From 6b67c46a253d453674401fad70c515d8fd439e35 Mon Sep 17 00:00:00 2001 From: Camille GILLOT Date: Sat, 24 Aug 2024 18:19:38 +0000 Subject: [PATCH 1/2] Compute array length from type for unconditional panic. --- .../rustc_mir_transform/src/known_panics_lint.rs | 16 +++++++++------- tests/ui/lint/unconditional_panic_promoted.rs | 8 ++++++++ .../ui/lint/unconditional_panic_promoted.stderr | 10 ++++++++++ 3 files changed, 27 insertions(+), 7 deletions(-) create mode 100644 tests/ui/lint/unconditional_panic_promoted.rs create mode 100644 tests/ui/lint/unconditional_panic_promoted.stderr diff --git a/compiler/rustc_mir_transform/src/known_panics_lint.rs b/compiler/rustc_mir_transform/src/known_panics_lint.rs index ccc029b1e281e..8f490094d6030 100644 --- a/compiler/rustc_mir_transform/src/known_panics_lint.rs +++ b/compiler/rustc_mir_transform/src/known_panics_lint.rs @@ -600,13 +600,15 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { } Len(place) => { - let len = match self.get_const(place)? { - Value::Immediate(src) => src.len(&self.ecx).discard_err()?, - Value::Aggregate { fields, .. } => fields.len() as u64, - Value::Uninit => match place.ty(self.local_decls(), self.tcx).ty.kind() { - ty::Array(_, n) => n.try_eval_target_usize(self.tcx, self.param_env)?, - _ => return None, - }, + let len = if let ty::Array(_, n) = place.ty(self.local_decls(), self.tcx).ty.kind() + { + n.try_eval_target_usize(self.tcx, self.param_env)? + } else { + match self.get_const(place)? { + Value::Immediate(src) => src.len(&self.ecx).discard_err()?, + Value::Aggregate { fields, .. } => fields.len() as u64, + Value::Uninit => return None, + } }; ImmTy::from_scalar(Scalar::from_target_usize(len, self), layout).into() } diff --git a/tests/ui/lint/unconditional_panic_promoted.rs b/tests/ui/lint/unconditional_panic_promoted.rs new file mode 100644 index 0000000000000..37bcf04651352 --- /dev/null +++ b/tests/ui/lint/unconditional_panic_promoted.rs @@ -0,0 +1,8 @@ +//@ build-fail + +fn main() { + // MIR encodes this as a reborrow from a promoted constant. + // But the array lenth can still be gotten from the type. + let slice = &[0, 1]; + let _ = slice[2]; //~ ERROR: this operation will panic at runtime [unconditional_panic] +} diff --git a/tests/ui/lint/unconditional_panic_promoted.stderr b/tests/ui/lint/unconditional_panic_promoted.stderr new file mode 100644 index 0000000000000..647a84a55fda5 --- /dev/null +++ b/tests/ui/lint/unconditional_panic_promoted.stderr @@ -0,0 +1,10 @@ +error: this operation will panic at runtime + --> $DIR/unconditional_panic_promoted.rs:7:13 + | +LL | let _ = slice[2]; + | ^^^^^^^^ index out of bounds: the length is 2 but the index is 2 + | + = note: `#[deny(unconditional_panic)]` on by default + +error: aborting due to 1 previous error + From 479779d6a90cc228fc45b5126c558ca52539b2c2 Mon Sep 17 00:00:00 2001 From: Camille GILLOT Date: Sun, 25 Aug 2024 12:13:15 +0000 Subject: [PATCH 2/2] Bless clippy. --- .../clippy/tests/ui-toml/unwrap_used/unwrap_used.fixed | 1 + src/tools/clippy/tests/ui-toml/unwrap_used/unwrap_used.rs | 1 + .../clippy/tests/ui-toml/unwrap_used/unwrap_used.stderr | 2 +- src/tools/clippy/tests/ui/get_unwrap.fixed | 1 + src/tools/clippy/tests/ui/get_unwrap.rs | 1 + src/tools/clippy/tests/ui/get_unwrap.stderr | 8 ++++---- 6 files changed, 9 insertions(+), 5 deletions(-) diff --git a/src/tools/clippy/tests/ui-toml/unwrap_used/unwrap_used.fixed b/src/tools/clippy/tests/ui-toml/unwrap_used/unwrap_used.fixed index baf939af24efb..cdb8fa0454cd4 100644 --- a/src/tools/clippy/tests/ui-toml/unwrap_used/unwrap_used.fixed +++ b/src/tools/clippy/tests/ui-toml/unwrap_used/unwrap_used.fixed @@ -86,6 +86,7 @@ mod issue9612 { util(); } + #[allow(unconditional_panic)] fn util() { let _a: u8 = 4.try_into().unwrap(); let _a: u8 = 5.try_into().expect(""); diff --git a/src/tools/clippy/tests/ui-toml/unwrap_used/unwrap_used.rs b/src/tools/clippy/tests/ui-toml/unwrap_used/unwrap_used.rs index e300ba18c3309..e53d53db5f7a4 100644 --- a/src/tools/clippy/tests/ui-toml/unwrap_used/unwrap_used.rs +++ b/src/tools/clippy/tests/ui-toml/unwrap_used/unwrap_used.rs @@ -86,6 +86,7 @@ mod issue9612 { util(); } + #[allow(unconditional_panic)] fn util() { let _a: u8 = 4.try_into().unwrap(); let _a: u8 = 5.try_into().expect(""); diff --git a/src/tools/clippy/tests/ui-toml/unwrap_used/unwrap_used.stderr b/src/tools/clippy/tests/ui-toml/unwrap_used/unwrap_used.stderr index 320578bfabce0..b58ce9b8af3e4 100644 --- a/src/tools/clippy/tests/ui-toml/unwrap_used/unwrap_used.stderr +++ b/src/tools/clippy/tests/ui-toml/unwrap_used/unwrap_used.stderr @@ -274,7 +274,7 @@ LL | let _ = &boxed_slice[1]; | ~~~~~~~~~~~~~~~ error: called `.get().unwrap()` on a slice - --> tests/ui-toml/unwrap_used/unwrap_used.rs:93:17 + --> tests/ui-toml/unwrap_used/unwrap_used.rs:94:17 | LL | let _ = Box::new([0]).get(1).unwrap(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/src/tools/clippy/tests/ui/get_unwrap.fixed b/src/tools/clippy/tests/ui/get_unwrap.fixed index 62beb195939c6..2dd3c30a4e29b 100644 --- a/src/tools/clippy/tests/ui/get_unwrap.fixed +++ b/src/tools/clippy/tests/ui/get_unwrap.fixed @@ -70,6 +70,7 @@ fn main() { mod issue9909 { #![allow(clippy::identity_op, clippy::unwrap_used, dead_code)] + #[allow(unconditional_panic)] fn reduced() { let f = &[1, 2, 3]; diff --git a/src/tools/clippy/tests/ui/get_unwrap.rs b/src/tools/clippy/tests/ui/get_unwrap.rs index 1e09ff5c67e51..94226564cacb5 100644 --- a/src/tools/clippy/tests/ui/get_unwrap.rs +++ b/src/tools/clippy/tests/ui/get_unwrap.rs @@ -70,6 +70,7 @@ fn main() { mod issue9909 { #![allow(clippy::identity_op, clippy::unwrap_used, dead_code)] + #[allow(unconditional_panic)] fn reduced() { let f = &[1, 2, 3]; diff --git a/src/tools/clippy/tests/ui/get_unwrap.stderr b/src/tools/clippy/tests/ui/get_unwrap.stderr index 0f8b279da1e7a..8eacb249c60c6 100644 --- a/src/tools/clippy/tests/ui/get_unwrap.stderr +++ b/src/tools/clippy/tests/ui/get_unwrap.stderr @@ -266,7 +266,7 @@ LL | let _ = some_vec.get_mut(0..1).unwrap().to_vec(); = help: consider using `expect()` to provide a better panic message error: called `.get().unwrap()` on a slice - --> tests/ui/get_unwrap.rs:77:24 + --> tests/ui/get_unwrap.rs:78:24 | LL | let _x: &i32 = f.get(1 + 2).unwrap(); | ^^^^^^^^^^^^^^^^^^^^^ @@ -277,7 +277,7 @@ LL | let _x: &i32 = &f[1 + 2]; | ~~~~~~~~~ error: called `.get().unwrap()` on a slice - --> tests/ui/get_unwrap.rs:80:18 + --> tests/ui/get_unwrap.rs:81:18 | LL | let _x = f.get(1 + 2).unwrap().to_string(); | ^^^^^^^^^^^^^^^^^^^^^ @@ -288,7 +288,7 @@ LL | let _x = f[1 + 2].to_string(); | ~~~~~~~~ error: called `.get().unwrap()` on a slice - --> tests/ui/get_unwrap.rs:83:18 + --> tests/ui/get_unwrap.rs:84:18 | LL | let _x = f.get(1 + 2).unwrap().abs(); | ^^^^^^^^^^^^^^^^^^^^^ @@ -299,7 +299,7 @@ LL | let _x = f[1 + 2].abs(); | ~~~~~~~~ error: called `.get_mut().unwrap()` on a slice - --> tests/ui/get_unwrap.rs:100:33 + --> tests/ui/get_unwrap.rs:101:33 | LL | let b = rest.get_mut(linidx(j, k) - linidx(i, k) - 1).unwrap(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^