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Rollup merge of #65743 - eddyb:generator-on-call, r=matthewjasper

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rustc_typeck: don't record direct callees in generator_interior.

For expressions like `f(g().await)` we were recording `f` as needing to be kept in a temporary (and therefore be tracked by the generator type) across the suspend, even if a function/method path.
However, this is never needed, and can cause issues with complex function types (see #65244).

cc @Zoxc @nikomatsakis
This commit is contained in:
Mazdak Farrokhzad 2019-10-26 14:17:40 +02:00 committed by GitHub
commit 4f43352964
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 41 additions and 14 deletions
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31
src/librustc_typeck/check/generator_interior.rs
View File

@ -3,9 +3,10 @@
//! is calculated in `rustc_mir::transform::generator` and may be a subset of the
//! types computed here.
use rustc::hir::def::{CtorKind, DefKind, Res};
use rustc::hir::def_id::DefId;
use rustc::hir::intravisit::{self, Visitor, NestedVisitorMap};
use rustc::hir::{self, Pat, PatKind, Expr};
use rustc::hir::{self, Pat, PatKind, Expr, ExprKind};
use rustc::middle::region::{self, YieldData};
use rustc::ty::{self, Ty};
use syntax_pos::Span;
@ -184,7 +185,33 @@ fn visit_pat(&mut self, pat: &'tcx Pat) {
}
fn visit_expr(&mut self, expr: &'tcx Expr) {
intravisit::walk_expr(self, expr);
match &expr.kind {
ExprKind::Call(callee, args) => match &callee.kind {
ExprKind::Path(qpath) => {
let res = self.fcx.tables.borrow().qpath_res(qpath, callee.hir_id);
match res {
// Direct calls never need to keep the callee `ty::FnDef`
// ZST in a temporary, so skip its type, just in case it
// can significantly complicate the generator type.
Res::Def(DefKind::Fn, _) |
Res::Def(DefKind::Method, _) |
Res::Def(DefKind::Ctor(_, CtorKind::Fn), _) => {
// NOTE(eddyb) this assumes a path expression has
// no nested expressions to keep track of.
self.expr_count += 1;
// Record the rest of the call expression normally.
for arg in args {
self.visit_expr(arg);
}
}
_ => intravisit::walk_expr(self, expr),
}
}
_ => intravisit::walk_expr(self, expr),
}
_ => intravisit::walk_expr(self, expr),
}
self.expr_count += 1;

24
src/test/ui/async-await/async-fn-nonsend.stderr
View File

@ -9,9 +9,9 @@ LL | assert_send(local_dropped_before_await());
|
= help: within `impl std::future::Future`, the trait `std::marker::Send` is not implemented for `std::rc::Rc<()>`
= note: required because it appears within the type `impl std::fmt::Debug`
= note: required because it appears within the type `{impl std::fmt::Debug, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}`
= note: required because it appears within the type `[static generator@$DIR/async-fn-nonsend.rs:21:39: 26:2 {impl std::fmt::Debug, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}]`
= note: required because it appears within the type `std::future::GenFuture<[static generator@$DIR/async-fn-nonsend.rs:21:39: 26:2 {impl std::fmt::Debug, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}]>`
= note: required because it appears within the type `{impl std::fmt::Debug, impl std::future::Future, impl std::future::Future, ()}`
= note: required because it appears within the type `[static generator@$DIR/async-fn-nonsend.rs:21:39: 26:2 {impl std::fmt::Debug, impl std::future::Future, impl std::future::Future, ()}]`
= note: required because it appears within the type `std::future::GenFuture<[static generator@$DIR/async-fn-nonsend.rs:21:39: 26:2 {impl std::fmt::Debug, impl std::future::Future, impl std::future::Future, ()}]>`
= note: required because it appears within the type `impl std::future::Future`
= note: required because it appears within the type `impl std::future::Future`
@ -26,9 +26,9 @@ LL | assert_send(non_send_temporary_in_match());
|
= help: within `impl std::future::Future`, the trait `std::marker::Send` is not implemented for `std::rc::Rc<()>`
= note: required because it appears within the type `impl std::fmt::Debug`
= note: required because it appears within the type `{fn(impl std::fmt::Debug) -> std::option::Option<impl std::fmt::Debug> {std::option::Option::<impl std::fmt::Debug>::Some}, fn() -> impl std::fmt::Debug {non_send}, impl std::fmt::Debug, std::option::Option<impl std::fmt::Debug>, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}`
= note: required because it appears within the type `[static generator@$DIR/async-fn-nonsend.rs:28:40: 37:2 {fn(impl std::fmt::Debug) -> std::option::Option<impl std::fmt::Debug> {std::option::Option::<impl std::fmt::Debug>::Some}, fn() -> impl std::fmt::Debug {non_send}, impl std::fmt::Debug, std::option::Option<impl std::fmt::Debug>, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}]`
= note: required because it appears within the type `std::future::GenFuture<[static generator@$DIR/async-fn-nonsend.rs:28:40: 37:2 {fn(impl std::fmt::Debug) -> std::option::Option<impl std::fmt::Debug> {std::option::Option::<impl std::fmt::Debug>::Some}, fn() -> impl std::fmt::Debug {non_send}, impl std::fmt::Debug, std::option::Option<impl std::fmt::Debug>, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}]>`
= note: required because it appears within the type `{impl std::fmt::Debug, std::option::Option<impl std::fmt::Debug>, impl std::future::Future, impl std::future::Future, ()}`
= note: required because it appears within the type `[static generator@$DIR/async-fn-nonsend.rs:28:40: 37:2 {impl std::fmt::Debug, std::option::Option<impl std::fmt::Debug>, impl std::future::Future, impl std::future::Future, ()}]`
= note: required because it appears within the type `std::future::GenFuture<[static generator@$DIR/async-fn-nonsend.rs:28:40: 37:2 {impl std::fmt::Debug, std::option::Option<impl std::fmt::Debug>, impl std::future::Future, impl std::future::Future, ()}]>`
= note: required because it appears within the type `impl std::future::Future`
= note: required because it appears within the type `impl std::future::Future`
@ -45,9 +45,9 @@ LL | assert_send(non_sync_with_method_call());
= note: required because of the requirements on the impl of `std::marker::Send` for `&mut dyn std::fmt::Write`
= note: required because it appears within the type `std::fmt::Formatter<'_>`
= note: required because of the requirements on the impl of `std::marker::Send` for `&mut std::fmt::Formatter<'_>`
= note: required because it appears within the type `for<'r, 's> {&'r mut std::fmt::Formatter<'s>, bool, bool, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}`
= note: required because it appears within the type `[static generator@$DIR/async-fn-nonsend.rs:39:38: 45:2 for<'r, 's> {&'r mut std::fmt::Formatter<'s>, bool, bool, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}]`
= note: required because it appears within the type `std::future::GenFuture<[static generator@$DIR/async-fn-nonsend.rs:39:38: 45:2 for<'r, 's> {&'r mut std::fmt::Formatter<'s>, bool, bool, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}]>`
= note: required because it appears within the type `for<'r, 's> {&'r mut std::fmt::Formatter<'s>, bool, bool, impl std::future::Future, impl std::future::Future, ()}`
= note: required because it appears within the type `[static generator@$DIR/async-fn-nonsend.rs:39:38: 45:2 for<'r, 's> {&'r mut std::fmt::Formatter<'s>, bool, bool, impl std::future::Future, impl std::future::Future, ()}]`
= note: required because it appears within the type `std::future::GenFuture<[static generator@$DIR/async-fn-nonsend.rs:39:38: 45:2 for<'r, 's> {&'r mut std::fmt::Formatter<'s>, bool, bool, impl std::future::Future, impl std::future::Future, ()}]>`
= note: required because it appears within the type `impl std::future::Future`
= note: required because it appears within the type `impl std::future::Future`
@ -68,9 +68,9 @@ LL | assert_send(non_sync_with_method_call());
= note: required because of the requirements on the impl of `std::marker::Send` for `std::slice::Iter<'_, std::fmt::ArgumentV1<'_>>`
= note: required because it appears within the type `std::fmt::Formatter<'_>`
= note: required because of the requirements on the impl of `std::marker::Send` for `&mut std::fmt::Formatter<'_>`
= note: required because it appears within the type `for<'r, 's> {&'r mut std::fmt::Formatter<'s>, bool, bool, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}`
= note: required because it appears within the type `[static generator@$DIR/async-fn-nonsend.rs:39:38: 45:2 for<'r, 's> {&'r mut std::fmt::Formatter<'s>, bool, bool, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}]`
= note: required because it appears within the type `std::future::GenFuture<[static generator@$DIR/async-fn-nonsend.rs:39:38: 45:2 for<'r, 's> {&'r mut std::fmt::Formatter<'s>, bool, bool, fn() -> impl std::future::Future {fut}, impl std::future::Future, impl std::future::Future, ()}]>`
= note: required because it appears within the type `for<'r, 's> {&'r mut std::fmt::Formatter<'s>, bool, bool, impl std::future::Future, impl std::future::Future, ()}`
= note: required because it appears within the type `[static generator@$DIR/async-fn-nonsend.rs:39:38: 45:2 for<'r, 's> {&'r mut std::fmt::Formatter<'s>, bool, bool, impl std::future::Future, impl std::future::Future, ()}]`
= note: required because it appears within the type `std::future::GenFuture<[static generator@$DIR/async-fn-nonsend.rs:39:38: 45:2 for<'r, 's> {&'r mut std::fmt::Formatter<'s>, bool, bool, impl std::future::Future, impl std::future::Future, ()}]>`
= note: required because it appears within the type `impl std::future::Future`
= note: required because it appears within the type `impl std::future::Future`