New lint: unsound_collection_transmute

CHANGELOG.md

@@ -1224,6 +1224,7 @@ Released 2018-09-13
 [`unsafe_removed_from_name`]: https://rust-lang.github.io/rust-clippy/master/index.html#unsafe_removed_from_name
 [`unsafe_vector_initialization`]: https://rust-lang.github.io/rust-clippy/master/index.html#unsafe_vector_initialization
 [`unseparated_literal_suffix`]: https://rust-lang.github.io/rust-clippy/master/index.html#unseparated_literal_suffix
+[`unsound_collection_transmute`]: https://rust-lang.github.io/rust-clippy/master/index.html#unsound_collection_transmute
 [`unstable_as_mut_slice`]: https://rust-lang.github.io/rust-clippy/master/index.html#unstable_as_mut_slice
 [`unstable_as_slice`]: https://rust-lang.github.io/rust-clippy/master/index.html#unstable_as_slice
 [`unused_collect`]: https://rust-lang.github.io/rust-clippy/master/index.html#unused_collect

README.md

@@ -6,7 +6,7 @@
 
 A collection of lints to catch common mistakes and improve your [Rust](https://github.com/rust-lang/rust) code.
 
-[There are 317 lints included in this crate!](https://rust-lang.github.io/rust-clippy/master/index.html)
+[There are 318 lints included in this crate!](https://rust-lang.github.io/rust-clippy/master/index.html)
 
 We have a bunch of lint categories to allow you to choose how much Clippy is supposed to ~~annoy~~ help you:
 

clippy_lints/src/lib.rs

@@ -889,6 +889,7 @@ pub fn register_plugins(reg: &mut rustc_driver::plugin::Registry<'_>, conf: &Con
  transmute::TRANSMUTE_INT_TO_FLOAT,
  transmute::TRANSMUTE_PTR_TO_PTR,
  transmute::TRANSMUTE_PTR_TO_REF,
+ transmute::UNSOUND_COLLECTION_TRANSMUTE,
  transmute::USELESS_TRANSMUTE,
  transmute::WRONG_TRANSMUTE,
  transmuting_null::TRANSMUTING_NULL,
@@ -1143,6 +1144,7 @@ pub fn register_plugins(reg: &mut rustc_driver::plugin::Registry<'_>, conf: &Con
  suspicious_trait_impl::SUSPICIOUS_ARITHMETIC_IMPL,
  suspicious_trait_impl::SUSPICIOUS_OP_ASSIGN_IMPL,
  swap::ALMOST_SWAPPED,
+ transmute::UNSOUND_COLLECTION_TRANSMUTE,
  transmute::WRONG_TRANSMUTE,
  transmuting_null::TRANSMUTING_NULL,
  types::ABSURD_EXTREME_COMPARISONS,

src/lintlist/mod.rs

@@ -6,7 +6,7 @@ pub use lint::Lint;
 pub use lint::LINT_LEVELS;
 
 // begin lint list, do not remove this comment, it’s used in `update_lints`
-pub const ALL_LINTS: [Lint; 317] = [
+pub const ALL_LINTS: [Lint; 318] = [
  Lint {
  name: "absurd_extreme_comparisons",
  group: "correctness",
@@ -2023,6 +2023,13 @@ pub const ALL_LINTS: [Lint; 317] = [
  deprecation: None,
  module: "misc_early",
  },
+ Lint {
+ name: "unsound_collection_transmute",
+ group: "correctness",
+ desc: "transmute between collections of layout-incompatible types",
+ deprecation: None,
+ module: "transmute",
+ },
  Lint {
  name: "unused_io_amount",
  group: "correctness",

tests/ui/transmute.stderr

@@ -116,6 +116,38 @@ error: transmute from a type (`std::vec::Vec<i32>`) to itself
 LL | let _: Vec<i32> = my_transmute(my_vec());
  | ^^^^^^^^^^^^^^^^^^^^^^
 
+error: transmute from `std::vec::Vec<i32>` to `std::vec::Vec<u32>` with mismatched layout is unsound
+ --> $DIR/transmute.rs:83:27
+ |
+LL | let _: Vec<u32> = core::intrinsics::transmute(my_vec());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: `#[deny(clippy::unsound_collection_transmute)]` on by default
+
+error: transmute from `std::vec::Vec<i32>` to `std::vec::Vec<u32>` with mismatched layout is unsound
+ --> $DIR/transmute.rs:84:27
+ |
+LL | let _: Vec<u32> = core::mem::transmute(my_vec());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: transmute from `std::vec::Vec<i32>` to `std::vec::Vec<u32>` with mismatched layout is unsound
+ --> $DIR/transmute.rs:85:27
+ |
+LL | let _: Vec<u32> = std::intrinsics::transmute(my_vec());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: transmute from `std::vec::Vec<i32>` to `std::vec::Vec<u32>` with mismatched layout is unsound
+ --> $DIR/transmute.rs:86:27
+ |
+LL | let _: Vec<u32> = std::mem::transmute(my_vec());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: transmute from `std::vec::Vec<i32>` to `std::vec::Vec<u32>` with mismatched layout is unsound
+ --> $DIR/transmute.rs:87:27
+ |
+LL | let _: Vec<u32> = my_transmute(my_vec());
+ | ^^^^^^^^^^^^^^^^^^^^^^
+
 error: transmute from an integer to a pointer
  --> $DIR/transmute.rs:89:31
  |
@@ -242,5 +274,5 @@ error: transmute from a reference to a reference
 LL | let _: &GenericParam<f32> = std::mem::transmute(&GenericParam { t: 1u32 });
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&*(&GenericParam { t: 1u32 } as *const GenericParam<u32> as *const GenericParam<f32>)`
 
-error: aborting due to 38 previous errors
+error: aborting due to 43 previous errors
 

tests/ui/transmute_collection.rs

@@ -0,0 +1,47 @@
+#![warn(clippy::unsound_collection_transmute)]
+
+use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, VecDeque};
+use std::mem::transmute;
+
+fn main() {
+ unsafe {
+ // wrong size
+ let _ = transmute::<_, Vec<u32>>(vec![0u8]);
+ // wrong layout
+ let _ = transmute::<_, Vec<[u8; 4]>>(vec![1234u32]);
+
+ // wrong size
+ let _ = transmute::<_, VecDeque<u32>>(VecDeque::<u8>::new());
+ // wrong layout
+ let _ = transmute::<_, VecDeque<u32>>(VecDeque::<[u8; 4]>::new());
+
+ // wrong size
+ let _ = transmute::<_, BinaryHeap<u32>>(BinaryHeap::<u8>::new());
+ // wrong layout
+ let _ = transmute::<_, BinaryHeap<u32>>(BinaryHeap::<[u8; 4]>::new());
+
+ // wrong size
+ let _ = transmute::<_, BTreeSet<u32>>(BTreeSet::<u8>::new());
+ // wrong layout
+ let _ = transmute::<_, BTreeSet<u32>>(BTreeSet::<[u8; 4]>::new());
+
+ // wrong size
+ let _ = transmute::<_, HashSet<u32>>(HashSet::<u8>::new());
+ // wrong layout
+ let _ = transmute::<_, HashSet<u32>>(HashSet::<[u8; 4]>::new());
+
+ // wrong size
+ let _ = transmute::<_, BTreeMap<u8, u32>>(BTreeMap::<u8, u8>::new());
+ let _ = transmute::<_, BTreeMap<u8, u32>>(BTreeMap::<u32, u32>::new());
+ // wrong layout
+ let _ = transmute::<_, BTreeMap<u8, u32>>(BTreeMap::<u8, [u8; 4]>::new());
+ let _ = transmute::<_, BTreeMap<u32, u32>>(BTreeMap::<[u8; 4], u32>::new());
+
+ // wrong size
+ let _ = transmute::<_, HashMap<u8, u32>>(HashMap::<u8, u8>::new());
+ let _ = transmute::<_, HashMap<u8, u32>>(HashMap::<u32, u32>::new());
+ // wrong layout
+ let _ = transmute::<_, HashMap<u8, u32>>(HashMap::<u8, [u8; 4]>::new());
+ let _ = transmute::<_, HashMap<u32, u32>>(HashMap::<[u8; 4], u32>::new());
+ }
+}

tests/ui/transmute_collection.stderr

@@ -0,0 +1,112 @@
+error: transmute from `std::vec::Vec<u8>` to `std::vec::Vec<u32>` with mismatched layout is unsound
+ --> $DIR/transmute_collection.rs:9:17
+ |
+LL | let _ = transmute::<_, Vec<u32>>(vec![0u8]);
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: `-D clippy::unsound-collection-transmute` implied by `-D warnings`
+
+error: transmute from `std::vec::Vec<u32>` to `std::vec::Vec<[u8; 4]>` with mismatched layout is unsound
+ --> $DIR/transmute_collection.rs:11:17
+ |
+LL | let _ = transmute::<_, Vec<[u8; 4]>>(vec![1234u32]);
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: transmute from `std::collections::VecDeque<u8>` to `std::collections::VecDeque<u32>` with mismatched layout is unsound
+ --> $DIR/transmute_collection.rs:14:17
+ |
+LL | let _ = transmute::<_, VecDeque<u32>>(VecDeque::<u8>::new());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: transmute from `std::collections::VecDeque<[u8; 4]>` to `std::collections::VecDeque<u32>` with mismatched layout is unsound
+ --> $DIR/transmute_collection.rs:16:17
+ |
+LL | let _ = transmute::<_, VecDeque<u32>>(VecDeque::<[u8; 4]>::new());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: transmute from `std::collections::BinaryHeap<u8>` to `std::collections::BinaryHeap<u32>` with mismatched layout is unsound
+ --> $DIR/transmute_collection.rs:19:17
+ |
+LL | let _ = transmute::<_, BinaryHeap<u32>>(BinaryHeap::<u8>::new());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: transmute from `std::collections::BinaryHeap<[u8; 4]>` to `std::collections::BinaryHeap<u32>` with mismatched layout is unsound
+ --> $DIR/transmute_collection.rs:21:17
+ |
+LL | let _ = transmute::<_, BinaryHeap<u32>>(BinaryHeap::<[u8; 4]>::new());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: transmute from `std::collections::BTreeSet<u8>` to `std::collections::BTreeSet<u32>` with mismatched layout is unsound
+ --> $DIR/transmute_collection.rs:24:17
+ |
+LL | let _ = transmute::<_, BTreeSet<u32>>(BTreeSet::<u8>::new());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: transmute from `std::collections::BTreeSet<[u8; 4]>` to `std::collections::BTreeSet<u32>` with mismatched layout is unsound
+ --> $DIR/transmute_collection.rs:26:17
+ |
+LL | let _ = transmute::<_, BTreeSet<u32>>(BTreeSet::<[u8; 4]>::new());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: transmute from `std::collections::HashSet<u8>` to `std::collections::HashSet<u32>` with mismatched layout is unsound
+ --> $DIR/transmute_collection.rs:29:17
+ |
+LL | let _ = transmute::<_, HashSet<u32>>(HashSet::<u8>::new());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: transmute from `std::collections::HashSet<[u8; 4]>` to `std::collections::HashSet<u32>` with mismatched layout is unsound
+ --> $DIR/transmute_collection.rs:31:17
+ |
+LL | let _ = transmute::<_, HashSet<u32>>(HashSet::<[u8; 4]>::new());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: transmute from `std::collections::BTreeMap<u8, u8>` to `std::collections::BTreeMap<u8, u32>` with mismatched layout is unsound
+ --> $DIR/transmute_collection.rs:34:17
+ |
+LL | let _ = transmute::<_, BTreeMap<u8, u32>>(BTreeMap::<u8, u8>::new());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: transmute from `std::collections::BTreeMap<u32, u32>` to `std::collections::BTreeMap<u8, u32>` with mismatched layout is unsound
+ --> $DIR/transmute_collection.rs:35:17
+ |
+LL | let _ = transmute::<_, BTreeMap<u8, u32>>(BTreeMap::<u32, u32>::new());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: transmute from `std::collections::BTreeMap<u8, [u8; 4]>` to `std::collections::BTreeMap<u8, u32>` with mismatched layout is unsound
+ --> $DIR/transmute_collection.rs:37:17
+ |
+LL | let _ = transmute::<_, BTreeMap<u8, u32>>(BTreeMap::<u8, [u8; 4]>::new());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: transmute from `std::collections::BTreeMap<[u8; 4], u32>` to `std::collections::BTreeMap<u32, u32>` with mismatched layout is unsound
+ --> $DIR/transmute_collection.rs:38:17
+ |
+LL | let _ = transmute::<_, BTreeMap<u32, u32>>(BTreeMap::<[u8; 4], u32>::new());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: transmute from `std::collections::HashMap<u8, u8>` to `std::collections::HashMap<u8, u32>` with mismatched layout is unsound
+ --> $DIR/transmute_collection.rs:41:17
+ |
+LL | let _ = transmute::<_, HashMap<u8, u32>>(HashMap::<u8, u8>::new());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: transmute from `std::collections::HashMap<u32, u32>` to `std::collections::HashMap<u8, u32>` with mismatched layout is unsound
+ --> $DIR/transmute_collection.rs:42:17
+ |
+LL | let _ = transmute::<_, HashMap<u8, u32>>(HashMap::<u32, u32>::new());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: transmute from `std::collections::HashMap<u8, [u8; 4]>` to `std::collections::HashMap<u8, u32>` with mismatched layout is unsound
+ --> $DIR/transmute_collection.rs:44:17
+ |
+LL | let _ = transmute::<_, HashMap<u8, u32>>(HashMap::<u8, [u8; 4]>::new());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: transmute from `std::collections::HashMap<[u8; 4], u32>` to `std::collections::HashMap<u32, u32>` with mismatched layout is unsound
+ --> $DIR/transmute_collection.rs:45:17
+ |
+LL | let _ = transmute::<_, HashMap<u32, u32>>(HashMap::<[u8; 4], u32>::new());
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 18 previous errors
+