Use trybuild for testing compilation failures

.github/workflows/ci.yml

@@ -42,9 +42,10 @@ jobs:
           - name: Test macOS 10.15
             os: macos-10.15
             target: x86_64-apple-darwin
-          - name: Test macOS 11
+          - name: Test macOS 11 w. ui tests
             os: macos-11
             target: x86_64-apple-darwin
+            args: --features tests/ui
           - name: Build macOS AArch64
             os: macos-11
             target: aarch64-apple-darwin
@@ -54,11 +55,12 @@ jobs:
             target: x86_64-apple-darwin
             # Oldest macOS version we support
             sdk: 10.7
-          - name: Test macOS nightly
+          - name: Test macOS nightly w. ui tests
             os: macos-latest
             target: x86_64-apple-darwin
             rust:
               toolchain: nightly
+            args: --features tests/ui
           - name: Build macOS 32bit
             os: macos-10.15
             target: i686-apple-darwin

objc2-foundation/src/array.rs

@@ -41,16 +41,6 @@ unsafe impl<T: Sync + Send> Send for NSArray<T, Shared> {}
 unsafe impl<T: Sync> Sync for NSArray<T, Owned> {}
 unsafe impl<T: Send> Send for NSArray<T, Owned> {}
 
-/// ```compile_fail
-/// use objc2::rc::Shared;
-/// use objc2::runtime::Object;
-/// use objc2_foundation::NSArray;
-/// fn needs_send_sync<T: Send + Sync>() {}
-/// needs_send_sync::<NSArray<Object, Shared>>();
-/// ```
-#[cfg(doctest)]
-pub struct NSArrayWithObjectNotSendSync;
-
 object! {
     // TODO: Ensure that this deref to NSArray is safe!
     unsafe pub struct NSMutableArray<T, O: Ownership>: NSArray<T, O> {

objc2-foundation/src/object.rs

@@ -10,19 +10,6 @@ object! {
     unsafe pub struct NSObject: Object;
 }
 
-/// ```compile_fail
-/// use objc2_foundation::NSObject;
-/// fn needs_sync<T: Sync>() {}
-/// needs_sync::<NSObject>();
-/// ```
-/// ```compile_fail
-/// use objc2_foundation::NSObject;
-/// fn needs_send<T: Send>() {}
-/// needs_send::<NSObject>();
-/// ```
-#[cfg(doctest)]
-pub struct NSObjectNotSendNorSync;
-
 impl NSObject {
     unsafe_def_fn!(pub fn new -> Owned);
 

objc2-foundation/src/string.rs

@@ -43,24 +43,6 @@ impl NSString {
     }
 
     /// TODO
-    ///
-    /// ```compile_fail
-    /// # use objc2::rc::autoreleasepool;
-    /// # use objc2_foundation::NSString;
-    /// autoreleasepool(|pool| {
-    ///     let ns_string = NSString::new();
-    ///     let s = ns_string.as_str(pool);
-    ///     drop(ns_string);
-    ///     println!("{}", s);
-    /// });
-    /// ```
-    ///
-    /// ```compile_fail
-    /// # use objc2::rc::autoreleasepool;
-    /// # use objc2_foundation::NSString;
-    /// let ns_string = NSString::new();
-    /// let s = autoreleasepool(|pool| ns_string.as_str(pool));
-    /// ```
     pub fn as_str<'r, 's: 'r, 'p: 'r>(&'s self, pool: &'p AutoreleasePool) -> &'r str {
         // This is necessary until `auto` types stabilizes.
         pool.__verify_is_inner();

objc2-foundation/src/value.rs

@@ -110,14 +110,6 @@ impl<T: 'static + Copy + Encode + fmt::Display> fmt::Display for NSValue<T> {
     }
 }
 
-/// ```compile_fail
-/// use objc2_foundation::NSValue;
-/// fn needs_eq<T: Eq>() {}
-/// needs_eq::<NSValue<f32>>();
-/// ```
-#[cfg(doctest)]
-pub struct NSValueFloatNotEq;
-
 #[cfg(test)]
 mod tests {
     use alloc::format;

objc2/src/rc/autorelease.rs

@@ -25,24 +25,6 @@ pub struct AutoreleasePool {
     p: PhantomData<*mut UnsafeCell<c_void>>,
 }
 
-/// ```
-/// use objc2::rc::AutoreleasePool;
-/// fn needs_nothing<T>() {}
-/// needs_nothing::<AutoreleasePool>();
-/// ```
-/// ```compile_fail
-/// use objc2::rc::AutoreleasePool;
-/// fn needs_sync<T: Sync>() {}
-/// needs_sync::<AutoreleasePool>();
-/// ```
-/// ```compile_fail
-/// use objc2::rc::AutoreleasePool;
-/// fn needs_send<T: Send>() {}
-/// needs_send::<AutoreleasePool>();
-/// ```
-#[cfg(doctest)]
-pub struct AutoreleasePoolNotSendNorSync;
-
 #[cfg(all(debug_assertions, not(feature = "unstable_autoreleasesafe")))]
 thread_local! {
     /// We track the thread's pools to verify that object lifetimes are only

objc2/src/runtime.rs

@@ -613,24 +613,6 @@ impl Object {
     // objc_removeAssociatedObjects
 }
 
-/// ```
-/// use objc2::runtime::Object;
-/// fn needs_nothing<T: ?Sized>() {}
-/// needs_nothing::<Object>();
-/// ```
-/// ```compile_fail
-/// use objc2::runtime::Object;
-/// fn needs_sync<T: ?Sized + Sync>() {}
-/// needs_sync::<Object>();
-/// ```
-/// ```compile_fail
-/// use objc2::runtime::Object;
-/// fn needs_send<T: ?Sized + Send>() {}
-/// needs_send::<Object>();
-/// ```
-#[cfg(doctest)]
-pub struct ObjectNotSendNorSync;
-
 unsafe impl RefEncode for Object {
     const ENCODING_REF: Encoding<'static> = Encoding::Object;
 }

tests/Cargo.toml

@@ -9,12 +9,26 @@ license = "MIT"
 
 build = "build.rs"
 
+[features]
+# Enable UI tests
+#
+# These are not enabled by default because trybuild doesn't pass feature flags
+# (like --features gnustep-1-9) to its cargo invocation, and hence they don't
+# always work.
+#
+# Also, they're slower than most tests.
+ui = ["trybuild"]
+
 [dependencies]
 block2 = { path = "../block2" }
 block-sys = { path = "../block-sys" }
 objc-sys = { path = "../objc-sys" }
 objc2 = { path = "../objc2" }
 objc2-encode = { path = "../objc2-encode" }
+objc2-foundation = { path = "../objc2-foundation" }
+
+# Put here instead of dev-dependencies because we want to make it optional
+trybuild = { version = "1.0", optional = true }
 
 [build-dependencies]
 cc = "1.0"

tests/src/lib.rs

@@ -140,4 +140,11 @@ mod tests {
         let block = block.copy();
         assert_eq!(invoke_large_struct_block(&block, data), new_data);
     }
+
+    #[test]
+    #[cfg(feature = "ui")]
+    fn ui() {
+        let t = trybuild::TestCases::new();
+        t.compile_fail("ui/*.rs");
+    }
 }

tests/ui/autoreleasepool_not_send_sync.rs

@@ -0,0 +1,12 @@
+//! Test that AutoreleasePool is not Send and Sync, because it internally
+//! works with thread locals.
+
+use objc2::rc::AutoreleasePool;
+
+fn needs_sync<T: ?Sized + Sync>() {}
+fn needs_send<T: ?Sized + Send>() {}
+
+fn main() {
+    needs_sync::<AutoreleasePool>();
+    needs_send::<AutoreleasePool>();
+}

tests/ui/autoreleasepool_not_send_sync.stderr

@@ -0,0 +1,57 @@
+error[E0277]: `*mut c_void` cannot be shared between threads safely
+  --> ui/autoreleasepool_not_send_sync.rs:10:5
+   |
+10 |     needs_sync::<AutoreleasePool>();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `*mut c_void` cannot be shared between threads safely
+   |
+   = help: within `AutoreleasePool`, the trait `Sync` is not implemented for `*mut c_void`
+   = note: required because it appears within the type `AutoreleasePool`
+note: required by a bound in `needs_sync`
+  --> ui/autoreleasepool_not_send_sync.rs:6:27
+   |
+6  | fn needs_sync<T: ?Sized + Sync>() {}
+   |                           ^^^^ required by this bound in `needs_sync`
+
+error[E0277]: `*mut UnsafeCell<c_void>` cannot be shared between threads safely
+  --> ui/autoreleasepool_not_send_sync.rs:10:5
+   |
+10 |     needs_sync::<AutoreleasePool>();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `*mut UnsafeCell<c_void>` cannot be shared between threads safely
+   |
+   = help: within `AutoreleasePool`, the trait `Sync` is not implemented for `*mut UnsafeCell<c_void>`
+   = note: required because it appears within the type `PhantomData<*mut UnsafeCell<c_void>>`
+   = note: required because it appears within the type `AutoreleasePool`
+note: required by a bound in `needs_sync`
+  --> ui/autoreleasepool_not_send_sync.rs:6:27
+   |
+6  | fn needs_sync<T: ?Sized + Sync>() {}
+   |                           ^^^^ required by this bound in `needs_sync`
+
+error[E0277]: `*mut c_void` cannot be sent between threads safely
+  --> ui/autoreleasepool_not_send_sync.rs:11:5
+   |
+11 |     needs_send::<AutoreleasePool>();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `*mut c_void` cannot be sent between threads safely
+   |
+   = help: within `AutoreleasePool`, the trait `Send` is not implemented for `*mut c_void`
+   = note: required because it appears within the type `AutoreleasePool`
+note: required by a bound in `needs_send`
+  --> ui/autoreleasepool_not_send_sync.rs:7:27
+   |
+7  | fn needs_send<T: ?Sized + Send>() {}
+   |                           ^^^^ required by this bound in `needs_send`
+
+error[E0277]: `*mut UnsafeCell<c_void>` cannot be sent between threads safely
+  --> ui/autoreleasepool_not_send_sync.rs:11:5
+   |
+11 |     needs_send::<AutoreleasePool>();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `*mut UnsafeCell<c_void>` cannot be sent between threads safely
+   |
+   = help: within `AutoreleasePool`, the trait `Send` is not implemented for `*mut UnsafeCell<c_void>`
+   = note: required because it appears within the type `PhantomData<*mut UnsafeCell<c_void>>`
+   = note: required because it appears within the type `AutoreleasePool`
+note: required by a bound in `needs_send`
+  --> ui/autoreleasepool_not_send_sync.rs:7:27
+   |
+7  | fn needs_send<T: ?Sized + Send>() {}
+   |                           ^^^^ required by this bound in `needs_send`

tests/ui/global_block_not_encode.rs

@@ -0,0 +1,7 @@
+use block2::global_block;
+
+global_block! {
+    pub static BLOCK = |_b: Box<i32>| {};
+}
+
+fn main() {}

tests/ui/global_block_not_encode.stderr

@@ -0,0 +1,12 @@
+error[E0277]: the trait bound `Box<i32>: objc2_encode::encode::Encode` is not satisfied
+ --> ui/global_block_not_encode.rs:3:1
+  |
+3 | / global_block! {
+4 | |     pub static BLOCK = |_b: Box<i32>| {};
+5 | | }
+  | |_^ the trait `objc2_encode::encode::Encode` is not implemented for `Box<i32>`
+  |
+  = note: required because of the requirements on the impl of `objc2_encode::encode::EncodeArguments` for `(Box<i32>,)`
+  = note: required because of the requirements on the impl of `Sync` for `GlobalBlock<(Box<i32>,)>`
+  = note: shared static variables must have a type that implements `Sync`
+  = note: this error originates in the macro `global_block` (in Nightly builds, run with -Z macro-backtrace for more info)

tests/ui/msg_send_no_return_type.rs

@@ -0,0 +1,10 @@
+//! Test that forgetting to annotate the return type fails
+//! See https://github.com/SSheldon/rust-objc/issues/62
+use objc2::{class, msg_send};
+
+fn main() {
+    unsafe {
+        let cls = class!(NSObject);
+        msg_send![cls, new];
+    }
+}

tests/ui/msg_send_no_return_type.stderr

@@ -0,0 +1,7 @@
+error[E0282]: type annotations needed
+ --> ui/msg_send_no_return_type.rs:8:9
+  |
+8 |         msg_send![cls, new];
+  |         ^^^^^^^^^^^^^^^^^^^ consider giving `result` a type
+  |
+  = note: this error originates in the macro `msg_send` (in Nightly builds, run with -Z macro-backtrace for more info)

tests/ui/msg_send_not_encode.rs

@@ -0,0 +1,9 @@
+//! Test that return types that are not `Encode` are not accepted.
+use objc2::{class, msg_send};
+
+fn main() {
+    unsafe {
+        let cls = class!(NSData);
+        let _: Vec<u8> = msg_send![cls, new];
+    }
+}

tests/ui/msg_send_not_encode.stderr

@@ -0,0 +1,12 @@
+error[E0277]: the trait bound `Vec<u8>: Encode` is not satisfied
+   --> ui/msg_send_not_encode.rs:7:26
+    |
+7   |         let _: Vec<u8> = msg_send![cls, new];
+    |                          ^^^^^^^^^^^^^^^^^^^ the trait `Encode` is not implemented for `Vec<u8>`
+    |
+note: required by a bound in `send_message`
+   --> $WORKSPACE/objc2/src/message/mod.rs
+    |
+    |         R: Encode,
+    |            ^^^^^^ required by this bound in `send_message`
+    = note: this error originates in the macro `msg_send` (in Nightly builds, run with -Z macro-backtrace for more info)

tests/ui/msg_send_only_message.rs

@@ -0,0 +1,6 @@
+//! Test that messages can only be sent to objects.
+use objc2::msg_send;
+
+fn main() {
+    unsafe { msg_send![1, new] };
+}

tests/ui/msg_send_only_message.stderr

@@ -0,0 +1,13 @@
+error[E0277]: the trait bound `{integer}: MessageReceiver` is not satisfied
+ --> ui/msg_send_only_message.rs:5:14
+  |
+5 |     unsafe { msg_send![1, new] };
+  |              ^^^^^^^^^^^^^^^^^ the trait `MessageReceiver` is not implemented for `{integer}`
+  |
+  = help: the following implementations were found:
+            <&'a T as MessageReceiver>
+            <&'a mut T as MessageReceiver>
+            <*const T as MessageReceiver>
+            <*mut T as MessageReceiver>
+          and 3 others
+  = note: this error originates in the macro `msg_send` (in Nightly builds, run with -Z macro-backtrace for more info)

tests/ui/nsarray_bound_not_send_sync.rs

@@ -0,0 +1,11 @@
+use objc2::rc::Shared;
+use objc2::runtime::Object;
+use objc2_foundation::NSArray;
+
+fn needs_sync<T: ?Sized + Sync>() {}
+fn needs_send<T: ?Sized + Send>() {}
+
+fn main() {
+    needs_sync::<NSArray<Object, Shared>>();
+    needs_send::<NSArray<Object, Shared>>();
+}