From a929316aed324598825e5a74a4082d09a846df32 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Esteban=20K=C3=BCber?= <esteban@kuber.com.ar>
Date: Fri, 23 Dec 2022 12:44:47 -0800
Subject: [PATCH] Suggest `.clone()` on method call move errors
---
Cargo.lock | 1 +
compiler/rustc_borrowck/Cargo.toml | 1 +
.../rustc_borrowck/src/diagnostics/mod.rs | 43 +++++++++++++++----
src/test/ui/moves/suggest-clone.fixed | 11 +++++
src/test/ui/moves/suggest-clone.rs | 11 +++++
src/test/ui/moves/suggest-clone.stderr | 22 ++++++++++
6 files changed, 80 insertions(+), 9 deletions(-)
create mode 100644 src/test/ui/moves/suggest-clone.fixed
create mode 100644 src/test/ui/moves/suggest-clone.rs
create mode 100644 src/test/ui/moves/suggest-clone.stderr
diff --git a/Cargo.lock b/Cargo.lock
index 5d05a09f038..6de8ba0f8e6 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3447,6 +3447,7 @@ dependencies = [
"rustc_errors",
"rustc_graphviz",
"rustc_hir",
+ "rustc_hir_analysis",
"rustc_index",
"rustc_infer",
"rustc_lexer",
diff --git a/compiler/rustc_borrowck/Cargo.toml b/compiler/rustc_borrowck/Cargo.toml
index 87c113f3e30..f5001172754 100644
--- a/compiler/rustc_borrowck/Cargo.toml
+++ b/compiler/rustc_borrowck/Cargo.toml
@@ -15,6 +15,7 @@ rustc_data_structures = { path = "../rustc_data_structures" }
rustc_errors = { path = "../rustc_errors" }
rustc_graphviz = { path = "../rustc_graphviz" }
rustc_hir = { path = "../rustc_hir" }
+rustc_hir_analysis = { path = "../rustc_hir_analysis" }
rustc_index = { path = "../rustc_index" }
rustc_infer = { path = "../rustc_infer" }
rustc_lexer = { path = "../rustc_lexer" }
diff --git a/compiler/rustc_borrowck/src/diagnostics/mod.rs b/compiler/rustc_borrowck/src/diagnostics/mod.rs
index 213b8b064f9..5250f39003d 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mod.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mod.rs
@@ -6,6 +6,7 @@ use rustc_errors::{Applicability, Diagnostic};
use rustc_hir as hir;
use rustc_hir::def::{CtorKind, Namespace};
use rustc_hir::GeneratorKind;
+use rustc_hir_analysis::hir_ty_to_ty;
use rustc_infer::infer::TyCtxtInferExt;
use rustc_middle::mir::tcx::PlaceTy;
use rustc_middle::mir::{
@@ -1066,18 +1067,16 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
}
CallKind::Normal { self_arg, desugaring, method_did } => {
let self_arg = self_arg.unwrap();
+ let tcx = self.infcx.tcx;
if let Some((CallDesugaringKind::ForLoopIntoIter, _)) = desugaring {
- let ty = moved_place.ty(self.body, self.infcx.tcx).ty;
- let suggest = match self.infcx.tcx.get_diagnostic_item(sym::IntoIterator) {
+ let ty = moved_place.ty(self.body, tcx).ty;
+ let suggest = match tcx.get_diagnostic_item(sym::IntoIterator) {
Some(def_id) => {
let infcx = self.infcx.tcx.infer_ctxt().build();
type_known_to_meet_bound_modulo_regions(
&infcx,
self.param_env,
- infcx.tcx.mk_imm_ref(
- infcx.tcx.lifetimes.re_erased,
- infcx.tcx.erase_regions(ty),
- ),
+ tcx.mk_imm_ref(tcx.lifetimes.re_erased, tcx.erase_regions(ty)),
def_id,
DUMMY_SP,
)
@@ -1133,8 +1132,8 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
place_name, partially_str, loop_message
),
);
- if let ty::Adt(def, ..)
- = moved_place.ty(self.body, self.infcx.tcx).ty.kind()
+ let ty = moved_place.ty(self.body, self.infcx.tcx).ty;
+ if let ty::Adt(def, ..) = ty.kind()
&& Some(def.did()) == self.infcx.tcx.lang_items().pin_type()
{
err.span_suggestion_verbose(
@@ -1144,8 +1143,34 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
Applicability::MaybeIncorrect,
);
}
+ if let Some(clone_trait) = tcx.lang_items().clone_trait() {
+ // We can't use `predicate_may_hold` or `can_eq` without ICEs in
+ // borrowck because of the inference context, so we do a poor-man's
+ // version here.
+ for impl_def_id in tcx.all_impls(clone_trait) {
+ if let Some(def_id) = impl_def_id.as_local()
+ && let hir_id = tcx.hir().local_def_id_to_hir_id(def_id)
+ && let hir::Node::Item(hir::Item {
+ kind: hir::ItemKind::Impl(hir::Impl {
+ self_ty,
+ ..
+ }),
+ ..
+ }) = tcx.hir().get(hir_id)
+ {
+ if ty == hir_ty_to_ty(tcx, self_ty) {
+ err.span_suggestion_verbose(
+ fn_call_span.shrink_to_lo(),
+ "you can `clone` the value and consume it, but this \
+ might not be your desired behavior",
+ "clone().".to_string(),
+ Applicability::MaybeIncorrect,
+ );
+ }
+ }
+ }
+ }
}
- let tcx = self.infcx.tcx;
// Avoid pointing to the same function in multiple different
// error messages.
if span != DUMMY_SP && self.fn_self_span_reported.insert(self_arg.span) {
diff --git a/src/test/ui/moves/suggest-clone.fixed b/src/test/ui/moves/suggest-clone.fixed
new file mode 100644
index 00000000000..204bfdb10b0
--- /dev/null
+++ b/src/test/ui/moves/suggest-clone.fixed
@@ -0,0 +1,11 @@
+// run-rustfix
+
+#[derive(Clone)]
+struct Foo;
+impl Foo {
+ fn foo(self) {}
+}
+fn main() {
+ let foo = &Foo;
+ foo.clone().foo(); //~ ERROR cannot move out
+}
diff --git a/src/test/ui/moves/suggest-clone.rs b/src/test/ui/moves/suggest-clone.rs
new file mode 100644
index 00000000000..25dd9f006f9
--- /dev/null
+++ b/src/test/ui/moves/suggest-clone.rs
@@ -0,0 +1,11 @@
+// run-rustfix
+
+#[derive(Clone)]
+struct Foo;
+impl Foo {
+ fn foo(self) {}
+}
+fn main() {
+ let foo = &Foo;
+ foo.foo(); //~ ERROR cannot move out
+}
diff --git a/src/test/ui/moves/suggest-clone.stderr b/src/test/ui/moves/suggest-clone.stderr
new file mode 100644
index 00000000000..cbb3dfea3ba
--- /dev/null
+++ b/src/test/ui/moves/suggest-clone.stderr
@@ -0,0 +1,22 @@
+error[E0507]: cannot move out of `*foo` which is behind a shared reference
+ --> $DIR/suggest-clone.rs:10:5
+ |
+LL | foo.foo();
+ | ^^^^-----
+ | | |
+ | | `*foo` moved due to this method call
+ | move occurs because `*foo` has type `Foo`, which does not implement the `Copy` trait
+ |
+note: `Foo::foo` takes ownership of the receiver `self`, which moves `*foo`
+ --> $DIR/suggest-clone.rs:6:12
+ |
+LL | fn foo(self) {}
+ | ^^^^
+help: you can `clone` the value and consume it, but this might not be your desired behavior
+ |
+LL | foo.clone().foo();
+ | ++++++++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0507`.