rust/crates/hir_ty/src/op.rs
2020-08-13 16:35:29 +02:00

59 lines
2.3 KiB
Rust

//! Helper functions for binary operator type inference.
use hir_def::expr::{ArithOp, BinaryOp, CmpOp};
use super::{InferTy, Ty, TypeCtor};
use crate::ApplicationTy;
pub(super) fn binary_op_return_ty(op: BinaryOp, lhs_ty: Ty, rhs_ty: Ty) -> Ty {
match op {
BinaryOp::LogicOp(_) | BinaryOp::CmpOp(_) => Ty::simple(TypeCtor::Bool),
BinaryOp::Assignment { .. } => Ty::unit(),
BinaryOp::ArithOp(ArithOp::Shl) | BinaryOp::ArithOp(ArithOp::Shr) => match lhs_ty {
Ty::Apply(ApplicationTy { ctor, .. }) => match ctor {
TypeCtor::Int(..) | TypeCtor::Float(..) => lhs_ty,
_ => Ty::Unknown,
},
Ty::Infer(InferTy::IntVar(..)) | Ty::Infer(InferTy::FloatVar(..)) => lhs_ty,
_ => Ty::Unknown,
},
BinaryOp::ArithOp(_) => match rhs_ty {
Ty::Apply(ApplicationTy { ctor, .. }) => match ctor {
TypeCtor::Int(..) | TypeCtor::Float(..) => rhs_ty,
_ => Ty::Unknown,
},
Ty::Infer(InferTy::IntVar(..)) | Ty::Infer(InferTy::FloatVar(..)) => rhs_ty,
_ => Ty::Unknown,
},
}
}
pub(super) fn binary_op_rhs_expectation(op: BinaryOp, lhs_ty: Ty) -> Ty {
match op {
BinaryOp::LogicOp(..) => Ty::simple(TypeCtor::Bool),
BinaryOp::Assignment { op: None } => lhs_ty,
BinaryOp::CmpOp(CmpOp::Eq { .. }) => match lhs_ty {
Ty::Apply(ApplicationTy { ctor, .. }) => match ctor {
TypeCtor::Int(..)
| TypeCtor::Float(..)
| TypeCtor::Str
| TypeCtor::Char
| TypeCtor::Bool => lhs_ty,
_ => Ty::Unknown,
},
Ty::Infer(InferTy::IntVar(..)) | Ty::Infer(InferTy::FloatVar(..)) => lhs_ty,
_ => Ty::Unknown,
},
BinaryOp::ArithOp(ArithOp::Shl) | BinaryOp::ArithOp(ArithOp::Shr) => Ty::Unknown,
BinaryOp::CmpOp(CmpOp::Ord { .. })
| BinaryOp::Assignment { op: Some(_) }
| BinaryOp::ArithOp(_) => match lhs_ty {
Ty::Apply(ApplicationTy { ctor, .. }) => match ctor {
TypeCtor::Int(..) | TypeCtor::Float(..) => lhs_ty,
_ => Ty::Unknown,
},
Ty::Infer(InferTy::IntVar(..)) | Ty::Infer(InferTy::FloatVar(..)) => lhs_ty,
_ => Ty::Unknown,
},
}
}