Auto merge of #97391 - Urgau:cfg_accessible, r=petrochenkov

Handle more cases in cfg_accessible

This PR tries to handle more cases in the cfg_accessible implementation by only emitting a "not sure" error only if we have partially resolved a path.

This PR also adds many tests for the "not sure" cases and for private items.

r? `@petrochenkov`

compiler/rustc_resolve/src/macros.rs

@@ -443,11 +443,22 @@ impl<'a> ResolverExpand for Resolver<'a> {
                 PathResult::NonModule(partial_res) if partial_res.unresolved_segments() == 0 => {
                     return Ok(true);
                 }
+                PathResult::NonModule(..) |
+                // HACK(Urgau): This shouldn't be necessary
+                PathResult::Failed { is_error_from_last_segment: false, .. } => {
+                    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 +467,6 @@ impl<'a> ResolverExpand for Resolver<'a> {
             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-bugs.rs

@@ -0,0 +1,18 @@
+// This test is a collection of test that should pass.
+//
+// check-fail
+
+#![feature(cfg_accessible)]
+#![feature(trait_alias)]
+
+trait TraitAlias = std::fmt::Debug + Send;
+
+// FIXME: Currently shows "cannot determine" but should be `false`
+#[cfg_accessible(unresolved)] //~ ERROR cannot determine
+const C: bool = true;
+
+// FIXME: Currently shows "not sure" but should be `false`
+#[cfg_accessible(TraitAlias::unresolved)] //~ ERROR not sure whether the path is accessible or not
+const D: bool = true;
+
+fn main() {}

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

@@ -0,0 +1,16 @@
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-bugs.rs:15:18
+   |
+LL | #[cfg_accessible(TraitAlias::unresolved)]
+   |                  ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: cannot determine whether the path is accessible or not
+  --> $DIR/cfg_accessible-bugs.rs:11:1
+   |
+LL | #[cfg_accessible(unresolved)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+

src/test/ui/conditional-compilation/cfg_accessible-not_sure.edition2015.stderr

@@ -0,0 +1,122 @@
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:14:18
+   |
+LL | #[cfg_accessible(Struct::existing)]
+   |                  ^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:16:18
+   |
+LL | #[cfg_accessible(Struct::unresolved)]
+   |                  ^^^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:25:18
+   |
+LL | #[cfg_accessible(Union::existing)]
+   |                  ^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:27:18
+   |
+LL | #[cfg_accessible(Union::unresolved)]
+   |                  ^^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:36:18
+   |
+LL | #[cfg_accessible(Enum::Existing::existing)]
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:38:18
+   |
+LL | #[cfg_accessible(Enum::Existing::unresolved)]
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:40:18
+   |
+LL | #[cfg_accessible(Enum::unresolved)]
+   |                  ^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:50:18
+   |
+LL | #[cfg_accessible(Trait::existing)]
+   |                  ^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:52:18
+   |
+LL | #[cfg_accessible(Trait::unresolved)]
+   |                  ^^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:59:18
+   |
+LL | #[cfg_accessible(TypeAlias::existing)]
+   |                  ^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:61:18
+   |
+LL | #[cfg_accessible(TypeAlias::unresolved)]
+   |                  ^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:70:18
+   |
+LL | #[cfg_accessible(ForeignType::unresolved)]
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:79:18
+   |
+LL | #[cfg_accessible(AssocType::AssocType::unresolved)]
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:84:18
+   |
+LL | #[cfg_accessible(u8::unresolved)]
+   |                  ^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:86:18
+   |
+LL | #[cfg_accessible(u8::is_ascii)]
+   |                  ^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: aborting due to 15 previous errors
+

src/test/ui/conditional-compilation/cfg_accessible-not_sure.edition2021.stderr

@@ -0,0 +1,122 @@
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:14:18
+   |
+LL | #[cfg_accessible(Struct::existing)]
+   |                  ^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:16:18
+   |
+LL | #[cfg_accessible(Struct::unresolved)]
+   |                  ^^^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:25:18
+   |
+LL | #[cfg_accessible(Union::existing)]
+   |                  ^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:27:18
+   |
+LL | #[cfg_accessible(Union::unresolved)]
+   |                  ^^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:36:18
+   |
+LL | #[cfg_accessible(Enum::Existing::existing)]
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:38:18
+   |
+LL | #[cfg_accessible(Enum::Existing::unresolved)]
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:40:18
+   |
+LL | #[cfg_accessible(Enum::unresolved)]
+   |                  ^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:50:18
+   |
+LL | #[cfg_accessible(Trait::existing)]
+   |                  ^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:52:18
+   |
+LL | #[cfg_accessible(Trait::unresolved)]
+   |                  ^^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:59:18
+   |
+LL | #[cfg_accessible(TypeAlias::existing)]
+   |                  ^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:61:18
+   |
+LL | #[cfg_accessible(TypeAlias::unresolved)]
+   |                  ^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:70:18
+   |
+LL | #[cfg_accessible(ForeignType::unresolved)]
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:79:18
+   |
+LL | #[cfg_accessible(AssocType::AssocType::unresolved)]
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:84:18
+   |
+LL | #[cfg_accessible(u8::unresolved)]
+   |                  ^^^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: not sure whether the path is accessible or not
+  --> $DIR/cfg_accessible-not_sure.rs:86:18
+   |
+LL | #[cfg_accessible(u8::is_ascii)]
+   |                  ^^^^^^^^^^^^
+   |
+   = note: the type may have associated items, but we are currently not checking them
+
+error: aborting due to 15 previous errors
+

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

@@ -0,0 +1,89 @@
+// revisions: edition2015 edition2021
+// [edition2015]compile-flags: --edition=2015
+// [edition2021]compile-flags: --edition=2021
+
+#![feature(extern_types)]
+#![feature(cfg_accessible)]
+
+// Struct::unresolved - error
+
+struct Struct {
+    existing: u8,
+}
+
+#[cfg_accessible(Struct::existing)] //~ ERROR not sure
+const A: bool = true;
+#[cfg_accessible(Struct::unresolved)] //~ ERROR not sure
+const B: bool = true;
+
+// Union::unresolved - error
+
+struct Union {
+    existing: u8,
+}
+
+#[cfg_accessible(Union::existing)] //~ ERROR not sure
+const A: bool = true;
+#[cfg_accessible(Union::unresolved)] //~ ERROR not sure
+const B: bool = true;
+
+// Enum::unresolved - error
+
+enum Enum {
+    Existing { existing: u8 },
+}
+
+#[cfg_accessible(Enum::Existing::existing)] //~ ERROR not sure
+const A: bool = true;
+#[cfg_accessible(Enum::Existing::unresolved)] //~ ERROR not sure
+const B: bool = true;
+#[cfg_accessible(Enum::unresolved)] //~ ERROR not sure
+const C: bool = true;
+
+// Trait::unresolved - false or error, depending on edition (error if you can write Trait::foo
+// instead of <dyn Trait>::foo for methods like impl dyn Trait { fn foo() {} })
+
+trait Trait {}
+impl dyn Trait { fn existing() {} }
+
+// FIXME: Should be a error for edition > 2015
+#[cfg_accessible(Trait::existing)] //~ ERROR not sure
+const A: bool = true;
+#[cfg_accessible(Trait::unresolved)] //~ ERROR not sure
+const B: bool = true;
+
+// TypeAlias::unresolved - error
+
+type TypeAlias = Struct;
+
+#[cfg_accessible(TypeAlias::existing)] //~ ERROR not sure
+const A: bool = true;
+#[cfg_accessible(TypeAlias::unresolved)] //~ ERROR not sure
+const B: bool = true;
+
+// ForeignType::unresolved - error
+
+extern {
+    type ForeignType;
+}
+
+#[cfg_accessible(ForeignType::unresolved)] //~ ERROR not sure
+const A: bool = true;
+
+// AssocType::unresolved - error
+
+trait AssocType {
+    type AssocType;
+}
+
+#[cfg_accessible(AssocType::AssocType::unresolved)] //~ ERROR not sure
+const A: bool = true;
+
+// PrimitiveType::unresolved - error
+
+#[cfg_accessible(u8::unresolved)] //~ ERROR not sure
+const A: bool = true;
+#[cfg_accessible(u8::is_ascii)] //~ ERROR not sure
+const B: bool = true;
+
+fn main() {}

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

@@ -0,0 +1,21 @@
+// check-pass
+
+#![feature(cfg_accessible)]
+
+mod private {
+    struct Struct;
+    enum Enum{}
+    union Union{_a:u8}
+}
+
+#[cfg_accessible(private::Struct)]
+const A: bool = true;
+
+#[cfg_accessible(private::Enum)]
+const A: bool = true;
+
+#[cfg_accessible(private::Union)]
+const A: bool = true;
+
+const A: bool = false; // Will conflict if any of those is accessible
+fn main() {}

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 @@ macro_rules! generate_accessible_expanded {
 
 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

@@ -1,38 +1,27 @@
-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
+error[E0425]: cannot find value `NonExistingTraitAlias` in this scope
+  --> $DIR/cfg_accessible.rs:54:5
    |
-LL | #[cfg_accessible(S::field)]
-   |                  ^^^^^^^^
-   |
-note: `cfg_accessible` is not fully implemented
-  --> $DIR/cfg_accessible.rs:37:18
-   |
-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`.