From f6e5ac640be7ca71f389b6842cfeb83c24bd15c7 Mon Sep 17 00:00:00 2001
From: Eduard-Mihai Burtescu <edy.burt@gmail.com>
Date: Mon, 1 Jul 2019 20:06:30 +0300
Subject: [PATCH] rustc_mir: treat DropAndReplace as Drop + Assign in
qualify_consts.
---
src/librustc_mir/transform/qualify_consts.rs | 23 +++++++++++++---
src/test/ui/consts/const-eval/const_let.rs | 15 +++++++++--
.../ui/consts/const-eval/const_let.stderr | 27 +++++++++++++------
3 files changed, 52 insertions(+), 13 deletions(-)
diff --git a/src/librustc_mir/transform/qualify_consts.rs b/src/librustc_mir/transform/qualify_consts.rs
index f082b5e5a046c..72180d60bd6d0 100644
--- a/src/librustc_mir/transform/qualify_consts.rs
+++ b/src/librustc_mir/transform/qualify_consts.rs
@@ -142,6 +142,7 @@ impl<'a, 'tcx> ConstCx<'a, 'tcx> {
#[derive(Copy, Clone, Debug)]
enum ValueSource<'a, 'tcx> {
Rvalue(&'a Rvalue<'tcx>),
+ DropAndReplace(&'a Operand<'tcx>),
Call {
callee: &'a Operand<'tcx>,
args: &'a [Operand<'tcx>],
@@ -298,6 +299,7 @@ trait Qualif {
fn in_value(cx: &ConstCx<'_, 'tcx>, source: ValueSource<'_, 'tcx>) -> bool {
match source {
ValueSource::Rvalue(rvalue) => Self::in_rvalue(cx, rvalue),
+ ValueSource::DropAndReplace(source) => Self::in_operand(cx, source),
ValueSource::Call { callee, args, return_ty } => {
Self::in_call(cx, callee, args, return_ty)
}
@@ -889,6 +891,7 @@ impl<'a, 'tcx> Checker<'a, 'tcx> {
let target = match body[bb].terminator().kind {
TerminatorKind::Goto { target } |
TerminatorKind::Drop { target, .. } |
+ TerminatorKind::DropAndReplace { target, .. } |
TerminatorKind::Assert { target, .. } |
TerminatorKind::Call { destination: Some((_, target)), .. } => {
Some(target)
@@ -900,7 +903,6 @@ impl<'a, 'tcx> Checker<'a, 'tcx> {
}
TerminatorKind::SwitchInt {..} |
- TerminatorKind::DropAndReplace { .. } |
TerminatorKind::Resume |
TerminatorKind::Abort |
TerminatorKind::GeneratorDrop |
@@ -1393,8 +1395,15 @@ impl<'a, 'tcx> Visitor<'tcx> for Checker<'a, 'tcx> {
for arg in args {
self.visit_operand(arg, location);
}
- } else if let TerminatorKind::Drop { location: ref place, .. } = *kind {
- self.super_terminator_kind(kind, location);
+ } else if let TerminatorKind::Drop {
+ location: ref place, ..
+ } | TerminatorKind::DropAndReplace {
+ location: ref place, ..
+ } = *kind {
+ match *kind {
+ TerminatorKind::DropAndReplace { .. } => {}
+ _ => self.super_terminator_kind(kind, location),
+ }
// Deny *any* live drops anywhere other than functions.
if self.mode.requires_const_checking() {
@@ -1423,6 +1432,14 @@ impl<'a, 'tcx> Visitor<'tcx> for Checker<'a, 'tcx> {
}
}
}
+
+ match *kind {
+ TerminatorKind::DropAndReplace { ref value, .. } => {
+ self.assign(place, ValueSource::DropAndReplace(value), location);
+ self.visit_operand(value, location);
+ }
+ _ => {}
+ }
} else {
// Qualify any operands inside other terminators.
self.super_terminator_kind(kind, location);
diff --git a/src/test/ui/consts/const-eval/const_let.rs b/src/test/ui/consts/const-eval/const_let.rs
index 63321b9120076..18692dbced679 100644
--- a/src/test/ui/consts/const-eval/const_let.rs
+++ b/src/test/ui/consts/const-eval/const_let.rs
@@ -9,10 +9,21 @@ impl Drop for FakeNeedsDrop {
// ok
const X: FakeNeedsDrop = { let x = FakeNeedsDrop; x };
+// ok (used to incorrectly error, see #62273)
+const X2: FakeNeedsDrop = { let x; x = FakeNeedsDrop; x };
+
// error
const Y: FakeNeedsDrop = { let mut x = FakeNeedsDrop; x = FakeNeedsDrop; x };
-//~^ ERROR constant contains unimplemented expression type
+//~^ ERROR destructors cannot be evaluated at compile-time
+
+// error
+const Y2: FakeNeedsDrop = { let mut x; x = FakeNeedsDrop; x = FakeNeedsDrop; x };
+//~^ ERROR destructors cannot be evaluated at compile-time
// error
const Z: () = { let mut x = None; x = Some(FakeNeedsDrop); };
-//~^ ERROR constant contains unimplemented expression type
+//~^ ERROR destructors cannot be evaluated at compile-time
+
+// error
+const Z2: () = { let mut x; x = None; x = Some(FakeNeedsDrop); };
+//~^ ERROR destructors cannot be evaluated at compile-time
diff --git a/src/test/ui/consts/const-eval/const_let.stderr b/src/test/ui/consts/const-eval/const_let.stderr
index 00de97e6fb3a0..0a6a222ae2963 100644
--- a/src/test/ui/consts/const-eval/const_let.stderr
+++ b/src/test/ui/consts/const-eval/const_let.stderr
@@ -1,15 +1,26 @@
-error[E0019]: constant contains unimplemented expression type
- --> $DIR/const_let.rs:13:55
+error[E0493]: destructors cannot be evaluated at compile-time
+ --> $DIR/const_let.rs:16:32
|
LL | const Y: FakeNeedsDrop = { let mut x = FakeNeedsDrop; x = FakeNeedsDrop; x };
- | ^
+ | ^^^^^ constants cannot evaluate destructors
-error[E0019]: constant contains unimplemented expression type
- --> $DIR/const_let.rs:17:35
+error[E0493]: destructors cannot be evaluated at compile-time
+ --> $DIR/const_let.rs:20:33
+ |
+LL | const Y2: FakeNeedsDrop = { let mut x; x = FakeNeedsDrop; x = FakeNeedsDrop; x };
+ | ^^^^^ constants cannot evaluate destructors
+
+error[E0493]: destructors cannot be evaluated at compile-time
+ --> $DIR/const_let.rs:24:21
|
LL | const Z: () = { let mut x = None; x = Some(FakeNeedsDrop); };
- | ^
+ | ^^^^^ constants cannot evaluate destructors
+
+error[E0493]: destructors cannot be evaluated at compile-time
+ --> $DIR/const_let.rs:28:22
+ |
+LL | const Z2: () = { let mut x; x = None; x = Some(FakeNeedsDrop); };
+ | ^^^^^ constants cannot evaluate destructors
-error: aborting due to 2 previous errors
+error: aborting due to 4 previous errors
-For more information about this error, try `rustc --explain E0019`.