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Add support for lengths in array repeats, if they are literals

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Now we will get the type of `[0u8; 4]`.
This commit is contained in:
Jade 2021-05-12 05:59:35 -07:00
parent 73023c0299
commit e666589e63
4 changed files with 22 additions and 11 deletions
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22
crates/hir_ty/src/infer/expr.rs
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@ -1,10 +1,14 @@
//! Type inference for expressions.
use std::iter::{repeat, repeat_with};
use std::{
convert::TryInto,
iter::{repeat, repeat_with},
};
use std::{mem, sync::Arc};
use chalk_ir::{cast::Cast, fold::Shift, ConstData, Mutability, TyVariableKind};
use hir_def::{
builtin_type::BuiltinUint,
expr::{Array, BinaryOp, Expr, ExprId, Literal, Statement, UnaryOp},
path::{GenericArg, GenericArgs},
resolver::resolver_for_expr,
@ -724,7 +728,7 @@ impl<'a> InferenceContext<'a> {
for expr in items.iter() {
self.infer_expr_coerce(*expr, &Expectation::has_type(elem_ty.clone()));
}
Some(items.len())
Some(items.len() as u64)
}
Array::Repeat { initializer, repeat } => {
self.infer_expr_coerce(
@ -737,9 +741,15 @@ impl<'a> InferenceContext<'a> {
TyKind::Scalar(Scalar::Uint(UintTy::Usize)).intern(&Interner),
),
);
// FIXME: we don't know the length here because hir Exprs don't actually
// get the value out of the AST, even though it is there.
None
let repeat_expr = &self.body.exprs[*repeat];
match repeat_expr {
Expr::Literal(Literal::Uint(v, None))
| Expr::Literal(Literal::Uint(v, Some(BuiltinUint::Usize))) => {
(*v).try_into().ok()
}
_ => None,
}
}
};
@ -747,7 +757,7 @@ impl<'a> InferenceContext<'a> {
ty: TyKind::Scalar(Scalar::Uint(UintTy::Usize)).intern(&Interner),
value: ConstValue::Concrete(chalk_ir::ConcreteConst {
interned: len
.map(|len| ConstScalar::Usize(len as u64))
.map(|len| ConstScalar::Usize(len))
.unwrap_or(ConstScalar::Unknown),
}),
};