Added bevy_macros_compile_fail_tests crate

Created with compile tests for the Deref/DerefMut derives

Cargo.toml

@@ -16,6 +16,7 @@ rust-version = "1.67.0"
 exclude = [
   "benches",
   "crates/bevy_ecs_compile_fail_tests",
+  "crates/bevy_macros_compile_fail_tests",
   "crates/bevy_reflect_compile_fail_tests",
 ]
 members = [

crates/bevy_macros_compile_fail_tests/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "bevy_macros_compile_fail_tests"
+version = "0.1.0"
+edition = "2021"
+description = "Compile fail tests for Bevy Engine's various macros"
+homepage = "https://bevyengine.org"
+repository = "/~https://github.com/bevyengine/bevy"
+license = "MIT OR Apache-2.0"
+publish = false
+
+[dependencies]
+bevy_derive = { path = "../bevy_derive" }
+trybuild = "1.0.71"

crates/bevy_macros_compile_fail_tests/README.md

@@ -0,0 +1,6 @@
+# Compile fail tests for Bevy macros
+
+This crate is not part of the Bevy workspace in order to not fail `crater` tests for Bevy.
+The tests assert on the exact compiler errors and can easily fail for new Rust versions due to updated compiler errors (e.g. changes in spans).
+
+The `CI` workflow executes these tests on the stable rust toolchain (see [tools/ci](../../tools/ci/src/main.rs)).

crates/bevy_macros_compile_fail_tests/src/lib.rs

@@ -0,0 +1 @@
+// Nothing here, check out the integration tests

crates/bevy_macros_compile_fail_tests/tests/deref_derive.rs

@@ -0,0 +1,6 @@
+#[test]
+fn test() {
+    let t = trybuild::TestCases::new();
+    t.compile_fail("tests/deref_derive/*.fail.rs");
+    t.pass("tests/deref_derive/*.pass.rs");
+}

crates/bevy_macros_compile_fail_tests/tests/deref_derive/invalid_item.fail.rs

@@ -0,0 +1,9 @@
+use bevy_derive::Deref;
+
+#[derive(Deref)]
+struct UnitStruct;
+
+#[derive(Deref)]
+enum Enum {}
+
+fn main() {}

crates/bevy_macros_compile_fail_tests/tests/deref_derive/invalid_item.fail.stderr

@@ -0,0 +1,15 @@
+error: Deref cannot be derived on field-less structs
+ --> tests/deref_derive/invalid_item.fail.rs:3:10
+  |
+3 | #[derive(Deref)]
+  |          ^^^^^
+  |
+  = note: this error originates in the derive macro `Deref` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: Deref can only be derived on structs
+ --> tests/deref_derive/invalid_item.fail.rs:6:10
+  |
+6 | #[derive(Deref)]
+  |          ^^^^^
+  |
+  = note: this error originates in the derive macro `Deref` (in Nightly builds, run with -Z macro-backtrace for more info)

crates/bevy_macros_compile_fail_tests/tests/deref_derive/missing_attribute.fail.rs

@@ -0,0 +1,12 @@
+use bevy_derive::Deref;
+
+#[derive(Deref)]
+struct TupleStruct(usize, String);
+
+#[derive(Deref)]
+struct Struct {
+    foo: usize,
+    bar: String,
+}
+
+fn main() {}

crates/bevy_macros_compile_fail_tests/tests/deref_derive/missing_attribute.fail.stderr

@@ -0,0 +1,15 @@
+error: deriving Deref on multi-field structs requires one field to have the `#[deref]` attribute
+ --> tests/deref_derive/missing_attribute.fail.rs:3:10
+  |
+3 | #[derive(Deref)]
+  |          ^^^^^
+  |
+  = note: this error originates in the derive macro `Deref` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: deriving Deref on multi-field structs requires one field to have the `#[deref]` attribute
+ --> tests/deref_derive/missing_attribute.fail.rs:6:10
+  |
+6 | #[derive(Deref)]
+  |          ^^^^^
+  |
+  = note: this error originates in the derive macro `Deref` (in Nightly builds, run with -Z macro-backtrace for more info)

crates/bevy_macros_compile_fail_tests/tests/deref_derive/multiple_attributes.fail.rs

@@ -0,0 +1,14 @@
+use bevy_derive::Deref;
+
+#[derive(Deref)]
+struct TupleStruct(#[deref] usize, #[deref] String);
+
+#[derive(Deref)]
+struct Struct {
+    #[deref]
+    foo: usize,
+    #[deref]
+    bar: String,
+}
+
+fn main() {}

crates/bevy_macros_compile_fail_tests/tests/deref_derive/multiple_attributes.fail.stderr

@@ -0,0 +1,11 @@
+error: `#[deref]` attribute can only be used on a single field
+ --> tests/deref_derive/multiple_attributes.fail.rs:4:36
+  |
+4 | struct TupleStruct(#[deref] usize, #[deref] String);
+  |                                    ^^^^^^^^
+
+error: `#[deref]` attribute can only be used on a single field
+  --> tests/deref_derive/multiple_attributes.fail.rs:10:5
+   |
+10 |     #[deref]
+   |     ^^^^^^^^

crates/bevy_macros_compile_fail_tests/tests/deref_derive/multiple_fields.pass.rs

@@ -0,0 +1,22 @@
+use bevy_derive::Deref;
+
+#[derive(Deref)]
+struct TupleStruct(usize, #[deref] String);
+
+#[derive(Deref)]
+struct Struct {
+    foo: usize,
+    #[deref]
+    bar: String,
+}
+
+fn main() {
+    let value = TupleStruct(123, "Hello world!".to_string());
+    let _: &String = &*value;
+
+    let value = Struct {
+        foo: 123,
+        bar: "Hello world!".to_string(),
+    };
+    let _: &String = &*value;
+}

crates/bevy_macros_compile_fail_tests/tests/deref_mut_derive.rs

@@ -0,0 +1,6 @@
+#[test]
+fn test() {
+    let t = trybuild::TestCases::new();
+    t.compile_fail("tests/deref_mut_derive/*.fail.rs");
+    t.pass("tests/deref_mut_derive/*.pass.rs");
+}

crates/bevy_macros_compile_fail_tests/tests/deref_mut_derive/invalid_item.fail.rs

@@ -0,0 +1,9 @@
+use bevy_derive::DerefMut;
+
+#[derive(DerefMut)]
+struct UnitStruct;
+
+#[derive(DerefMut)]
+enum Enum {}
+
+fn main() {}

crates/bevy_macros_compile_fail_tests/tests/deref_mut_derive/invalid_item.fail.stderr

@@ -0,0 +1,15 @@
+error: DerefMut cannot be derived on field-less structs
+ --> tests/deref_mut_derive/invalid_item.fail.rs:3:10
+  |
+3 | #[derive(DerefMut)]
+  |          ^^^^^^^^
+  |
+  = note: this error originates in the derive macro `DerefMut` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: DerefMut can only be derived on structs
+ --> tests/deref_mut_derive/invalid_item.fail.rs:6:10
+  |
+6 | #[derive(DerefMut)]
+  |          ^^^^^^^^
+  |
+  = note: this error originates in the derive macro `DerefMut` (in Nightly builds, run with -Z macro-backtrace for more info)

crates/bevy_macros_compile_fail_tests/tests/deref_mut_derive/mismatched_target_type.fail.rs

@@ -0,0 +1,30 @@
+use bevy_derive::DerefMut;
+use std::ops::Deref;
+
+#[derive(DerefMut)]
+struct TupleStruct(#[deref] usize, String);
+
+impl Deref for TupleStruct {
+    type Target = String;
+
+    fn deref(&self) -> &Self::Target {
+        &self.1
+    }
+}
+
+#[derive(DerefMut)]
+struct Struct {
+    #[deref]
+    foo: usize,
+    bar: String,
+}
+
+impl Deref for Struct {
+    type Target = String;
+
+    fn deref(&self) -> &Self::Target {
+        &self.bar
+    }
+}
+
+fn main() {}

crates/bevy_macros_compile_fail_tests/tests/deref_mut_derive/mismatched_target_type.fail.stderr

@@ -0,0 +1,25 @@
+error[E0308]: mismatched types
+ --> tests/deref_mut_derive/mismatched_target_type.fail.rs:4:10
+  |
+4 | #[derive(DerefMut)]
+  |          ^^^^^^^^
+  |          |
+  |          expected `&mut String`, found `&mut usize`
+  |          expected `&mut String` because of return type
+  |
+  = note: expected mutable reference `&mut String`
+             found mutable reference `&mut usize`
+  = note: this error originates in the derive macro `DerefMut` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0308]: mismatched types
+  --> tests/deref_mut_derive/mismatched_target_type.fail.rs:15:10
+   |
+15 | #[derive(DerefMut)]
+   |          ^^^^^^^^
+   |          |
+   |          expected `&mut String`, found `&mut usize`
+   |          expected `&mut String` because of return type
+   |
+   = note: expected mutable reference `&mut String`
+              found mutable reference `&mut usize`
+   = note: this error originates in the derive macro `DerefMut` (in Nightly builds, run with -Z macro-backtrace for more info)

crates/bevy_macros_compile_fail_tests/tests/deref_mut_derive/missing_attribute.fail.rs

@@ -0,0 +1,29 @@
+use bevy_derive::DerefMut;
+use std::ops::Deref;
+
+#[derive(DerefMut)]
+struct TupleStruct(usize, String);
+
+impl Deref for TupleStruct {
+    type Target = String;
+
+    fn deref(&self) -> &Self::Target {
+        &self.1
+    }
+}
+
+#[derive(DerefMut)]
+struct Struct {
+    foo: usize,
+    bar: String,
+}
+
+impl Deref for Struct {
+    type Target = String;
+
+    fn deref(&self) -> &Self::Target {
+        &self.bar
+    }
+}
+
+fn main() {}

crates/bevy_macros_compile_fail_tests/tests/deref_mut_derive/missing_attribute.fail.stderr

@@ -0,0 +1,15 @@
+error: deriving DerefMut on multi-field structs requires one field to have the `#[deref]` attribute
+ --> tests/deref_mut_derive/missing_attribute.fail.rs:4:10
+  |
+4 | #[derive(DerefMut)]
+  |          ^^^^^^^^
+  |
+  = note: this error originates in the derive macro `DerefMut` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: deriving DerefMut on multi-field structs requires one field to have the `#[deref]` attribute
+  --> tests/deref_mut_derive/missing_attribute.fail.rs:15:10
+   |
+15 | #[derive(DerefMut)]
+   |          ^^^^^^^^
+   |
+   = note: this error originates in the derive macro `DerefMut` (in Nightly builds, run with -Z macro-backtrace for more info)

crates/bevy_macros_compile_fail_tests/tests/deref_mut_derive/missing_deref.fail.rs

@@ -0,0 +1,13 @@
+use bevy_derive::DerefMut;
+
+#[derive(DerefMut)]
+struct TupleStruct(usize, #[deref] String);
+
+#[derive(DerefMut)]
+struct Struct {
+    foo: usize,
+    #[deref]
+    bar: String,
+}
+
+fn main() {}

crates/bevy_macros_compile_fail_tests/tests/deref_mut_derive/missing_deref.fail.stderr

@@ -0,0 +1,39 @@
+error[E0277]: the trait bound `TupleStruct: Deref` is not satisfied
+ --> tests/deref_mut_derive/missing_deref.fail.rs:4:8
+  |
+4 | struct TupleStruct(usize, #[deref] String);
+  |        ^^^^^^^^^^^ the trait `Deref` is not implemented for `TupleStruct`
+  |
+note: required by a bound in `DerefMut`
+ --> $RUST/core/src/ops/deref.rs
+  |
+  | pub trait DerefMut: Deref {
+  |                     ^^^^^ required by this bound in `DerefMut`
+
+error[E0277]: the trait bound `Struct: Deref` is not satisfied
+ --> tests/deref_mut_derive/missing_deref.fail.rs:7:8
+  |
+7 | struct Struct {
+  |        ^^^^^^ the trait `Deref` is not implemented for `Struct`
+  |
+note: required by a bound in `DerefMut`
+ --> $RUST/core/src/ops/deref.rs
+  |
+  | pub trait DerefMut: Deref {
+  |                     ^^^^^ required by this bound in `DerefMut`
+
+error[E0277]: the trait bound `TupleStruct: Deref` is not satisfied
+ --> tests/deref_mut_derive/missing_deref.fail.rs:3:10
+  |
+3 | #[derive(DerefMut)]
+  |          ^^^^^^^^ the trait `Deref` is not implemented for `TupleStruct`
+  |
+  = note: this error originates in the derive macro `DerefMut` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0277]: the trait bound `Struct: Deref` is not satisfied
+ --> tests/deref_mut_derive/missing_deref.fail.rs:6:10
+  |
+6 | #[derive(DerefMut)]
+  |          ^^^^^^^^ the trait `Deref` is not implemented for `Struct`
+  |
+  = note: this error originates in the derive macro `DerefMut` (in Nightly builds, run with -Z macro-backtrace for more info)

crates/bevy_macros_compile_fail_tests/tests/deref_mut_derive/multiple_attributes.fail.rs

@@ -0,0 +1,31 @@
+use bevy_derive::DerefMut;
+use std::ops::Deref;
+
+#[derive(DerefMut)]
+struct TupleStruct(#[deref] usize, #[deref] String);
+
+impl Deref for TupleStruct {
+    type Target = String;
+
+    fn deref(&self) -> &Self::Target {
+        &self.1
+    }
+}
+
+#[derive(DerefMut)]
+struct Struct {
+    #[deref]
+    foo: usize,
+    #[deref]
+    bar: String,
+}
+
+impl Deref for Struct {
+    type Target = String;
+
+    fn deref(&self) -> &Self::Target {
+        &self.bar
+    }
+}
+
+fn main() {}

crates/bevy_macros_compile_fail_tests/tests/deref_mut_derive/multiple_attributes.fail.stderr

@@ -0,0 +1,11 @@
+error: `#[deref]` attribute can only be used on a single field
+ --> tests/deref_mut_derive/multiple_attributes.fail.rs:5:36
+  |
+5 | struct TupleStruct(#[deref] usize, #[deref] String);
+  |                                    ^^^^^^^^
+
+error: `#[deref]` attribute can only be used on a single field
+  --> tests/deref_mut_derive/multiple_attributes.fail.rs:19:5
+   |
+19 |     #[deref]
+   |     ^^^^^^^^