && left is ast.ComptimeSelector {
						field_type := c.unwrap_generic(c.comptime.comptime_for_field_type)
						field_sym := c.table.sym(field_type)

						// allow `t.$(field.name) = 0` where `t.$(field.name)` is a enum
						if field_sym.kind == .enum && !right_type.is_int() {
							c.error('enums can only be assigned `int` values', right.pos())
						}
						// disallow invalid `t.$(field.name)` type assignment
						if !c.check_types(field_type, right_type) && !(c.inside_x_matches_type
							|| field_sym.kind == .enum) {
							c.error('cannot assign to `${ast.Expr(left)}`: ${c.expected_msg(right_type,
								field_type)}', right.pos())
						}
					} else {
						if right_type_unwrapped != ast.void_type {
							if !var_option || (var_option && right_type_unwrapped != ast.none_type) {
								if left_sym.kind == .array_fixed && right_sym.kind == .array
									&& right is ast.ArrayInit {
									c.add_error_detail('try adding `!` after the array literal, e.g.: `${left} = [...]!`')
									c.error('cannot assign to `${left}`: ${err.msg()}', right_pos)
								} else {
									c.error('cannot assign to `${left}`: ${err.msg()}', right_pos)
								}
							}
						}
					}
				}
			}
		}
		if left_sym.kind == .interface {
			if c.type_implements(right_type, left_type, right.pos()) {
				if !right_type.is_any_kind_of_pointer() && right_sym.kind != .interface
					&& !c.inside_unsafe {
					c.mark_as_referenced(mut &node.right[i], true)
				}
			}
		}
		if left_sym.info is ast.Struct && !left_sym.info.is_anon && right is ast.StructInit
			&& right.is_anon {
			c.error('cannot assign anonymous `struct` to a typed `struct`', right_pos)
		}
		if right_sym.kind == .alias && right_sym.name == 'byte' {
			c.error('byte is deprecated, use u8 instead', right.pos())
		}
		if original_op == .assign {
			c.update_option_assignment_smartcast(mut left, left_type, right, right_type)
		}
	}
	// this needs to run after the assign stmt left exprs have been run through checker
	// so that ident.obj is set
	// Check `x := &y` and `mut x := <-ch`
	if mut right_first is ast.PrefixExpr {
		mut right_node := right_first
		is_amp := right_first.op == .amp
		left_first := node.left[0]
		if left_first is ast.Ident {
			assigned_var := left_first
			mut is_shared := false
			if left_first.info is ast.IdentVar {
				is_shared = left_first.info.share == .shared_t
			}
			old_inside_ref_lit := c.inside_ref_lit
			c.inside_ref_lit = c.inside_ref_lit || right_node.op == .amp || is_shared
			c.expr(mut right_node.right)
			c.inside_ref_lit = old_inside_ref_lit
			if right_node.op == .amp {
				mut expr := right_node.right
				expr = expr.remove_par()
				if mut expr is ast.Ident {
					if mut expr.obj is ast.Var {
						v := expr.obj
						right_first_type = v.typ
					}
					if is_amp && !node.left[0].is_blank_ident() && expr.obj is ast.ConstField {
						c.error('cannot have mutable reference to const `${expr.name}`',
							right_node.pos)
					}
					if !c.inside_unsafe && assigned_var.is_mut() && !expr.is_mut() {
						c.error('`${expr.name}` is immutable, cannot have a mutable reference to it',
							right_node.pos)
					}
				}
			}
			if right_node.op == .arrow {
				if assigned_var.is_mut {
					right_sym := c.table.sym(right_first_type)
					if right_sym.kind == .chan {
						chan_info := right_sym.chan_info()
						if chan_info.elem_type.is_ptr() && !chan_info.is_mut {
							c.error('cannot have a mutable reference to object from `${right_sym.name}`',
								right_node.pos)
						}
					}
				}
			}
		}
	}
	if node.left_types.len != node.left.len {
		c.error('assign statement left type number mismatch', node.pos)
	}
}

// change_flags_if_comptime_expr changes the flags of the left variable if the right expression is comptime/generic expr
fn (mut c Checker) change_flags_if_comptime_expr(mut left ast.Ident, right ast.Expr) {
	if mut left.obj is ast.Var {
		if right is ast.ComptimeSelector {
			left.obj.typ = c.comptime.comptime_for_field_type
			if right.or_block.kind == .propagate_option {
				left.obj.typ = left.obj.typ.clear_flag(.option)
				left.obj.ct_type_unwrapped = true
			}
			left.obj.ct_type_var = .field_var
		} else if right is ast.InfixExpr {
			right_ct_var := c.comptime.get_ct_type_var(right.left)
			if right_ct_var != .no_comptime {
				left.obj.ct_type_var = right_ct_var
			}
		} else if right is ast.StructInit && right.unresolved && right.typ.has_flag(.generic) {
			left.obj.ct_type_var = .generic_param
		} else if right is ast.IndexExpr && c.comptime.is_comptime(right) {
			right_ct_var := c.comptime.get_ct_type_var(right.left)
			if right_ct_var != .no_comptime {
				left.obj.ct_type_var = right_ct_var
			}
		} else if right is ast.Ident && right.obj is ast.Var && right.or_expr.kind == .absent {
			right_obj_var := right.obj as ast.Var
			if right_obj_var.ct_type_var != .no_comptime {
				ctyp := c.type_resolver.get_type(right)
				if ctyp != ast.void_type {
					left.obj.ct_type_var = right_obj_var.ct_type_var
					left.obj.typ = ctyp
					if ctyp.has_flag(.generic) && c.unwrap_generic(ctyp).has_flag(.option) {
						left.obj.typ = left.obj.typ.set_flag(.option)
					}
				}
			}
		} else if right is ast.DumpExpr && right.expr is ast.ComptimeSelector {
			left.obj.ct_type_var = .field_var
			left.obj.typ = c.comptime.comptime_for_field_type
		} else if right is ast.CallExpr {
			if right.left_type != 0 && c.table.type_kind(right.left_type) == .array
				&& right.name == 'map' && right.args.len > 0 && right.args[0].expr is ast.AsCast
				&& right.args[0].expr.typ.has_flag(.generic) {
				left.obj.ct_type_var = .generic_var
			} else if left.obj.ct_type_var in [.generic_var, .no_comptime]
				&& c.table.cur_fn != unsafe { nil } && c.table.cur_fn.generic_names.len != 0
				&& !right.comptime_ret_val && c.type_resolver.is_generic_expr(right) {
				// mark variable as generic var because its type changes according to fn return generic resolution type
				left.obj.ct_type_var = .generic_var
			}
		} else if right is ast.PostfixExpr && right.op == .question {
			if right.expr is ast.Ident && right.expr.ct_expr {
				right_obj_var := right.expr.obj as ast.Var
				ctyp := c.type_resolver.get_type(right)
				if ctyp != ast.void_type {
					left.obj.ct_type_unwrapped = true
					left.obj.ct_type_var = right_obj_var.ct_type_var
					left.obj.typ = ctyp.clear_flag(.option)
				}
			} else if right.expr is ast.ComptimeSelector {
				left.obj.ct_type_unwrapped = true
				left.obj.ct_type_var = .field_var
				left.obj.typ = c.comptime.comptime_for_field_type.clear_flag(.option)
			}
		}
	}
}