Revert "chore: disable warnings in old CI (#4691)"

This reverts commit b24df49a9d so we can
merge the CHANGELOG changes in #4691 into master.

tests-build/tests/fail/macros_core_no_default.rs

@@ -0,0 +1,6 @@
+use tests_build::tokio;
+
+#[tokio::main]
+async fn my_fn() {}
+
+fn main() {}

tests-build/tests/fail/macros_core_no_default.stderr

@@ -0,0 +1,7 @@
+error: The default runtime flavor is `multi_thread`, but the `rt-multi-thread` feature is disabled.
+ --> $DIR/macros_core_no_default.rs:3:1
+  |
+3 | #[tokio::main]
+  | ^^^^^^^^^^^^^^
+  |
+  = note: this error originates in the attribute macro `tokio::main` (in Nightly builds, run with -Z macro-backtrace for more info)

tests-build/tests/fail/macros_dead_code.rs

@@ -0,0 +1,8 @@
+#![deny(dead_code)]
+
+use tests_build::tokio;
+
+#[tokio::main]
+async fn f() {}
+
+fn main() {}

tests-build/tests/fail/macros_dead_code.stderr

@@ -0,0 +1,11 @@
+error: function is never used: `f`
+ --> $DIR/macros_dead_code.rs:6:10
+  |
+6 | async fn f() {}
+  |          ^
+  |
+note: the lint level is defined here
+ --> $DIR/macros_dead_code.rs:1:9
+  |
+1 | #![deny(dead_code)]
+  |         ^^^^^^^^^

tests-build/tests/fail/macros_invalid_input.rs

@@ -0,0 +1,40 @@
+use tests_build::tokio;
+
+#[tokio::main]
+fn main_is_not_async() {}
+
+#[tokio::main(foo)]
+async fn main_attr_has_unknown_args() {}
+
+#[tokio::main(threadpool::bar)]
+async fn main_attr_has_path_args() {}
+
+#[tokio::test]
+fn test_is_not_async() {}
+
+#[tokio::test(foo)]
+async fn test_attr_has_args() {}
+
+#[tokio::test(foo = 123)]
+async fn test_unexpected_attr() {}
+
+#[tokio::test(flavor = 123)]
+async fn test_flavor_not_string() {}
+
+#[tokio::test(flavor = "foo")]
+async fn test_unknown_flavor() {}
+
+#[tokio::test(flavor = "multi_thread", start_paused = false)]
+async fn test_multi_thread_with_start_paused() {}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = "foo")]
+async fn test_worker_threads_not_int() {}
+
+#[tokio::test(flavor = "current_thread", worker_threads = 4)]
+async fn test_worker_threads_and_current_thread() {}
+
+#[tokio::test]
+#[test]
+async fn test_has_second_test_attr() {}
+
+fn main() {}

tests-build/tests/fail/macros_invalid_input.stderr

@@ -0,0 +1,71 @@
+error: the `async` keyword is missing from the function declaration
+ --> $DIR/macros_invalid_input.rs:4:1
+  |
+4 | fn main_is_not_async() {}
+  | ^^
+
+error: Unknown attribute foo is specified; expected one of: `flavor`, `worker_threads`, `start_paused`
+ --> $DIR/macros_invalid_input.rs:6:15
+  |
+6 | #[tokio::main(foo)]
+  |               ^^^
+
+error: Must have specified ident
+ --> $DIR/macros_invalid_input.rs:9:15
+  |
+9 | #[tokio::main(threadpool::bar)]
+  |               ^^^^^^^^^^^^^^^
+
+error: the `async` keyword is missing from the function declaration
+  --> $DIR/macros_invalid_input.rs:13:1
+   |
+13 | fn test_is_not_async() {}
+   | ^^
+
+error: Unknown attribute foo is specified; expected one of: `flavor`, `worker_threads`, `start_paused`
+  --> $DIR/macros_invalid_input.rs:15:15
+   |
+15 | #[tokio::test(foo)]
+   |               ^^^
+
+error: Unknown attribute foo is specified; expected one of: `flavor`, `worker_threads`, `start_paused`
+  --> $DIR/macros_invalid_input.rs:18:15
+   |
+18 | #[tokio::test(foo = 123)]
+   |               ^^^^^^^^^
+
+error: Failed to parse value of `flavor` as string.
+  --> $DIR/macros_invalid_input.rs:21:24
+   |
+21 | #[tokio::test(flavor = 123)]
+   |                        ^^^
+
+error: No such runtime flavor `foo`. The runtime flavors are `current_thread` and `multi_thread`.
+  --> $DIR/macros_invalid_input.rs:24:24
+   |
+24 | #[tokio::test(flavor = "foo")]
+   |                        ^^^^^
+
+error: The `start_paused` option requires the `current_thread` runtime flavor. Use `#[tokio::test(flavor = "current_thread")]`
+  --> $DIR/macros_invalid_input.rs:27:55
+   |
+27 | #[tokio::test(flavor = "multi_thread", start_paused = false)]
+   |                                                       ^^^^^
+
+error: Failed to parse value of `worker_threads` as integer.
+  --> $DIR/macros_invalid_input.rs:30:57
+   |
+30 | #[tokio::test(flavor = "multi_thread", worker_threads = "foo")]
+   |                                                         ^^^^^
+
+error: The `worker_threads` option requires the `multi_thread` runtime flavor. Use `#[tokio::test(flavor = "multi_thread")]`
+  --> $DIR/macros_invalid_input.rs:33:59
+   |
+33 | #[tokio::test(flavor = "current_thread", worker_threads = 4)]
+   |                                                           ^
+
+error: second test attribute is supplied
+  --> $DIR/macros_invalid_input.rs:37:1
+   |
+37 | #[test]
+   | ^^^^^^^

tests-build/tests/fail/macros_type_mismatch.rs

@@ -0,0 +1,26 @@
+use tests_build::tokio;
+
+#[tokio::main]
+async fn missing_semicolon_or_return_type() {
+    Ok(())
+}
+
+#[tokio::main]
+async fn missing_return_type() {
+    return Ok(());
+}
+
+#[tokio::main]
+async fn extra_semicolon() -> Result<(), ()> {
+    /* TODO(taiki-e): help message still wrong
+    help: try using a variant of the expected enum
+       |
+    23 |     Ok(Ok(());)
+       |
+    23 |     Err(Ok(());)
+       |
+    */
+    Ok(());
+}
+
+fn main() {}

tests-build/tests/fail/macros_type_mismatch.stderr

@@ -0,0 +1,45 @@
+error[E0308]: mismatched types
+ --> $DIR/macros_type_mismatch.rs:5:5
+  |
+5 |     Ok(())
+  |     ^^^^^^ expected `()`, found enum `Result`
+  |
+  = note: expected unit type `()`
+                  found enum `Result<(), _>`
+help: consider using a semicolon here
+  |
+5 |     Ok(());
+  |           +
+help: try adding a return type
+  |
+4 | async fn missing_semicolon_or_return_type() -> Result<(), _> {
+  |                                             ++++++++++++++++
+
+error[E0308]: mismatched types
+  --> $DIR/macros_type_mismatch.rs:10:5
+   |
+9  | async fn missing_return_type() {
+   |                                - help: try adding a return type: `-> Result<(), _>`
+10 |     return Ok(());
+   |     ^^^^^^^^^^^^^^ expected `()`, found enum `Result`
+   |
+   = note: expected unit type `()`
+                   found enum `Result<(), _>`
+
+error[E0308]: mismatched types
+  --> $DIR/macros_type_mismatch.rs:23:5
+   |
+14 | async fn extra_semicolon() -> Result<(), ()> {
+   |                               -------------- expected `Result<(), ()>` because of return type
+...
+23 |     Ok(());
+   |     ^^^^^^^ expected enum `Result`, found `()`
+   |
+   = note:   expected enum `Result<(), ()>`
+           found unit type `()`
+help: try using a variant of the expected enum
+   |
+23 |     Ok(Ok(());)
+   |
+23 |     Err(Ok(());)
+   |

tests-build/tests/macros.rs

@@ -0,0 +1,27 @@
+#[test]
+fn compile_fail_full() {
+    let t = trybuild::TestCases::new();
+
+    #[cfg(feature = "full")]
+    t.pass("tests/pass/forward_args_and_output.rs");
+
+    #[cfg(feature = "full")]
+    t.pass("tests/pass/macros_main_return.rs");
+
+    #[cfg(feature = "full")]
+    t.pass("tests/pass/macros_main_loop.rs");
+
+    #[cfg(feature = "full")]
+    t.compile_fail("tests/fail/macros_invalid_input.rs");
+
+    #[cfg(feature = "full")]
+    t.compile_fail("tests/fail/macros_dead_code.rs");
+
+    #[cfg(feature = "full")]
+    t.compile_fail("tests/fail/macros_type_mismatch.rs");
+
+    #[cfg(all(feature = "rt", not(feature = "full")))]
+    t.compile_fail("tests/fail/macros_core_no_default.rs");
+
+    drop(t);
+}

tests-build/tests/macros_clippy.rs

@@ -0,0 +1,7 @@
+#[cfg(feature = "full")]
+#[tokio::test]
+async fn test_with_semicolon_without_return_type() {
+    #![deny(clippy::semicolon_if_nothing_returned)]
+
+    dbg!(0);
+}

tests-build/tests/pass/forward_args_and_output.rs

@@ -0,0 +1,13 @@
+use tests_build::tokio;
+
+fn main() {}
+
+// arguments and output type is forwarded so other macros can access them
+
+#[tokio::test]
+async fn test_fn_has_args(_x: u8) {}
+
+#[tokio::test]
+async fn test_has_output() -> Result<(), Box<dyn std::error::Error>> {
+    Ok(())
+}

tests-build/tests/pass/macros_main_loop.rs

@@ -0,0 +1,14 @@
+use tests_build::tokio;
+
+#[tokio::main]
+async fn main() -> Result<(), ()> {
+    loop {
+        if !never() {
+            return Ok(());
+        }
+    }
+}
+
+fn never() -> bool {
+    std::time::Instant::now() > std::time::Instant::now()
+}

tests-build/tests/pass/macros_main_return.rs

@@ -0,0 +1,6 @@
+use tests_build::tokio;
+
+#[tokio::main]
+async fn main() -> Result<(), ()> {
+    return Ok(());
+}