Rollup merge of rust-lang#51298 - Dylan-DPC:stabilise/termination-test, r=nikomatsakis

Stabilize unit tests with non-`()` return type

References rust-lang#48854

Author: Mark-Simulacrum

src/libsyntax/feature_gate.rs

@@ -398,9 +398,6 @@ declare_features! (
     // `foo.rs` as an alternative to `foo/mod.rs`
     (active, non_modrs_mods, "1.24.0", Some(44660), Some(Edition::Edition2018)),
 
-    // Termination trait in tests (RFC 1937)
-    (active, termination_trait_test, "1.24.0", Some(48854), Some(Edition::Edition2018)),
-
     // `extern` in paths
     (active, extern_in_paths, "1.23.0", Some(44660), None),
 
@@ -616,6 +613,8 @@ declare_features! (
     (accepted, fn_must_use, "1.27.0", Some(43302), None),
     // Allows use of the :lifetime macro fragment specifier
     (accepted, macro_lifetime_matcher, "1.27.0", Some(34303), None),
+    // Termination trait in tests (RFC 1937)
+    (accepted, termination_trait_test, "1.27.0", Some(48854), None),
 );
 
 // If you change this, please modify src/doc/unstable-book as well. You must

src/libsyntax/test.rs

@@ -335,7 +335,7 @@ enum BadTestSignature {
 fn is_test_fn(cx: &TestCtxt, i: &ast::Item) -> bool {
     let has_test_attr = attr::contains_name(&i.attrs, "test");
 
-    fn has_test_signature(cx: &TestCtxt, i: &ast::Item) -> HasTestSignature {
+    fn has_test_signature(_cx: &TestCtxt, i: &ast::Item) -> HasTestSignature {
         let has_should_panic_attr = attr::contains_name(&i.attrs, "should_panic");
         match i.node {
             ast::ItemKind::Fn(ref decl, _, _, _, ref generics, _) => {
@@ -351,15 +351,14 @@ fn is_test_fn(cx: &TestCtxt, i: &ast::Item) -> bool {
                     return No(BadTestSignature::NoArgumentsAllowed);
                 }
 
-                match (has_output, cx.features.termination_trait_test, has_should_panic_attr) {
-                    (true, true, true) => No(BadTestSignature::ShouldPanicOnlyWithNoArgs),
-                    (true, true, false) => if generics.is_parameterized() {
+                match (has_output, has_should_panic_attr) {
+                    (true, true) => No(BadTestSignature::ShouldPanicOnlyWithNoArgs),
+                    (true, false) => if generics.is_parameterized() {
                         No(BadTestSignature::WrongTypeSignature)
                     } else {
                         Yes
                     },
-                    (true, false, _) => No(BadTestSignature::WrongTypeSignature),
-                    (false, _, _) => Yes
+                    (false, _) => Yes
                 }
             }
             _ => No(BadTestSignature::NotEvenAFunction),
@@ -395,31 +394,12 @@ fn is_test_fn(cx: &TestCtxt, i: &ast::Item) -> bool {
 fn is_bench_fn(cx: &TestCtxt, i: &ast::Item) -> bool {
     let has_bench_attr = attr::contains_name(&i.attrs, "bench");
 
-    fn has_bench_signature(cx: &TestCtxt, i: &ast::Item) -> bool {
+    fn has_bench_signature(_cx: &TestCtxt, i: &ast::Item) -> bool {
         match i.node {
-            ast::ItemKind::Fn(ref decl, _, _, _, ref generics, _) => {
-                let input_cnt = decl.inputs.len();
-
-                // If the termination trait is active, the compiler will check that the output
-                // type implements the `Termination` trait as `libtest` enforces that.
-                let output_matches = if cx.features.termination_trait_test {
-                    true
-                } else {
-                    let no_output = match decl.output {
-                        ast::FunctionRetTy::Default(..) => true,
-                        ast::FunctionRetTy::Ty(ref t) if t.node == ast::TyKind::Tup(vec![]) => true,
-                        _ => false
-                    };
-                    let tparm_cnt = generics.params.iter()
-                        .filter(|param| param.is_type_param())
-                        .count();
-
-                    no_output && tparm_cnt == 0
-                };
-
+            ast::ItemKind::Fn(ref decl, _, _, _, _, _) => {
                 // NB: inadequate check, but we're running
                 // well before resolve, can't get too deep.
-                input_cnt == 1 && output_matches
+                decl.inputs.len() == 1
             }
             _ => false
         }
@@ -430,13 +410,8 @@ fn is_bench_fn(cx: &TestCtxt, i: &ast::Item) -> bool {
     if has_bench_attr && !has_bench_signature {
         let diag = cx.span_diagnostic;
 
-        if cx.features.termination_trait_test {
-            diag.span_err(i.span, "functions used as benches must have signature \
+        diag.span_err(i.span, "functions used as benches must have signature \
                                    `fn(&mut Bencher) -> impl Termination`");
-        } else {
-            diag.span_err(i.span, "functions used as benches must have signature \
-                                   `fn(&mut Bencher) -> ()`");
-        }
     }
 
     has_bench_attr && has_bench_signature

src/test/compile-fail/feature-gate-termination_trait_test.rs

@@ -10,7 +10,6 @@
 
 // compile-flags: --test
 
-#![feature(termination_trait_test)]
 #![feature(test)]
 
 extern crate test;

src/test/ui/rfc-1937-termination-trait/termination-trait-in-test-should-panic.rs

@@ -1,5 +1,5 @@
 error: functions using `#[should_panic]` must return `()`
-  --> $DIR/termination-trait-in-test-should-panic.rs:22:1
+  --> $DIR/termination-trait-in-test-should-panic.rs:21:1
    |
 LL | / fn not_a_num() -> Result<(), ParseIntError> {
 LL | |     //~^ ERROR functions using `#[should_panic]` must return `()`

src/test/ui/rfc-1937-termination-trait/termination-trait-in-test-should-panic.stderr

@@ -11,7 +11,6 @@
 // compile-flags: --test
 // run-pass
 
-#![feature(termination_trait_test)]
 #![feature(test)]
 
 extern crate test;

src/test/ui/rfc-1937-termination-trait/termination-trait-in-test.rs

@@ -10,8 +10,6 @@
 
 // compile-flags: --test
 
-#![feature(termination_trait_test)]
-
 use std::num::ParseIntError;
 
 #[test]

src/test/ui/rfc-1937-termination-trait/termination-trait-test-wrong-type.rs

@@ -1,5 +1,5 @@
 error[E0277]: `main` has invalid return type `std::result::Result<f32, std::num::ParseIntError>`
-  --> $DIR/termination-trait-test-wrong-type.rs:18:1
+  --> $DIR/termination-trait-test-wrong-type.rs:16:1
    |
 LL | / fn can_parse_zero_as_f32() -> Result<f32, ParseIntError> { //~ ERROR
 LL | |     "0".parse()