Make sure feature gate errors are recoverable (take 2)

Author: petrochenkov

src/librustc/ty/mod.rs

@@ -2839,16 +2839,14 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
                 && trait1_is_empty
                 && trait2_is_empty
-        } else if self.features().marker_trait_attr {
+        } else {
             let is_marker_impl = |def_id: DefId| -> bool {
                 let trait_ref = self.impl_trait_ref(def_id);
                 trait_ref.map_or(false, |tr| self.trait_def(tr.def_id).is_marker)
             };
             self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
                 && is_marker_impl(def_id1)
                 && is_marker_impl(def_id2)
-        } else {
-            false
         };
 
         if is_legit {

src/librustc_driver/driver.rs

@@ -1098,23 +1098,20 @@ where
         ast_validation::check_crate(sess, &krate)
     });
 
-    time(sess, "name resolution", || -> CompileResult {
+    time(sess, "name resolution", || {
         resolver.resolve_crate(&krate);
-        Ok(())
-    })?;
+    });
 
     // Needs to go *after* expansion to be able to check the results of macro expansion.
     time(sess, "complete gated feature checking", || {
-        sess.track_errors(|| {
-            syntax::feature_gate::check_crate(
-                &krate,
-                &sess.parse_sess,
-                &sess.features_untracked(),
-                &attributes,
-                sess.opts.unstable_features,
-            );
-        })
-    })?;
+        syntax::feature_gate::check_crate(
+            &krate,
+            &sess.parse_sess,
+            &sess.features_untracked(),
+            &attributes,
+            sess.opts.unstable_features,
+        );
+    });
 
     // Lower ast -> hir.
     // First, we need to collect the dep_graph.

src/test/ui/conditional-compilation/cfg-attr-crate-2.rs

@@ -1,8 +1,8 @@
-//
-// compile-flags: --cfg broken
-
 // https://github.com/rust-lang/rust/issues/21833#issuecomment-72353044
 
+// compile-flags: --cfg broken
+
+#![crate_type = "lib"]
 #![cfg_attr(broken, no_core)] //~ ERROR no_core is experimental
 
-fn main() { }
+pub struct S {}

src/test/ui/conditional-compilation/cfg-attr-multi-invalid-1.rs

@@ -1,7 +1,7 @@
-//
 // compile-flags: --cfg broken
 
 #![feature(cfg_attr_multi)]
+#![crate_type = "lib"]
 #![cfg_attr(broken, no_core, no_std)] //~ ERROR no_core is experimental
 
-fn main() { }
+pub struct S {}

src/test/ui/conditional-compilation/cfg-attr-multi-invalid-2.rs

@@ -1,7 +1,7 @@
-//
 // compile-flags: --cfg broken
 
 #![feature(cfg_attr_multi)]
+#![crate_type = "lib"]
 #![cfg_attr(broken, no_std, no_core)] //~ ERROR no_core is experimental
 
-fn main() { }
+pub struct S {}

src/test/ui/feature-gates/feature-gate-alloc-error-handler.rs

@@ -9,3 +9,6 @@ use core::alloc::Layout;
 fn oom(info: Layout) -> ! {
     loop {}
 }
+
+#[panic_handler]
+fn panic(_: &core::panic::PanicInfo) -> ! { loop {} }

src/test/ui/feature-gates/feature-gate-allow_fail.rs

@@ -5,3 +5,4 @@ fn ok_to_fail() {
     assert!(false);
 }
 
+fn main() {}

src/test/ui/feature-gates/feature-gate-async-await-2015-edition.rs

@@ -6,5 +6,5 @@ async fn foo() {} //~ ERROR async fn is unstable
 
 fn main() {
     let _ = async {}; //~ ERROR cannot find struct, variant or union type `async`
-    let _ = async || {}; //~ ERROR cannot find value `async` in this scope
+    let _ = async || { true }; //~ ERROR cannot find value `async` in this scope
 }

src/test/ui/feature-gates/feature-gate-async-await-2015-edition.stderr

@@ -7,7 +7,7 @@ LL |     let _ = async {}; //~ ERROR cannot find struct, variant or union type `
 error[E0425]: cannot find value `async` in this scope
   --> $DIR/feature-gate-async-await-2015-edition.rs:9:13
    |
-LL |     let _ = async || {}; //~ ERROR cannot find value `async` in this scope
+LL |     let _ = async || { true }; //~ ERROR cannot find value `async` in this scope
    |             ^^^^^ not found in this scope
 
 error[E0658]: async fn is unstable (see issue #50547)

src/test/ui/feature-gates/feature-gate-const_fn.rs

@@ -9,14 +9,16 @@ trait Foo {
                                 //~| ERROR trait fns cannot be declared const
 }
 
-impl Foo {
-    const fn baz() -> u32 { 0 } // ok
-}
-
 impl Foo for u32 {
     const fn foo() -> u32 { 0 } //~ ERROR trait fns cannot be declared const
 }
 
+trait Bar {}
+
+impl dyn Bar {
+    const fn baz() -> u32 { 0 } // ok
+}
+
 static FOO: usize = foo();
 const BAR: usize = foo();