378 lines
16 KiB
Rust
378 lines
16 KiB
Rust
use crate::typecheck::typedef::TypeEnum;
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use super::type_inferencer::Inferencer;
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use super::typedef::Type;
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use nac3parser::ast::{self, Constant, Expr, ExprKind, Operator::{LShift, RShift}, Stmt, StmtKind, StrRef};
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use std::{collections::HashSet, iter::once};
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impl<'a> Inferencer<'a> {
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fn should_have_value(&mut self, expr: &Expr<Option<Type>>) -> Result<(), HashSet<String>> {
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if matches!(expr.custom, Some(ty) if self.unifier.unioned(ty, self.primitives.none)) {
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Err(HashSet::from([
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format!("Error at {}: cannot have value none", expr.location),
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]))
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} else {
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Ok(())
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}
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}
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fn check_pattern(
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&mut self,
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pattern: &Expr<Option<Type>>,
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defined_identifiers: &mut HashSet<StrRef>,
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) -> Result<(), HashSet<String>> {
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match &pattern.node {
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ExprKind::Name { id, .. } if id == &"none".into() => Err(HashSet::from([
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format!("cannot assign to a `none` (at {})", pattern.location),
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])),
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ExprKind::Name { id, .. } => {
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if !defined_identifiers.contains(id) {
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defined_identifiers.insert(*id);
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}
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self.should_have_value(pattern)?;
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Ok(())
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}
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ExprKind::Tuple { elts, .. } => {
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for elt in elts {
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self.check_pattern(elt, defined_identifiers)?;
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self.should_have_value(elt)?;
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}
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Ok(())
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}
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ExprKind::Subscript { value, slice, .. } => {
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self.check_expr(value, defined_identifiers)?;
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self.should_have_value(value)?;
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self.check_expr(slice, defined_identifiers)?;
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if let TypeEnum::TTuple { .. } = &*self.unifier.get_ty(value.custom.unwrap()) {
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return Err(HashSet::from([
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format!(
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"Error at {}: cannot assign to tuple element",
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value.location
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),
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]))
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}
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Ok(())
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}
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ExprKind::Constant { .. } => {
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Err(HashSet::from([
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format!("cannot assign to a constant (at {})", pattern.location),
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]))
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}
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_ => self.check_expr(pattern, defined_identifiers),
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}
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}
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fn check_expr(
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&mut self,
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expr: &Expr<Option<Type>>,
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defined_identifiers: &mut HashSet<StrRef>,
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) -> Result<(), HashSet<String>> {
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// there are some cases where the custom field is None
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if let Some(ty) = &expr.custom {
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if !matches!(&expr.node, ExprKind::Constant { value: Constant::Ellipsis, .. }) && !self.unifier.is_concrete(*ty, &self.function_data.bound_variables) {
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return Err(HashSet::from([
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format!(
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"expected concrete type at {} but got {}",
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expr.location,
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self.unifier.get_ty(*ty).get_type_name()
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)
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]))
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}
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}
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match &expr.node {
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ExprKind::Name { id, .. } => {
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if id == &"none".into() {
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return Ok(());
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}
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self.should_have_value(expr)?;
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if !defined_identifiers.contains(id) {
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match self.function_data.resolver.get_symbol_type(
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self.unifier,
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&self.top_level.definitions.read(),
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self.primitives,
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*id,
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) {
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Ok(_) => {
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self.defined_identifiers.insert(*id);
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}
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Err(e) => {
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return Err(HashSet::from([
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format!(
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"type error at identifier `{}` ({}) at {}",
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id, e, expr.location
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)
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]))
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}
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}
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}
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}
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ExprKind::List { elts, .. }
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| ExprKind::Tuple { elts, .. }
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| ExprKind::BoolOp { values: elts, .. } => {
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for elt in elts {
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self.check_expr(elt, defined_identifiers)?;
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self.should_have_value(elt)?;
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}
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}
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ExprKind::Attribute { value, .. } => {
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self.check_expr(value, defined_identifiers)?;
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self.should_have_value(value)?;
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}
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ExprKind::BinOp { left, op, right } => {
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self.check_expr(left, defined_identifiers)?;
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self.check_expr(right, defined_identifiers)?;
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self.should_have_value(left)?;
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self.should_have_value(right)?;
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// Check whether a bitwise shift has a negative RHS constant value
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if *op == LShift || *op == RShift {
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if let ExprKind::Constant { value, .. } = &right.node {
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let Constant::Int(rhs_val) = value else {
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unreachable!()
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};
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if *rhs_val < 0 {
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return Err(HashSet::from([
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format!(
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"shift count is negative at {}",
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right.location
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),
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]))
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}
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}
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}
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}
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ExprKind::UnaryOp { operand, .. } => {
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self.check_expr(operand, defined_identifiers)?;
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self.should_have_value(operand)?;
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}
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ExprKind::Compare { left, comparators, .. } => {
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for elt in once(left.as_ref()).chain(comparators.iter()) {
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self.check_expr(elt, defined_identifiers)?;
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self.should_have_value(elt)?;
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}
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}
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ExprKind::Subscript { value, slice, .. } => {
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self.should_have_value(value)?;
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self.check_expr(value, defined_identifiers)?;
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self.check_expr(slice, defined_identifiers)?;
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}
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ExprKind::IfExp { test, body, orelse } => {
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self.check_expr(test, defined_identifiers)?;
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self.check_expr(body, defined_identifiers)?;
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self.check_expr(orelse, defined_identifiers)?;
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}
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ExprKind::Slice { lower, upper, step } => {
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for elt in [lower.as_ref(), upper.as_ref(), step.as_ref()].iter().flatten() {
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self.should_have_value(elt)?;
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self.check_expr(elt, defined_identifiers)?;
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}
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}
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ExprKind::Lambda { args, body } => {
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let mut defined_identifiers = defined_identifiers.clone();
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for arg in &args.args {
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// TODO: should we check the types here?
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if !defined_identifiers.contains(&arg.node.arg) {
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defined_identifiers.insert(arg.node.arg);
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}
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}
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self.check_expr(body, &mut defined_identifiers)?;
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}
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ExprKind::ListComp { elt, generators, .. } => {
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// in our type inference stage, we already make sure that there is only 1 generator
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let ast::Comprehension { target, iter, ifs, .. } = &generators[0];
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self.check_expr(iter, defined_identifiers)?;
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self.should_have_value(iter)?;
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let mut defined_identifiers = defined_identifiers.clone();
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self.check_pattern(target, &mut defined_identifiers)?;
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self.should_have_value(target)?;
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for term in once(elt.as_ref()).chain(ifs.iter()) {
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self.check_expr(term, &mut defined_identifiers)?;
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self.should_have_value(term)?;
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}
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}
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ExprKind::Call { func, args, keywords } => {
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for expr in once(func.as_ref())
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.chain(args.iter())
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.chain(keywords.iter().map(|v| v.node.value.as_ref()))
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{
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self.check_expr(expr, defined_identifiers)?;
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self.should_have_value(expr)?;
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}
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}
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ExprKind::Constant { .. } => {}
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_ => {
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unimplemented!()
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}
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}
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Ok(())
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}
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/// Check that the return value is a non-`alloca` type, effectively only allowing primitive types.
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///
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/// This is a workaround preventing the caller from using a variable `alloca`-ed in the body, which
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/// is freed when the function returns.
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fn check_return_value_ty(&mut self, ret_ty: Type) -> bool {
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match &*self.unifier.get_ty_immutable(ret_ty) {
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TypeEnum::TObj { .. } => {
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[
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self.primitives.int32,
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self.primitives.int64,
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self.primitives.uint32,
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self.primitives.uint64,
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self.primitives.float,
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self.primitives.bool,
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].iter().any(|allowed_ty| self.unifier.unioned(ret_ty, *allowed_ty))
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}
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TypeEnum::TTuple { ty } => ty.iter().all(|t| self.check_return_value_ty(*t)),
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_ => false,
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}
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}
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// check statements for proper identifier def-use and return on all paths
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fn check_stmt(
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&mut self,
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stmt: &Stmt<Option<Type>>,
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defined_identifiers: &mut HashSet<StrRef>,
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) -> Result<bool, HashSet<String>> {
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match &stmt.node {
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StmtKind::For { target, iter, body, orelse, .. } => {
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self.check_expr(iter, defined_identifiers)?;
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self.should_have_value(iter)?;
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let mut local_defined_identifiers = defined_identifiers.clone();
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for stmt in orelse {
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self.check_stmt(stmt, &mut local_defined_identifiers)?;
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}
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let mut local_defined_identifiers = defined_identifiers.clone();
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self.check_pattern(target, &mut local_defined_identifiers)?;
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self.should_have_value(target)?;
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for stmt in body {
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self.check_stmt(stmt, &mut local_defined_identifiers)?;
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}
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Ok(false)
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}
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StmtKind::If { test, body, orelse, .. } => {
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self.check_expr(test, defined_identifiers)?;
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self.should_have_value(test)?;
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let mut body_identifiers = defined_identifiers.clone();
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let mut orelse_identifiers = defined_identifiers.clone();
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let body_returned = self.check_block(body, &mut body_identifiers)?;
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let orelse_returned = self.check_block(orelse, &mut orelse_identifiers)?;
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for ident in &body_identifiers {
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if !defined_identifiers.contains(ident) && orelse_identifiers.contains(ident) {
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defined_identifiers.insert(*ident);
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}
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}
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Ok(body_returned && orelse_returned)
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}
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StmtKind::While { test, body, orelse, .. } => {
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self.check_expr(test, defined_identifiers)?;
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self.should_have_value(test)?;
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let mut defined_identifiers = defined_identifiers.clone();
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self.check_block(body, &mut defined_identifiers)?;
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self.check_block(orelse, &mut defined_identifiers)?;
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Ok(false)
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}
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StmtKind::With { items, body, .. } => {
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let mut new_defined_identifiers = defined_identifiers.clone();
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for item in items {
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self.check_expr(&item.context_expr, defined_identifiers)?;
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if let Some(var) = item.optional_vars.as_ref() {
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self.check_pattern(var, &mut new_defined_identifiers)?;
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}
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}
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self.check_block(body, &mut new_defined_identifiers)?;
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Ok(false)
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}
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StmtKind::Try { body, handlers, orelse, finalbody, .. } => {
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self.check_block(body, &mut defined_identifiers.clone())?;
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self.check_block(orelse, &mut defined_identifiers.clone())?;
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for handler in handlers {
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let mut defined_identifiers = defined_identifiers.clone();
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let ast::ExcepthandlerKind::ExceptHandler { name, body, .. } = &handler.node;
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if let Some(name) = name {
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defined_identifiers.insert(*name);
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}
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self.check_block(body, &mut defined_identifiers)?;
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}
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self.check_block(finalbody, defined_identifiers)?;
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Ok(false)
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}
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StmtKind::Expr { value, .. } => {
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self.check_expr(value, defined_identifiers)?;
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Ok(false)
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}
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StmtKind::Assign { targets, value, .. } => {
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self.check_expr(value, defined_identifiers)?;
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self.should_have_value(value)?;
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for target in targets {
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self.check_pattern(target, defined_identifiers)?;
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}
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Ok(false)
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}
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StmtKind::AnnAssign { target, value, .. } => {
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if let Some(value) = value {
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self.check_expr(value, defined_identifiers)?;
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self.should_have_value(value)?;
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self.check_pattern(target, defined_identifiers)?;
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}
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Ok(false)
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}
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StmtKind::Return { value, .. } => {
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if let Some(value) = value {
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self.check_expr(value, defined_identifiers)?;
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self.should_have_value(value)?;
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// Check that the return value is a non-`alloca` type, effectively only allowing primitive types.
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// This is a workaround preventing the caller from using a variable `alloca`-ed in the body, which
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// is freed when the function returns.
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if let Some(ret_ty) = value.custom {
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// Explicitly allow ellipsis as a return value, as the type of the ellipsis is contextually
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// inferred and just generates an unconditional assertion
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if matches!(value.node, ExprKind::Constant { value: Constant::Ellipsis, .. }) {
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return Ok(true)
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}
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if !self.check_return_value_ty(ret_ty) {
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return Err(HashSet::from([
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format!(
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"return value of type {} must be a primitive or a tuple of primitives at {}",
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self.unifier.stringify(ret_ty),
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value.location,
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),
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]))
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}
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}
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}
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Ok(true)
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}
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StmtKind::Raise { exc, .. } => {
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if let Some(value) = exc {
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self.check_expr(value, defined_identifiers)?;
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}
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Ok(true)
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}
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// break, raise, etc.
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_ => Ok(false),
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}
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}
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pub fn check_block(
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&mut self,
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block: &[Stmt<Option<Type>>],
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defined_identifiers: &mut HashSet<StrRef>,
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) -> Result<bool, HashSet<String>> {
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let mut ret = false;
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for stmt in block {
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if ret {
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eprintln!("warning: dead code at {}\n", stmt.location);
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}
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if self.check_stmt(stmt, defined_identifiers)? {
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ret = true;
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}
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}
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Ok(ret)
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}
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}
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