Preserve deprecation attribute even if 'since' version is missing

Author: dtolnay

compiler/rustc_attr/src/builtin.rs

@@ -876,10 +876,10 @@ pub fn find_deprecation(
                 sess.emit_err(session_diagnostics::InvalidSince { span: attr.span });
                 Some(DeprecatedSince::Err)
             }
-        } else if is_rustc {
-            sess.emit_err(session_diagnostics::MissingSince { span: attr.span });
-            continue;
         } else {
+            if is_rustc {
+                sess.emit_err(session_diagnostics::MissingSince { span: attr.span });
+            }
             None
         };
 

tests/ui/stability-attribute/stability-attribute-sanity-4.rs

@@ -19,6 +19,7 @@ mod bogus_attribute_types_2 {
 
     #[stable(feature = "a", since = "3.3.3")]
     #[deprecated] //~ ERROR missing 'since'
+    //~^ ERROR missing 'note'
     fn f5() { }
 
     #[stable(feature = "a", since = "3.3.3")]

tests/ui/stability-attribute/stability-attribute-sanity-4.stderr

@@ -28,12 +28,19 @@ error[E0542]: missing 'since'
 LL |     #[deprecated]
    |     ^^^^^^^^^^^^^
 
+error[E0543]: missing 'note'
+  --> $DIR/stability-attribute-sanity-4.rs:21:5
+   |
+LL |     #[deprecated]
+   |     ^^^^^^^^^^^^^
+
 error[E0542]: missing 'since'
-  --> $DIR/stability-attribute-sanity-4.rs:25:5
+  --> $DIR/stability-attribute-sanity-4.rs:26:5
    |
 LL |     #[deprecated = "a"]
    |     ^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 6 previous errors
+error: aborting due to 7 previous errors
 
-For more information about this error, try `rustc --explain E0542`.
+Some errors have detailed explanations: E0542, E0543.
+For more information about an error, try `rustc --explain E0542`.