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typeck/expr.rs: extract out check_expr_repeat.

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This commit is contained in:
Mazdak Farrokhzad 2019-06-15 02:36:07 +02:00
parent 877d834c65
commit 82cac1505c
1 changed files with 73 additions and 62 deletions
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135
src/librustc_typeck/check/expr.rs
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@ -128,68 +128,7 @@ pub(super) fn check_expr_kind(
self.check_expr_array(args, expected, expr)
}
ExprKind::Repeat(ref element, ref count) => {
let count_def_id = tcx.hir().local_def_id_from_hir_id(count.hir_id);
let count = if self.const_param_def_id(count).is_some() {
Ok(self.to_const(count, self.tcx.type_of(count_def_id)))
} else {
let param_env = ty::ParamEnv::empty();
let substs = InternalSubsts::identity_for_item(tcx.global_tcx(), count_def_id);
let instance = ty::Instance::resolve(
tcx.global_tcx(),
param_env,
count_def_id,
substs,
).unwrap();
let global_id = GlobalId {
instance,
promoted: None
};
tcx.const_eval(param_env.and(global_id))
};
let uty = match expected {
ExpectHasType(uty) => {
match uty.sty {
ty::Array(ty, _) | ty::Slice(ty) => Some(ty),
_ => None
}
}
_ => None
};
let (element_ty, t) = match uty {
Some(uty) => {
self.check_expr_coercable_to_type(&element, uty);
(uty, uty)
}
None => {
let ty = self.next_ty_var(TypeVariableOrigin {
kind: TypeVariableOriginKind::MiscVariable,
span: element.span,
});
let element_ty = self.check_expr_has_type_or_error(&element, ty);
(element_ty, ty)
}
};
if let Ok(count) = count {
let zero_or_one = count.assert_usize(tcx).map_or(false, |count| count <= 1);
if !zero_or_one {
// For [foo, ..n] where n > 1, `foo` must have
// Copy type:
let lang_item = self.tcx.require_lang_item(lang_items::CopyTraitLangItem);
self.require_type_meets(t, expr.span, traits::RepeatVec, lang_item);
}
}
if element_ty.references_error() {
tcx.types.err
} else if let Ok(count) = count {
tcx.mk_ty(ty::Array(t, count))
} else {
tcx.types.err
}
self.check_expr_repeat(element, count, expected, expr)
}
ExprKind::Tup(ref elts) => {
let flds = expected.only_has_type(self).and_then(|ty| {
@ -824,4 +763,76 @@ fn check_expr_array(
};
self.tcx.mk_array(element_ty, args.len() as u64)
}
fn check_expr_repeat(
&self,
element: &'tcx hir::Expr,
count: &'tcx hir::AnonConst,
expected: Expectation<'tcx>,
expr: &'tcx hir::Expr,
) -> Ty<'tcx> {
let tcx = self.tcx;
let count_def_id = tcx.hir().local_def_id_from_hir_id(count.hir_id);
let count = if self.const_param_def_id(count).is_some() {
Ok(self.to_const(count, tcx.type_of(count_def_id)))
} else {
let param_env = ty::ParamEnv::empty();
let substs = InternalSubsts::identity_for_item(tcx.global_tcx(), count_def_id);
let instance = ty::Instance::resolve(
tcx.global_tcx(),
param_env,
count_def_id,
substs,
).unwrap();
let global_id = GlobalId {
instance,
promoted: None
};
tcx.const_eval(param_env.and(global_id))
};
let uty = match expected {
ExpectHasType(uty) => {
match uty.sty {
ty::Array(ty, _) | ty::Slice(ty) => Some(ty),
_ => None
}
}
_ => None
};
let (element_ty, t) = match uty {
Some(uty) => {
self.check_expr_coercable_to_type(&element, uty);
(uty, uty)
}
None => {
let ty = self.next_ty_var(TypeVariableOrigin {
kind: TypeVariableOriginKind::MiscVariable,
span: element.span,
});
let element_ty = self.check_expr_has_type_or_error(&element, ty);
(element_ty, ty)
}
};
if let Ok(count) = count {
let zero_or_one = count.assert_usize(tcx).map_or(false, |count| count <= 1);
if !zero_or_one {
// For [foo, ..n] where n > 1, `foo` must have
// Copy type:
let lang_item = tcx.require_lang_item(lang_items::CopyTraitLangItem);
self.require_type_meets(t, expr.span, traits::RepeatVec, lang_item);
}
}
if element_ty.references_error() {
tcx.types.err
} else if let Ok(count) = count {
tcx.mk_ty(ty::Array(t, count))
} else {
tcx.types.err
}
}
}