From 75fa9f6decc089ae47beeef1db04aec4ed514bcc Mon Sep 17 00:00:00 2001
From: Alex Crichton <alex@alexcrichton.com>
Date: Wed, 6 Mar 2024 12:19:20 -0800
Subject: [PATCH] compiletest: Add a `//@ needs-threads` directive

This commit is extracted from #122036 and adds a new directive to the
`compiletest` test runner, `//@ needs-threads`. This is intended to
capture the need that a target must implement threading to execute a
specific test, typically one that uses `std::thread`. This is primarily
done for WebAssembly targets which currently do not have threads by
default. This enables transitioning a lot of `//@ ignore-wasm*`-style
ignores into a more self-documenting `//@ needs-threads` directive.
Additionally the `wasm32-wasi-preview1-threads` target, for example,
does actually have threads, but isn't tested in CI at this time. This
change enables running these tests for that target, but not other wasm
targets.
---
 src/tools/compiletest/src/common.rs           |  9 +++++++++
 src/tools/compiletest/src/header.rs           |  1 +
 src/tools/compiletest/src/header/needs.rs     |  5 +++++
 src/tools/compiletest/src/header/tests.rs     | 20 +++++++++++++++++++
 tests/codegen/cffi/c-variadic.rs              |  2 +-
 tests/ui/abi/extern/extern-call-deep2.rs      |  2 +-
 tests/ui/abi/extern/extern-call-scrub.rs      |  2 +-
 .../ui/abi/foreign/foreign-call-no-runtime.rs |  2 +-
 tests/ui/box/unit/unique-send-2.rs            |  2 +-
 tests/ui/codegen/init-large-type.rs           |  3 +--
 tests/ui/codegen/issue-28950.rs               |  2 +-
 tests/ui/coroutine/smoke.rs                   |  2 +-
 tests/ui/cross-crate/cci_capture_clause.rs    |  2 +-
 tests/ui/hashmap/hashmap-memory.rs            |  2 +-
 tests/ui/issues/issue-16560.rs                |  2 +-
 tests/ui/issues/issue-21291.rs                |  2 +-
 tests/ui/issues/issue-22864-2.rs              |  2 +-
 tests/ui/issues/issue-59020.rs                |  2 +-
 tests/ui/logging-only-prints-once.rs          |  2 +-
 tests/ui/lto/lto-still-runs-thread-dtors.rs   |  2 +-
 .../macro-with-braces-in-expr-position.rs     |  2 +-
 .../moves-based-on-type-capture-clause.rs     |  2 +-
 tests/ui/panics/panic-handler-chain.rs        |  3 +--
 tests/ui/panics/panic-task-name-none.rs       |  2 +-
 tests/ui/panics/panic-task-name-owned.rs      |  2 +-
 .../process-termination-blocking-io.rs        |  2 +-
 .../process-termination-simple.rs             |  2 +-
 tests/ui/structs-enums/ivec-tag.rs            |  2 +-
 tests/ui/test-attrs/test-filter-multiple.rs   |  2 +-
 tests/ui/test-attrs/test-type.rs              |  2 +-
 tests/ui/thread-local/tls.rs                  |  2 +-
 .../threads-sendsync/child-outlives-parent.rs |  2 +-
 .../threads-sendsync/clone-with-exterior.rs   |  2 +-
 tests/ui/threads-sendsync/comm.rs             |  4 ++--
 .../ui/threads-sendsync/eprint-on-tls-drop.rs |  2 +-
 tests/ui/threads-sendsync/issue-24313.rs      |  2 +-
 tests/ui/threads-sendsync/issue-29488.rs      |  2 +-
 tests/ui/threads-sendsync/issue-43733-2.rs    |  2 +-
 tests/ui/threads-sendsync/issue-43733.rs      |  2 +-
 tests/ui/threads-sendsync/issue-4446.rs       |  2 +-
 tests/ui/threads-sendsync/issue-4448.rs       |  2 +-
 tests/ui/threads-sendsync/issue-8827.rs       |  2 +-
 tests/ui/threads-sendsync/issue-9396.rs       |  2 +-
 tests/ui/threads-sendsync/mpsc_stress.rs      |  2 +-
 tests/ui/threads-sendsync/send-resource.rs    |  2 +-
 .../sendfn-spawn-with-fn-arg.rs               |  2 +-
 tests/ui/threads-sendsync/spawn-fn.rs         |  2 +-
 tests/ui/threads-sendsync/spawn-types.rs      |  2 +-
 tests/ui/threads-sendsync/spawn.rs            |  2 +-
 tests/ui/threads-sendsync/spawn2.rs           |  2 +-
 .../threads-sendsync/spawning-with-debug.rs   |  2 +-
 tests/ui/threads-sendsync/task-comm-0.rs      |  2 +-
 tests/ui/threads-sendsync/task-comm-1.rs      |  2 +-
 tests/ui/threads-sendsync/task-comm-10.rs     |  2 +-
 tests/ui/threads-sendsync/task-comm-11.rs     |  2 +-
 tests/ui/threads-sendsync/task-comm-12.rs     |  2 +-
 tests/ui/threads-sendsync/task-comm-13.rs     |  2 +-
 tests/ui/threads-sendsync/task-comm-14.rs     |  2 +-
 tests/ui/threads-sendsync/task-comm-15.rs     |  2 +-
 tests/ui/threads-sendsync/task-comm-17.rs     |  2 +-
 tests/ui/threads-sendsync/task-comm-3.rs      |  2 +-
 tests/ui/threads-sendsync/task-comm-7.rs      |  2 +-
 tests/ui/threads-sendsync/task-comm-9.rs      |  2 +-
 tests/ui/threads-sendsync/task-life-0.rs      |  2 +-
 .../ui/threads-sendsync/task-spawn-barefn.rs  |  2 +-
 .../task-spawn-move-and-copy.rs               |  2 +-
 tests/ui/threads-sendsync/task-stderr.rs      |  2 +-
 tests/ui/threads-sendsync/tcp-stress.rs       |  2 +-
 .../test-tasks-invalid-value.rs               |  2 +-
 tests/ui/threads-sendsync/threads.rs          |  2 +-
 .../tls-dtors-are-run-in-a-static-binary.rs   |  2 +-
 tests/ui/threads-sendsync/tls-init-on-init.rs |  2 +-
 tests/ui/threads-sendsync/tls-try-with.rs     |  2 +-
 tests/ui/threads-sendsync/unwind-resource.rs  |  2 +-
 tests/ui/threads-sendsync/yield.rs            |  2 +-
 tests/ui/threads-sendsync/yield1.rs           |  2 +-
 tests/ui/traits/bound/in-arc.rs               |  2 +-
 77 files changed, 109 insertions(+), 76 deletions(-)

diff --git a/src/tools/compiletest/src/common.rs b/src/tools/compiletest/src/common.rs
index 8c50bcd5b61..06d8f099c33 100644
--- a/src/tools/compiletest/src/common.rs
+++ b/src/tools/compiletest/src/common.rs
@@ -451,6 +451,15 @@ pub fn can_unwind(&self) -> bool {
         self.target_cfg().panic == PanicStrategy::Unwind
     }
 
+    pub fn has_threads(&self) -> bool {
+        // Wasm targets don't have threads unless `-threads` is in the target
+        // name, such as `wasm32-wasip1-threads`.
+        if self.target.starts_with("wasm") {
+            return self.target.contains("threads");
+        }
+        true
+    }
+
     pub fn has_asm_support(&self) -> bool {
         static ASM_SUPPORTED_ARCHS: &[&str] = &[
             "x86", "x86_64", "arm", "aarch64", "riscv32",
diff --git a/src/tools/compiletest/src/header.rs b/src/tools/compiletest/src/header.rs
index 6de445a5783..f15761354f7 100644
--- a/src/tools/compiletest/src/header.rs
+++ b/src/tools/compiletest/src/header.rs
@@ -787,6 +787,7 @@ pub fn line_directive<'line>(
     "needs-sanitizer-shadow-call-stack",
     "needs-sanitizer-support",
     "needs-sanitizer-thread",
+    "needs-threads",
     "needs-unwind",
     "needs-xray",
     "no-prefer-dynamic",
diff --git a/src/tools/compiletest/src/header/needs.rs b/src/tools/compiletest/src/header/needs.rs
index 39786588150..d7c74038aea 100644
--- a/src/tools/compiletest/src/header/needs.rs
+++ b/src/tools/compiletest/src/header/needs.rs
@@ -84,6 +84,11 @@ pub(super) fn handle_needs(
             condition: config.run_enabled(),
             ignore_reason: "ignored when running the resulting test binaries is disabled",
         },
+        Need {
+            name: "needs-threads",
+            condition: config.has_threads(),
+            ignore_reason: "ignored on targets without threading support",
+        },
         Need {
             name: "needs-unwind",
             condition: config.can_unwind(),
diff --git a/src/tools/compiletest/src/header/tests.rs b/src/tools/compiletest/src/header/tests.rs
index eff76a38d2e..815ac3839df 100644
--- a/src/tools/compiletest/src/header/tests.rs
+++ b/src/tools/compiletest/src/header/tests.rs
@@ -592,3 +592,23 @@ fn ignore_mode() {
         assert!(!check_ignore(&config, &format!("//@ ignore-mode-{other}")));
     }
 }
+
+#[test]
+fn threads_support() {
+    let threads = [
+        ("x86_64-unknown-linux-gnu", true),
+        ("aarch64-apple-darwin", true),
+        ("wasm32-unknown-unknown", false),
+        ("wasm64-unknown-unknown", false),
+        #[cfg(not(bootstrap))]
+        ("wasm32-wasip1", false),
+        #[cfg(not(bootstrap))]
+        ("wasm32-wasip1-threads", true),
+        ("wasm32-wasi-preview1-threads", true),
+    ];
+    for (target, has_threads) in threads {
+        let config = cfg().target(target).build();
+        assert_eq!(config.has_threads(), has_threads);
+        assert_eq!(check_ignore(&config, "//@ needs-threads"), !has_threads)
+    }
+}
diff --git a/tests/codegen/cffi/c-variadic.rs b/tests/codegen/cffi/c-variadic.rs
index 74aed36a8a1..914d1623ed2 100644
--- a/tests/codegen/cffi/c-variadic.rs
+++ b/tests/codegen/cffi/c-variadic.rs
@@ -1,4 +1,4 @@
-//@ ignore-wasm32-bare compiled with panic=abort by default
+//@ needs-unwind
 //@ compile-flags: -C no-prepopulate-passes -Copt-level=0
 //
 
diff --git a/tests/ui/abi/extern/extern-call-deep2.rs b/tests/ui/abi/extern/extern-call-deep2.rs
index 80c492e3022..c021bc22348 100644
--- a/tests/ui/abi/extern/extern-call-deep2.rs
+++ b/tests/ui/abi/extern/extern-call-deep2.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 #![allow(unused_must_use)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 #![feature(rustc_private)]
 
 extern crate libc;
diff --git a/tests/ui/abi/extern/extern-call-scrub.rs b/tests/ui/abi/extern/extern-call-scrub.rs
index 873f5d2e774..7edf8975ad8 100644
--- a/tests/ui/abi/extern/extern-call-scrub.rs
+++ b/tests/ui/abi/extern/extern-call-scrub.rs
@@ -4,7 +4,7 @@
 // make sure the stack pointers are maintained properly in both
 // directions
 
-//@ ignore-emscripten no threads support
+//@ needs-threads
 #![feature(rustc_private)]
 
 extern crate libc;
diff --git a/tests/ui/abi/foreign/foreign-call-no-runtime.rs b/tests/ui/abi/foreign/foreign-call-no-runtime.rs
index 7f847d55721..42d8d7b1d25 100644
--- a/tests/ui/abi/foreign/foreign-call-no-runtime.rs
+++ b/tests/ui/abi/foreign/foreign-call-no-runtime.rs
@@ -1,5 +1,5 @@
 //@ run-pass
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 #![feature(rustc_private)]
 
diff --git a/tests/ui/box/unit/unique-send-2.rs b/tests/ui/box/unit/unique-send-2.rs
index 20474fee4d8..d3cbeefab37 100644
--- a/tests/ui/box/unit/unique-send-2.rs
+++ b/tests/ui/box/unit/unique-send-2.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 #![allow(unused_must_use)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::sync::mpsc::{channel, Sender};
 use std::thread;
diff --git a/tests/ui/codegen/init-large-type.rs b/tests/ui/codegen/init-large-type.rs
index 34b40693ab1..b9fc6612e16 100644
--- a/tests/ui/codegen/init-large-type.rs
+++ b/tests/ui/codegen/init-large-type.rs
@@ -7,8 +7,7 @@
 // optimisation.
 
 //@ pretty-expanded FIXME #23616
-//@ ignore-emscripten no threads support
-
+//@ needs-threads
 #![feature(intrinsics)]
 
 use std::{mem, thread};
diff --git a/tests/ui/codegen/issue-28950.rs b/tests/ui/codegen/issue-28950.rs
index 8e55172af6d..0a706c588d5 100644
--- a/tests/ui/codegen/issue-28950.rs
+++ b/tests/ui/codegen/issue-28950.rs
@@ -1,5 +1,5 @@
 //@ run-pass
-//@ ignore-emscripten no threads
+//@ needs-threads
 //@ compile-flags: -O
 
 // Tests that the `vec!` macro does not overflow the stack when it is
diff --git a/tests/ui/coroutine/smoke.rs b/tests/ui/coroutine/smoke.rs
index 0ed56982c9b..17d98a52a1c 100644
--- a/tests/ui/coroutine/smoke.rs
+++ b/tests/ui/coroutine/smoke.rs
@@ -3,7 +3,7 @@
 //@ revisions: default nomiropt
 //@[nomiropt]compile-flags: -Z mir-opt-level=0
 
-//@ ignore-emscripten no threads support
+//@ needs-threads
 //@ compile-flags: --test
 
 #![feature(coroutines, coroutine_trait)]
diff --git a/tests/ui/cross-crate/cci_capture_clause.rs b/tests/ui/cross-crate/cci_capture_clause.rs
index 99736ad185d..73e1020d7cf 100644
--- a/tests/ui/cross-crate/cci_capture_clause.rs
+++ b/tests/ui/cross-crate/cci_capture_clause.rs
@@ -5,7 +5,7 @@
 // that use capture clauses.
 
 //@ pretty-expanded FIXME #23616
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 extern crate cci_capture_clause;
 
diff --git a/tests/ui/hashmap/hashmap-memory.rs b/tests/ui/hashmap/hashmap-memory.rs
index 0b1e09f5344..6db5d2e7bef 100644
--- a/tests/ui/hashmap/hashmap-memory.rs
+++ b/tests/ui/hashmap/hashmap-memory.rs
@@ -4,7 +4,7 @@
 #![allow(non_camel_case_types)]
 #![allow(dead_code)]
 #![allow(unused_mut)]
-//@ ignore-emscripten No support for threads
+//@ needs-threads
 
 /**
    A somewhat reduced test case to expose some Valgrind issues.
diff --git a/tests/ui/issues/issue-16560.rs b/tests/ui/issues/issue-16560.rs
index 37b536e644d..d9a7aa9101d 100644
--- a/tests/ui/issues/issue-16560.rs
+++ b/tests/ui/issues/issue-16560.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 #![allow(unused_variables)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 use std::mem;
diff --git a/tests/ui/issues/issue-21291.rs b/tests/ui/issues/issue-21291.rs
index 357d5520028..06f50ac6996 100644
--- a/tests/ui/issues/issue-21291.rs
+++ b/tests/ui/issues/issue-21291.rs
@@ -1,5 +1,5 @@
 //@ run-pass
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 // Regression test for unwrapping the result of `join`, issue #21291
 
diff --git a/tests/ui/issues/issue-22864-2.rs b/tests/ui/issues/issue-22864-2.rs
index 1b702f4f509..d98dbeda46b 100644
--- a/tests/ui/issues/issue-22864-2.rs
+++ b/tests/ui/issues/issue-22864-2.rs
@@ -1,5 +1,5 @@
 //@ run-pass
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 pub fn main() {
     let f = || || 0;
diff --git a/tests/ui/issues/issue-59020.rs b/tests/ui/issues/issue-59020.rs
index 5692afe811e..2a34ba52b88 100644
--- a/tests/ui/issues/issue-59020.rs
+++ b/tests/ui/issues/issue-59020.rs
@@ -1,6 +1,6 @@
 //@ edition:2018
 //@ run-pass
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 use std::time::Duration;
diff --git a/tests/ui/logging-only-prints-once.rs b/tests/ui/logging-only-prints-once.rs
index 75ef0a274ee..5377d5eeae2 100644
--- a/tests/ui/logging-only-prints-once.rs
+++ b/tests/ui/logging-only-prints-once.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 //@ ignore-windows
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::cell::Cell;
 use std::fmt;
diff --git a/tests/ui/lto/lto-still-runs-thread-dtors.rs b/tests/ui/lto/lto-still-runs-thread-dtors.rs
index a93d7cf35cc..504923a93c2 100644
--- a/tests/ui/lto/lto-still-runs-thread-dtors.rs
+++ b/tests/ui/lto/lto-still-runs-thread-dtors.rs
@@ -1,7 +1,7 @@
 //@ run-pass
 //@ compile-flags: -C lto
 //@ no-prefer-dynamic
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 
diff --git a/tests/ui/macros/macro-with-braces-in-expr-position.rs b/tests/ui/macros/macro-with-braces-in-expr-position.rs
index febfa7241f2..4607349e963 100644
--- a/tests/ui/macros/macro-with-braces-in-expr-position.rs
+++ b/tests/ui/macros/macro-with-braces-in-expr-position.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 #![allow(unused_must_use)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 
diff --git a/tests/ui/moves/moves-based-on-type-capture-clause.rs b/tests/ui/moves/moves-based-on-type-capture-clause.rs
index baf52ffb515..46759f66468 100644
--- a/tests/ui/moves/moves-based-on-type-capture-clause.rs
+++ b/tests/ui/moves/moves-based-on-type-capture-clause.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 #![allow(unused_must_use)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 
diff --git a/tests/ui/panics/panic-handler-chain.rs b/tests/ui/panics/panic-handler-chain.rs
index eb23849f3ac..fea71ad9ec4 100644
--- a/tests/ui/panics/panic-handler-chain.rs
+++ b/tests/ui/panics/panic-handler-chain.rs
@@ -1,9 +1,8 @@
 //@ run-pass
 //@ needs-unwind
+//@ needs-threads
 #![allow(stable_features)]
 
-//@ ignore-emscripten no threads support
-
 #![feature(std_panic)]
 
 use std::sync::atomic::{AtomicUsize, Ordering};
diff --git a/tests/ui/panics/panic-task-name-none.rs b/tests/ui/panics/panic-task-name-none.rs
index 7eb974bde4c..8695771ff5e 100644
--- a/tests/ui/panics/panic-task-name-none.rs
+++ b/tests/ui/panics/panic-task-name-none.rs
@@ -1,7 +1,7 @@
 //@ run-fail
 //@ error-pattern:thread '<unnamed>' panicked
 //@ error-pattern:test
-//@ ignore-emscripten Needs threads
+//@ needs-threads
 
 use std::thread;
 
diff --git a/tests/ui/panics/panic-task-name-owned.rs b/tests/ui/panics/panic-task-name-owned.rs
index 9a680676dc0..42ae33b5d35 100644
--- a/tests/ui/panics/panic-task-name-owned.rs
+++ b/tests/ui/panics/panic-task-name-owned.rs
@@ -1,7 +1,7 @@
 //@ run-fail
 //@ error-pattern:thread 'owned name' panicked
 //@ error-pattern:test
-//@ ignore-emscripten Needs threads.
+//@ needs-threads
 
 use std::thread::Builder;
 
diff --git a/tests/ui/process-termination/process-termination-blocking-io.rs b/tests/ui/process-termination/process-termination-blocking-io.rs
index c21edff25cf..f725a958941 100644
--- a/tests/ui/process-termination/process-termination-blocking-io.rs
+++ b/tests/ui/process-termination/process-termination-blocking-io.rs
@@ -2,7 +2,7 @@
 // https://github.com/fortanix/rust-sgx/issues/109
 
 //@ run-pass
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::{net::TcpListener, sync::mpsc, thread};
 
diff --git a/tests/ui/process-termination/process-termination-simple.rs b/tests/ui/process-termination/process-termination-simple.rs
index 63eb2c74706..8f5f185b7f9 100644
--- a/tests/ui/process-termination/process-termination-simple.rs
+++ b/tests/ui/process-termination/process-termination-simple.rs
@@ -1,7 +1,7 @@
 // program should terminate when std::process::exit is called from any thread
 
 //@ run-pass
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::{process, thread};
 
diff --git a/tests/ui/structs-enums/ivec-tag.rs b/tests/ui/structs-enums/ivec-tag.rs
index 9185a0cbb6e..2a0b6dd1ed4 100644
--- a/tests/ui/structs-enums/ivec-tag.rs
+++ b/tests/ui/structs-enums/ivec-tag.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 #![allow(unused_must_use)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 use std::sync::mpsc::{channel, Sender};
diff --git a/tests/ui/test-attrs/test-filter-multiple.rs b/tests/ui/test-attrs/test-filter-multiple.rs
index 0347ce457ae..05fc022834a 100644
--- a/tests/ui/test-attrs/test-filter-multiple.rs
+++ b/tests/ui/test-attrs/test-filter-multiple.rs
@@ -3,7 +3,7 @@
 //@ run-flags: --test-threads=1 test1 test2
 //@ check-run-results
 //@ normalize-stdout-test "finished in \d+\.\d+s" -> "finished in $$TIME"
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 #[test]
 fn test1() {}
diff --git a/tests/ui/test-attrs/test-type.rs b/tests/ui/test-attrs/test-type.rs
index 8f75ff309e0..7db7e31d01d 100644
--- a/tests/ui/test-attrs/test-type.rs
+++ b/tests/ui/test-attrs/test-type.rs
@@ -2,7 +2,7 @@
 //@ run-flags: --test-threads=1
 //@ check-run-results
 //@ normalize-stdout-test "finished in \d+\.\d+s" -> "finished in $$TIME"
-//@ ignore-emscripten no threads support
+//@ needs-threads
 //@ run-pass
 
 #[test]
diff --git a/tests/ui/thread-local/tls.rs b/tests/ui/thread-local/tls.rs
index 17096319d23..fa6a722b291 100644
--- a/tests/ui/thread-local/tls.rs
+++ b/tests/ui/thread-local/tls.rs
@@ -1,5 +1,5 @@
 //@ run-pass
-//@ ignore-emscripten no threads support
+//@ needs-threads
 //@ compile-flags: -O
 //@ ignore-nto Doesn't work without emulated TLS enabled (in LLVM)
 
diff --git a/tests/ui/threads-sendsync/child-outlives-parent.rs b/tests/ui/threads-sendsync/child-outlives-parent.rs
index 2fb4a6f637a..213fd008cd3 100644
--- a/tests/ui/threads-sendsync/child-outlives-parent.rs
+++ b/tests/ui/threads-sendsync/child-outlives-parent.rs
@@ -2,7 +2,7 @@
 // Reported as issue #126, child leaks the string.
 
 //@ pretty-expanded FIXME #23616
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 
diff --git a/tests/ui/threads-sendsync/clone-with-exterior.rs b/tests/ui/threads-sendsync/clone-with-exterior.rs
index 58529e4a788..67790367e27 100644
--- a/tests/ui/threads-sendsync/clone-with-exterior.rs
+++ b/tests/ui/threads-sendsync/clone-with-exterior.rs
@@ -1,7 +1,7 @@
 //@ run-pass
 
 #![allow(unused_must_use)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 
diff --git a/tests/ui/threads-sendsync/comm.rs b/tests/ui/threads-sendsync/comm.rs
index 589859e60a6..0c37fda8a39 100644
--- a/tests/ui/threads-sendsync/comm.rs
+++ b/tests/ui/threads-sendsync/comm.rs
@@ -1,13 +1,13 @@
 //@ run-pass
 #![allow(unused_must_use)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 use std::sync::mpsc::{channel, Sender};
 
 pub fn main() {
     let (tx, rx) = channel();
-    let t = thread::spawn(move|| { child(&tx) });
+    let t = thread::spawn(move || { child(&tx) });
     let y = rx.recv().unwrap();
     println!("received");
     println!("{}", y);
diff --git a/tests/ui/threads-sendsync/eprint-on-tls-drop.rs b/tests/ui/threads-sendsync/eprint-on-tls-drop.rs
index 3ff9fb10f24..82abf21df3f 100644
--- a/tests/ui/threads-sendsync/eprint-on-tls-drop.rs
+++ b/tests/ui/threads-sendsync/eprint-on-tls-drop.rs
@@ -1,5 +1,5 @@
 //@ run-pass
-//@ ignore-emscripten no processes
+//@ needs-threads
 //@ ignore-sgx no processes
 
 use std::cell::RefCell;
diff --git a/tests/ui/threads-sendsync/issue-24313.rs b/tests/ui/threads-sendsync/issue-24313.rs
index 17e027520c1..1ea862f1e7d 100644
--- a/tests/ui/threads-sendsync/issue-24313.rs
+++ b/tests/ui/threads-sendsync/issue-24313.rs
@@ -1,5 +1,5 @@
 //@ run-pass
-//@ ignore-emscripten no threads
+//@ needs-threads
 //@ ignore-sgx no processes
 
 use std::thread;
diff --git a/tests/ui/threads-sendsync/issue-29488.rs b/tests/ui/threads-sendsync/issue-29488.rs
index c848e7b50bb..fbbd6b02a06 100644
--- a/tests/ui/threads-sendsync/issue-29488.rs
+++ b/tests/ui/threads-sendsync/issue-29488.rs
@@ -1,5 +1,5 @@
 //@ run-pass
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 
diff --git a/tests/ui/threads-sendsync/issue-43733-2.rs b/tests/ui/threads-sendsync/issue-43733-2.rs
index 5a9ee015cb9..372ebf2cff9 100644
--- a/tests/ui/threads-sendsync/issue-43733-2.rs
+++ b/tests/ui/threads-sendsync/issue-43733-2.rs
@@ -1,4 +1,4 @@
-//@ ignore-wasm32
+//@ needs-threads
 //@ dont-check-compiler-stderr
 #![feature(cfg_target_thread_local, thread_local_internals)]
 
diff --git a/tests/ui/threads-sendsync/issue-43733.rs b/tests/ui/threads-sendsync/issue-43733.rs
index 12207f4e6aa..c90f60887cf 100644
--- a/tests/ui/threads-sendsync/issue-43733.rs
+++ b/tests/ui/threads-sendsync/issue-43733.rs
@@ -1,4 +1,4 @@
-//@ ignore-wasm32
+//@ needs-threads
 #![feature(thread_local)]
 #![feature(cfg_target_thread_local, thread_local_internals)]
 
diff --git a/tests/ui/threads-sendsync/issue-4446.rs b/tests/ui/threads-sendsync/issue-4446.rs
index b5e3a20ccde..aa2de51974b 100644
--- a/tests/ui/threads-sendsync/issue-4446.rs
+++ b/tests/ui/threads-sendsync/issue-4446.rs
@@ -1,5 +1,5 @@
 //@ run-pass
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::sync::mpsc::channel;
 use std::thread;
diff --git a/tests/ui/threads-sendsync/issue-4448.rs b/tests/ui/threads-sendsync/issue-4448.rs
index 0f3bf65c441..b8324a8c43f 100644
--- a/tests/ui/threads-sendsync/issue-4448.rs
+++ b/tests/ui/threads-sendsync/issue-4448.rs
@@ -1,5 +1,5 @@
 //@ run-pass
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::sync::mpsc::channel;
 use std::thread;
diff --git a/tests/ui/threads-sendsync/issue-8827.rs b/tests/ui/threads-sendsync/issue-8827.rs
index b7deef0f34d..fa07a4ebc7d 100644
--- a/tests/ui/threads-sendsync/issue-8827.rs
+++ b/tests/ui/threads-sendsync/issue-8827.rs
@@ -1,5 +1,5 @@
 //@ run-pass
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 use std::sync::mpsc::{channel, Receiver};
diff --git a/tests/ui/threads-sendsync/issue-9396.rs b/tests/ui/threads-sendsync/issue-9396.rs
index 6228f4ba706..6b5907e5c1d 100644
--- a/tests/ui/threads-sendsync/issue-9396.rs
+++ b/tests/ui/threads-sendsync/issue-9396.rs
@@ -1,7 +1,7 @@
 //@ run-pass
 #![allow(unused_must_use)]
 #![allow(deprecated)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::sync::mpsc::{TryRecvError, channel};
 use std::thread;
diff --git a/tests/ui/threads-sendsync/mpsc_stress.rs b/tests/ui/threads-sendsync/mpsc_stress.rs
index 68c40151281..f5354c60bfc 100644
--- a/tests/ui/threads-sendsync/mpsc_stress.rs
+++ b/tests/ui/threads-sendsync/mpsc_stress.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 //@ compile-flags:--test
-//@ ignore-emscripten
+//@ needs-threads
 
 use std::sync::mpsc::channel;
 use std::sync::mpsc::TryRecvError;
diff --git a/tests/ui/threads-sendsync/send-resource.rs b/tests/ui/threads-sendsync/send-resource.rs
index 32910c5f7d1..3e1532b3132 100644
--- a/tests/ui/threads-sendsync/send-resource.rs
+++ b/tests/ui/threads-sendsync/send-resource.rs
@@ -4,7 +4,7 @@
 #![allow(non_camel_case_types)]
 
 //@ pretty-expanded FIXME #23616
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 use std::sync::mpsc::channel;
diff --git a/tests/ui/threads-sendsync/sendfn-spawn-with-fn-arg.rs b/tests/ui/threads-sendsync/sendfn-spawn-with-fn-arg.rs
index 5306d69a7d2..63cf3ff4049 100644
--- a/tests/ui/threads-sendsync/sendfn-spawn-with-fn-arg.rs
+++ b/tests/ui/threads-sendsync/sendfn-spawn-with-fn-arg.rs
@@ -1,5 +1,5 @@
 //@ run-pass
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 
diff --git a/tests/ui/threads-sendsync/spawn-fn.rs b/tests/ui/threads-sendsync/spawn-fn.rs
index 863c22f70d6..e4d83b53f3c 100644
--- a/tests/ui/threads-sendsync/spawn-fn.rs
+++ b/tests/ui/threads-sendsync/spawn-fn.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 #![allow(unused_must_use)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 
diff --git a/tests/ui/threads-sendsync/spawn-types.rs b/tests/ui/threads-sendsync/spawn-types.rs
index 9c1b6550d9b..2a7a9e2f497 100644
--- a/tests/ui/threads-sendsync/spawn-types.rs
+++ b/tests/ui/threads-sendsync/spawn-types.rs
@@ -1,7 +1,7 @@
 //@ run-pass
 #![allow(non_camel_case_types)]
 
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 /*
   Make sure we can spawn tasks that take different types of
diff --git a/tests/ui/threads-sendsync/spawn.rs b/tests/ui/threads-sendsync/spawn.rs
index 2c06fc2837f..c7b344b9f75 100644
--- a/tests/ui/threads-sendsync/spawn.rs
+++ b/tests/ui/threads-sendsync/spawn.rs
@@ -1,5 +1,5 @@
 //@ run-pass
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 
diff --git a/tests/ui/threads-sendsync/spawn2.rs b/tests/ui/threads-sendsync/spawn2.rs
index cfe907ea6d9..8278fec1885 100644
--- a/tests/ui/threads-sendsync/spawn2.rs
+++ b/tests/ui/threads-sendsync/spawn2.rs
@@ -1,5 +1,5 @@
 //@ run-pass
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 
diff --git a/tests/ui/threads-sendsync/spawning-with-debug.rs b/tests/ui/threads-sendsync/spawning-with-debug.rs
index 58f1743527c..90a81c1e53b 100644
--- a/tests/ui/threads-sendsync/spawning-with-debug.rs
+++ b/tests/ui/threads-sendsync/spawning-with-debug.rs
@@ -3,7 +3,7 @@
 #![allow(unused_mut)]
 //@ ignore-windows
 //@ exec-env:RUST_LOG=debug
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 // regression test for issue #10405, make sure we don't call println! too soon.
 
diff --git a/tests/ui/threads-sendsync/task-comm-0.rs b/tests/ui/threads-sendsync/task-comm-0.rs
index 06ce739b8e5..50f2b591894 100644
--- a/tests/ui/threads-sendsync/task-comm-0.rs
+++ b/tests/ui/threads-sendsync/task-comm-0.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 #![allow(unused_must_use)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 use std::sync::mpsc::{channel, Sender};
diff --git a/tests/ui/threads-sendsync/task-comm-1.rs b/tests/ui/threads-sendsync/task-comm-1.rs
index 77ca940e947..41592bd916b 100644
--- a/tests/ui/threads-sendsync/task-comm-1.rs
+++ b/tests/ui/threads-sendsync/task-comm-1.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 #![allow(unused_must_use)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 
diff --git a/tests/ui/threads-sendsync/task-comm-10.rs b/tests/ui/threads-sendsync/task-comm-10.rs
index 6f043b64a09..844652c0dde 100644
--- a/tests/ui/threads-sendsync/task-comm-10.rs
+++ b/tests/ui/threads-sendsync/task-comm-10.rs
@@ -1,7 +1,7 @@
 //@ run-pass
 #![allow(unused_must_use)]
 #![allow(unused_mut)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 use std::sync::mpsc::{channel, Sender};
diff --git a/tests/ui/threads-sendsync/task-comm-11.rs b/tests/ui/threads-sendsync/task-comm-11.rs
index 51f13434435..199082fda96 100644
--- a/tests/ui/threads-sendsync/task-comm-11.rs
+++ b/tests/ui/threads-sendsync/task-comm-11.rs
@@ -1,7 +1,7 @@
 //@ run-pass
 #![allow(unused_must_use)]
 //@ pretty-expanded FIXME #23616
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::sync::mpsc::{channel, Sender};
 use std::thread;
diff --git a/tests/ui/threads-sendsync/task-comm-12.rs b/tests/ui/threads-sendsync/task-comm-12.rs
index cb1fb774f10..7be7ec4c988 100644
--- a/tests/ui/threads-sendsync/task-comm-12.rs
+++ b/tests/ui/threads-sendsync/task-comm-12.rs
@@ -1,7 +1,7 @@
 //@ run-pass
 #![allow(unused_must_use)]
 #![allow(unused_mut)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 
diff --git a/tests/ui/threads-sendsync/task-comm-13.rs b/tests/ui/threads-sendsync/task-comm-13.rs
index 6b5384e3f08..414e6e0db76 100644
--- a/tests/ui/threads-sendsync/task-comm-13.rs
+++ b/tests/ui/threads-sendsync/task-comm-13.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 #![allow(unused_variables)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::sync::mpsc::{channel, Sender};
 use std::thread;
diff --git a/tests/ui/threads-sendsync/task-comm-14.rs b/tests/ui/threads-sendsync/task-comm-14.rs
index 65cc750a7c3..54deb221294 100644
--- a/tests/ui/threads-sendsync/task-comm-14.rs
+++ b/tests/ui/threads-sendsync/task-comm-14.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 #![allow(unused_parens)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::sync::mpsc::{channel, Sender};
 use std::thread;
diff --git a/tests/ui/threads-sendsync/task-comm-15.rs b/tests/ui/threads-sendsync/task-comm-15.rs
index 844a18b6158..f487bf3cc84 100644
--- a/tests/ui/threads-sendsync/task-comm-15.rs
+++ b/tests/ui/threads-sendsync/task-comm-15.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 #![allow(unused_must_use)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 //@ pretty-expanded FIXME #23616
 
 use std::sync::mpsc::{channel, Sender};
diff --git a/tests/ui/threads-sendsync/task-comm-17.rs b/tests/ui/threads-sendsync/task-comm-17.rs
index 14ef4dd3ede..687322d4dc9 100644
--- a/tests/ui/threads-sendsync/task-comm-17.rs
+++ b/tests/ui/threads-sendsync/task-comm-17.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 #![allow(unused_must_use)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 //@ pretty-expanded FIXME #23616
 
 // Issue #922
diff --git a/tests/ui/threads-sendsync/task-comm-3.rs b/tests/ui/threads-sendsync/task-comm-3.rs
index 1f2a6406d79..26f3eaf9dc6 100644
--- a/tests/ui/threads-sendsync/task-comm-3.rs
+++ b/tests/ui/threads-sendsync/task-comm-3.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 #![allow(unused_must_use)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 use std::sync::mpsc::{channel, Sender};
diff --git a/tests/ui/threads-sendsync/task-comm-7.rs b/tests/ui/threads-sendsync/task-comm-7.rs
index f6e77986e16..d9b322daa66 100644
--- a/tests/ui/threads-sendsync/task-comm-7.rs
+++ b/tests/ui/threads-sendsync/task-comm-7.rs
@@ -1,7 +1,7 @@
 //@ run-pass
 #![allow(unused_must_use)]
 #![allow(unused_assignments)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::sync::mpsc::{channel, Sender};
 use std::thread;
diff --git a/tests/ui/threads-sendsync/task-comm-9.rs b/tests/ui/threads-sendsync/task-comm-9.rs
index f8fe680e5e0..3e617e4a40c 100644
--- a/tests/ui/threads-sendsync/task-comm-9.rs
+++ b/tests/ui/threads-sendsync/task-comm-9.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 #![allow(unused_must_use)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 use std::sync::mpsc::{channel, Sender};
diff --git a/tests/ui/threads-sendsync/task-life-0.rs b/tests/ui/threads-sendsync/task-life-0.rs
index a4652197afc..d3eca5d371f 100644
--- a/tests/ui/threads-sendsync/task-life-0.rs
+++ b/tests/ui/threads-sendsync/task-life-0.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 #![allow(unused_must_use)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 //@ pretty-expanded FIXME #23616
 
 use std::thread;
diff --git a/tests/ui/threads-sendsync/task-spawn-barefn.rs b/tests/ui/threads-sendsync/task-spawn-barefn.rs
index 2c957878c95..a97e92206e2 100644
--- a/tests/ui/threads-sendsync/task-spawn-barefn.rs
+++ b/tests/ui/threads-sendsync/task-spawn-barefn.rs
@@ -1,6 +1,6 @@
 //@ run-fail
 //@ error-pattern:Ensure that the child thread runs by panicking
-//@ ignore-emscripten Needs threads.
+//@ needs-threads
 
 use std::thread;
 
diff --git a/tests/ui/threads-sendsync/task-spawn-move-and-copy.rs b/tests/ui/threads-sendsync/task-spawn-move-and-copy.rs
index 442955421d8..ea1c6a9b108 100644
--- a/tests/ui/threads-sendsync/task-spawn-move-and-copy.rs
+++ b/tests/ui/threads-sendsync/task-spawn-move-and-copy.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 #![allow(unused_must_use)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 use std::sync::mpsc::channel;
diff --git a/tests/ui/threads-sendsync/task-stderr.rs b/tests/ui/threads-sendsync/task-stderr.rs
index 0f215a2b763..cad10c7a792 100644
--- a/tests/ui/threads-sendsync/task-stderr.rs
+++ b/tests/ui/threads-sendsync/task-stderr.rs
@@ -1,5 +1,5 @@
 //@ run-pass
-//@ ignore-emscripten no threads support
+//@ needs-threads
 //@ needs-unwind
 
 #![feature(internal_output_capture)]
diff --git a/tests/ui/threads-sendsync/tcp-stress.rs b/tests/ui/threads-sendsync/tcp-stress.rs
index 488cab40140..429a4657314 100644
--- a/tests/ui/threads-sendsync/tcp-stress.rs
+++ b/tests/ui/threads-sendsync/tcp-stress.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 //@ ignore-android needs extra network permissions
-//@ ignore-emscripten no threads or sockets support
+//@ needs-threads
 //@ ignore-netbsd system ulimit (Too many open files)
 //@ ignore-openbsd system ulimit (Too many open files)
 
diff --git a/tests/ui/threads-sendsync/test-tasks-invalid-value.rs b/tests/ui/threads-sendsync/test-tasks-invalid-value.rs
index 4b38b9ce2c9..127086743ca 100644
--- a/tests/ui/threads-sendsync/test-tasks-invalid-value.rs
+++ b/tests/ui/threads-sendsync/test-tasks-invalid-value.rs
@@ -5,7 +5,7 @@
 //@ error-pattern:should be a positive integer
 //@ compile-flags: --test
 //@ exec-env:RUST_TEST_THREADS=foo
-//@ ignore-emscripten
+//@ needs-threads
 
 #[test]
 fn do_nothing() {}
diff --git a/tests/ui/threads-sendsync/threads.rs b/tests/ui/threads-sendsync/threads.rs
index 7b7e52abab4..f3ed7890364 100644
--- a/tests/ui/threads-sendsync/threads.rs
+++ b/tests/ui/threads-sendsync/threads.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 #![allow(unused_must_use)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 
diff --git a/tests/ui/threads-sendsync/tls-dtors-are-run-in-a-static-binary.rs b/tests/ui/threads-sendsync/tls-dtors-are-run-in-a-static-binary.rs
index 66fd6169db0..84176659412 100644
--- a/tests/ui/threads-sendsync/tls-dtors-are-run-in-a-static-binary.rs
+++ b/tests/ui/threads-sendsync/tls-dtors-are-run-in-a-static-binary.rs
@@ -1,6 +1,6 @@
 //@ run-pass
 //@ no-prefer-dynamic
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 static mut HIT: bool = false;
 
diff --git a/tests/ui/threads-sendsync/tls-init-on-init.rs b/tests/ui/threads-sendsync/tls-init-on-init.rs
index ba5e4698e63..fd764669e7f 100644
--- a/tests/ui/threads-sendsync/tls-init-on-init.rs
+++ b/tests/ui/threads-sendsync/tls-init-on-init.rs
@@ -1,7 +1,7 @@
 //@ run-pass
 #![allow(stable_features)]
 
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 #![feature(thread_local_try_with)]
 
diff --git a/tests/ui/threads-sendsync/tls-try-with.rs b/tests/ui/threads-sendsync/tls-try-with.rs
index d9af1caf741..72cee219a0a 100644
--- a/tests/ui/threads-sendsync/tls-try-with.rs
+++ b/tests/ui/threads-sendsync/tls-try-with.rs
@@ -1,7 +1,7 @@
 //@ run-pass
 #![allow(stable_features)]
 
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 #![feature(thread_local_try_with)]
 
diff --git a/tests/ui/threads-sendsync/unwind-resource.rs b/tests/ui/threads-sendsync/unwind-resource.rs
index ea9e0c7514c..3b1ab57b46e 100644
--- a/tests/ui/threads-sendsync/unwind-resource.rs
+++ b/tests/ui/threads-sendsync/unwind-resource.rs
@@ -2,7 +2,7 @@
 //@ needs-unwind
 
 #![allow(non_camel_case_types)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::sync::mpsc::{channel, Sender};
 use std::thread;
diff --git a/tests/ui/threads-sendsync/yield.rs b/tests/ui/threads-sendsync/yield.rs
index 4d89b10af95..99d14bd92ea 100644
--- a/tests/ui/threads-sendsync/yield.rs
+++ b/tests/ui/threads-sendsync/yield.rs
@@ -2,7 +2,7 @@
 
 #![allow(unused_must_use)]
 #![allow(unused_mut)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 
diff --git a/tests/ui/threads-sendsync/yield1.rs b/tests/ui/threads-sendsync/yield1.rs
index b003a70f47e..c965d2fc303 100644
--- a/tests/ui/threads-sendsync/yield1.rs
+++ b/tests/ui/threads-sendsync/yield1.rs
@@ -2,7 +2,7 @@
 
 #![allow(unused_must_use)]
 #![allow(unused_mut)]
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::thread;
 
diff --git a/tests/ui/traits/bound/in-arc.rs b/tests/ui/traits/bound/in-arc.rs
index 40a6115e838..2616ad84ff8 100644
--- a/tests/ui/traits/bound/in-arc.rs
+++ b/tests/ui/traits/bound/in-arc.rs
@@ -3,7 +3,7 @@
 // Tests that a heterogeneous list of existential `dyn` types can be put inside an Arc
 // and shared between threads as long as all types fulfill Send.
 
-//@ ignore-emscripten no threads support
+//@ needs-threads
 
 use std::sync::Arc;
 use std::sync::mpsc::channel;