Handle more cases in cfg_accessible

compiler/rustc_resolve/src/macros.rs

@@ -443,11 +443,20 @@ fn cfg_accessible(
                 PathResult::NonModule(partial_res) if partial_res.unresolved_segments() == 0 => {
                     return Ok(true);
                 }
+                PathResult::NonModule(..) => {
+                    self.session
+                        .struct_span_err(span, "not sure whether the path is accessible or not")
+                        .note("the type may have associated items, but we are currently not checking them")
+                        .emit();
+
+                    // If we get a partially resolved NonModule in one namespace, we should get the
+                    // same result in any other namespaces, so we can return early.
+                    return Ok(false);
+                }
                 PathResult::Indeterminate => indeterminate = true,
-                // FIXME: `resolve_path` is not ready to report partially resolved paths
-                // correctly, so we just report an error if the path was reported as unresolved.
-                // This needs to be fixed for `cfg_accessible` to be useful.
-                PathResult::NonModule(..) | PathResult::Failed { .. } => {}
+                // We can only be sure that a path doesn't exist after having tested all the
+                // posibilities, only at that time we can return false.
+                PathResult::Failed { .. } => {}
                 PathResult::Module(_) => panic!("unexpected path resolution"),
             }
         }
@@ -456,10 +465,6 @@ fn cfg_accessible(
             return Err(Indeterminate);
         }
 
-        self.session
-            .struct_span_err(span, "not sure whether the path is accessible or not")
-            .span_note(span, "`cfg_accessible` is not fully implemented")
-            .emit();
         Ok(false)
     }
 

src/test/ui/conditional-compilation/cfg_accessible.rs

@@ -5,20 +5,35 @@ mod m {
     struct ExistingPrivate;
 }
 
+trait Trait {
+    type Assoc;
+}
+
+enum Enum {
+    Existing,
+}
+
+#[cfg_accessible(Enum)]
+struct ExistingResolved;
+
+#[cfg_accessible(Enum::Existing)]
+struct ExistingResolvedVariant;
+
 #[cfg_accessible(m::ExistingPublic)]
 struct ExistingPublic;
 
-// FIXME: Not implemented yet.
-#[cfg_accessible(m::ExistingPrivate)] //~ ERROR not sure whether the path is accessible or not
+#[cfg_accessible(m::ExistingPrivate)]
 struct ExistingPrivate;
 
-// FIXME: Not implemented yet.
-#[cfg_accessible(m::NonExistent)] //~ ERROR not sure whether the path is accessible or not
-struct ExistingPrivate;
+#[cfg_accessible(m::NonExistent)]
+struct NonExistingPrivate;
 
 #[cfg_accessible(n::AccessibleExpanded)] // OK, `cfg_accessible` can wait and retry.
 struct AccessibleExpanded;
 
+#[cfg_accessible(Trait::Assoc)]
+struct AccessibleTraitAssoc;
+
 macro_rules! generate_accessible_expanded {
     () => {
         mod n {
@@ -29,15 +44,12 @@ mod n {
 
 generate_accessible_expanded!();
 
-struct S {
-    field: u8,
-}
-
-// FIXME: Not implemented yet.
-#[cfg_accessible(S::field)] //~ ERROR not sure whether the path is accessible or not
-struct Field;
-
 fn main() {
     ExistingPublic;
     AccessibleExpanded;
+    AccessibleTraitAssoc;
+
+    ExistingPrivate; //~ ERROR cannot find
+    NonExistingPrivate; //~ ERROR cannot find
+    NonExistingTraitAlias; //~ ERROR cannot find
 }

src/test/ui/conditional-compilation/cfg_accessible.stderr

-error: not sure whether the path is accessible or not
-  --> $DIR/cfg_accessible.rs:12:18
+error[E0425]: cannot find value `ExistingPrivate` in this scope
+  --> $DIR/cfg_accessible.rs:52:5
    |
-LL | #[cfg_accessible(m::ExistingPrivate)]
-   |                  ^^^^^^^^^^^^^^^^^^
+LL |     ExistingPrivate;
+   |     ^^^^^^^^^^^^^^^ not found in this scope
    |
-note: `cfg_accessible` is not fully implemented
-  --> $DIR/cfg_accessible.rs:12:18
+note: unit struct `m::ExistingPrivate` exists but is inaccessible
+  --> $DIR/cfg_accessible.rs:5:5
    |
-LL | #[cfg_accessible(m::ExistingPrivate)]
-   |                  ^^^^^^^^^^^^^^^^^^
+LL |     struct ExistingPrivate;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^ not accessible
 
-error: not sure whether the path is accessible or not
-  --> $DIR/cfg_accessible.rs:16:18
+error[E0425]: cannot find value `NonExistingPrivate` in this scope
+  --> $DIR/cfg_accessible.rs:53:5
    |
-LL | #[cfg_accessible(m::NonExistent)]
-   |                  ^^^^^^^^^^^^^^
-   |
-note: `cfg_accessible` is not fully implemented
-  --> $DIR/cfg_accessible.rs:16:18
-   |
-LL | #[cfg_accessible(m::NonExistent)]
-   |                  ^^^^^^^^^^^^^^
+LL |     NonExistingPrivate;
+   |     ^^^^^^^^^^^^^^^^^^ not found in this scope
 
-error: not sure whether the path is accessible or not
-  --> $DIR/cfg_accessible.rs:37:18
-   |
-LL | #[cfg_accessible(S::field)]
-   |                  ^^^^^^^^
-   |
-note: `cfg_accessible` is not fully implemented
-  --> $DIR/cfg_accessible.rs:37:18
+error[E0425]: cannot find value `NonExistingTraitAlias` in this scope
+  --> $DIR/cfg_accessible.rs:54:5
    |
-LL | #[cfg_accessible(S::field)]
-   |                  ^^^^^^^^
+LL |     NonExistingTraitAlias;
+   |     ^^^^^^^^^^^^^^^^^^^^^ not found in this scope
 
 error: aborting due to 3 previous errors
 
+For more information about this error, try `rustc --explain E0425`.