Correctly analyze sealed status of traits with multiple supertraits. (#374)

src/adapter/tests.rs

@@ -233,6 +233,10 @@ fn rustdoc_sealed_traits() {
             name: "TransitivelyTraitSealed".into(),
             sealed: true,
         },
+        Output {
+            name: "SealedTraitWithStdSupertrait".into(),
+            sealed: true,
+        },
         Output {
             name: "Unsealed".into(),
             sealed: false,

src/sealed_trait.rs

@@ -56,7 +56,7 @@ fn has_sealed_supertrait<'a>(indexed_crate: &IndexedCrate<'a>, inner: &'a Trait)
                         // TODO: Once we have the ability to do cross-crate analysis, consider
                         //       whether this external trait is sealed. That can have
                         //       some interesting SemVer implications as well.
-                        return false;
+                        continue;
                     }
                 }
             }

test_crates/sealed_traits/src/lib.rs

@@ -12,6 +12,9 @@ pub trait DirectlyTraitSealed: private::Sealed {}
 /// This trait is sealed since nobody can implement its supertrait.
 pub trait TransitivelyTraitSealed: DirectlyTraitSealed {}
 
+/// This trait is sealed, and happens to have more than one supertrait.
+pub trait SealedTraitWithStdSupertrait: AsRef<()> + private::Sealed {}
+
 pub trait Unsealed {}
 
 /// This trait is sealed because its argument type is pub-in-priv,