Fix exposing fields marked unstable or doc hidden

compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs

@@ -692,11 +692,11 @@ impl<'tcx> Constructor<'tcx> {
     }
 
     /// Checks if the `Constructor` is a `Constructor::Variant` with a `#[doc(hidden)]`
-    /// attribute.
+    /// attribute from a type not local to the current crate.
     pub(super) fn is_doc_hidden_variant(&self, pcx: PatCtxt<'_, '_, 'tcx>) -> bool {
         if let Constructor::Variant(idx) = self && let ty::Adt(adt, _) = pcx.ty.kind() {
-            let variant_def_id = adt.variant(*idx).def_id;
-            return pcx.cx.tcx.is_doc_hidden(variant_def_id);
+            let variant_def_id = adt.variants()[*idx].def_id;
+            return pcx.cx.tcx.is_doc_hidden(variant_def_id) && !variant_def_id.is_local();
         }
         false
     }

compiler/rustc_typeck/src/check/pat.rs

@@ -11,6 +11,7 @@ use rustc_hir::pat_util::EnumerateAndAdjustIterator;
 use rustc_hir::{HirId, Pat, PatKind};
 use rustc_infer::infer;
 use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
+use rustc_middle::middle::stability::EvalResult;
 use rustc_middle::ty::{self, Adt, BindingMode, Ty, TypeFoldable};
 use rustc_session::lint::builtin::NON_EXHAUSTIVE_OMITTED_PATTERNS;
 use rustc_span::hygiene::DesugaringKind;
@@ -1308,6 +1309,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 .copied()
                 .filter(|(field, _)| {
                     field.vis.is_accessible_from(tcx.parent_module(pat.hir_id).to_def_id(), tcx)
+                        && !matches!(
+                            tcx.eval_stability(field.did, None, DUMMY_SP, None),
+                            EvalResult::Deny { .. }
+                        )
+                        // We only want to report the error if it is hidden and not local
+                        && !(tcx.is_doc_hidden(field.did) && !field.did.is_local())
                 })
                 .collect();
 

src/test/ui/pattern/usefulness/auxiliary/hidden.rs

@@ -1,6 +1,14 @@
-pub enum Foo {
+pub enum HiddenEnum {
     A,
     B,
     #[doc(hidden)]
     C,
 }
+
+#[derive(Default)]
+pub struct HiddenStruct {
+    pub one: u8,
+    pub two: bool,
+    #[doc(hidden)]
+    pub hide: usize,
+}

src/test/ui/pattern/usefulness/auxiliary/unstable.rs

@@ -2,11 +2,22 @@
 #![stable(feature = "stable_test_feature", since = "1.0.0")]
 
 #[stable(feature = "stable_test_feature", since = "1.0.0")]
-pub enum Foo {
+pub enum UnstableEnum {
     #[stable(feature = "stable_test_feature", since = "1.0.0")]
     Stable,
     #[stable(feature = "stable_test_feature", since = "1.0.0")]
     Stable2,
     #[unstable(feature = "unstable_test_feature", issue = "none")]
     Unstable,
 }
+
+#[derive(Default)]
+#[stable(feature = "stable_test_feature", since = "1.0.0")]
+pub struct UnstableStruct {
+    #[stable(feature = "stable_test_feature", since = "1.0.0")]
+    pub stable: bool,
+    #[stable(feature = "stable_test_feature", since = "1.0.0")]
+    pub stable2: usize,
+    #[unstable(feature = "unstable_test_feature", issue = "none")]
+    pub unstable: u8,
+}

src/test/ui/pattern/usefulness/doc-hidden-fields.rs

@@ -0,0 +1,26 @@
+// aux-build:hidden.rs
+
+extern crate hidden;
+
+use hidden::HiddenStruct;
+
+struct InCrate {
+    a: usize,
+    b: bool,
+    #[doc(hidden)]
+    im_hidden: u8
+}
+
+fn main() {
+    let HiddenStruct { one, two } = HiddenStruct::default();
+    //~^ pattern requires `..` due to inaccessible fields
+
+    let HiddenStruct { one } = HiddenStruct::default();
+    //~^ pattern does not mention field `two` and inaccessible fields
+
+    let HiddenStruct { one, hide } = HiddenStruct::default();
+    //~^ pattern does not mention field `two`
+
+    let InCrate { a, b } = InCrate { a: 0, b: false, im_hidden: 0 };
+    //~^ pattern does not mention field `im_hidden`
+}

src/test/ui/pattern/usefulness/doc-hidden-fields.stderr

@@ -0,0 +1,59 @@
+error: pattern requires `..` due to inaccessible fields
+  --> $DIR/doc-hidden-fields.rs:15:9
+   |
+LL |     let HiddenStruct { one, two } = HiddenStruct::default();
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: ignore the inaccessible and unused fields
+   |
+LL |     let HiddenStruct { one, two, .. } = HiddenStruct::default();
+   |                                ++++
+
+error[E0027]: pattern does not mention field `two` and inaccessible fields
+  --> $DIR/doc-hidden-fields.rs:18:9
+   |
+LL |     let HiddenStruct { one } = HiddenStruct::default();
+   |         ^^^^^^^^^^^^^^^^^^^^ missing field `two` and inaccessible fields
+   |
+help: include the missing field in the pattern and ignore the inaccessible fields
+   |
+LL |     let HiddenStruct { one, two, .. } = HiddenStruct::default();
+   |                           ~~~~~~~~~~~
+help: if you don't care about this missing field, you can explicitly ignore it
+   |
+LL |     let HiddenStruct { one, .. } = HiddenStruct::default();
+   |                           ~~~~~~
+
+error[E0027]: pattern does not mention field `two`
+  --> $DIR/doc-hidden-fields.rs:21:9
+   |
+LL |     let HiddenStruct { one, hide } = HiddenStruct::default();
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ missing field `two`
+   |
+help: include the missing field in the pattern
+   |
+LL |     let HiddenStruct { one, hide, two } = HiddenStruct::default();
+   |                                 ~~~~~~~
+help: if you don't care about this missing field, you can explicitly ignore it
+   |
+LL |     let HiddenStruct { one, hide, .. } = HiddenStruct::default();
+   |                                 ~~~~~~
+
+error[E0027]: pattern does not mention field `im_hidden`
+  --> $DIR/doc-hidden-fields.rs:24:9
+   |
+LL |     let InCrate { a, b } = InCrate { a: 0, b: false, im_hidden: 0 };
+   |         ^^^^^^^^^^^^^^^^ missing field `im_hidden`
+   |
+help: include the missing field in the pattern
+   |
+LL |     let InCrate { a, b, im_hidden } = InCrate { a: 0, b: false, im_hidden: 0 };
+   |                       ~~~~~~~~~~~~~
+help: if you don't care about this missing field, you can explicitly ignore it
+   |
+LL |     let InCrate { a, b, .. } = InCrate { a: 0, b: false, im_hidden: 0 };
+   |                       ~~~~~~
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0027`.

src/test/ui/pattern/usefulness/doc-hidden-non-exhaustive.rs

@@ -2,29 +2,42 @@
 
 extern crate hidden;
 
-use hidden::Foo;
+use hidden::HiddenEnum;
+
+enum InCrate {
+    A,
+    B,
+    #[doc(hidden)]
+    C,
+}
 
 fn main() {
-    match Foo::A {
-        Foo::A => {}
-        Foo::B => {}
+    match HiddenEnum::A {
+        HiddenEnum::A => {}
+        HiddenEnum::B => {}
     }
     //~^^^^ non-exhaustive patterns: `_` not covered
 
-    match Foo::A {
-        Foo::A => {}
-        Foo::C => {}
+    match HiddenEnum::A {
+        HiddenEnum::A => {}
+        HiddenEnum::C => {}
     }
     //~^^^^ non-exhaustive patterns: `B` not covered
 
-    match Foo::A {
-        Foo::A => {}
+    match HiddenEnum::A {
+        HiddenEnum::A => {}
     }
     //~^^^ non-exhaustive patterns: `B` and `_` not covered
 
     match None {
         None => {}
-        Some(Foo::A) => {}
+        Some(HiddenEnum::A) => {}
     }
     //~^^^^ non-exhaustive patterns: `Some(B)` and `Some(_)` not covered
+
+    match InCrate::A {
+        InCrate::A => {}
+        InCrate::B => {}
+    }
+    //~^^^^ non-exhaustive patterns: `C` not covered
 }

src/test/ui/pattern/usefulness/doc-hidden-non-exhaustive.stderr

@@ -1,81 +1,81 @@
 error[E0004]: non-exhaustive patterns: `_` not covered
-  --> $DIR/doc-hidden-non-exhaustive.rs:8:11
+  --> $DIR/doc-hidden-non-exhaustive.rs:15:11
    |
-LL |     match Foo::A {
-   |           ^^^^^^ pattern `_` not covered
+LL |     match HiddenEnum::A {
+   |           ^^^^^^^^^^^^^ pattern `_` not covered
    |
-note: `Foo` defined here
+note: `HiddenEnum` defined here
   --> $DIR/auxiliary/hidden.rs:1:1
    |
-LL | / pub enum Foo {
+LL | / pub enum HiddenEnum {
 LL | |     A,
 LL | |     B,
 LL | |     #[doc(hidden)]
 LL | |     C,
 LL | | }
    | |_^
-   = note: the matched value is of type `Foo`
+   = note: the matched value is of type `HiddenEnum`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         Foo::B => {}
+LL ~         HiddenEnum::B => {}
 LL +         _ => todo!()
    |
 
 error[E0004]: non-exhaustive patterns: `B` not covered
-  --> $DIR/doc-hidden-non-exhaustive.rs:14:11
+  --> $DIR/doc-hidden-non-exhaustive.rs:21:11
    |
-LL |     match Foo::A {
-   |           ^^^^^^ pattern `B` not covered
+LL |     match HiddenEnum::A {
+   |           ^^^^^^^^^^^^^ pattern `B` not covered
    |
-note: `Foo` defined here
+note: `HiddenEnum` defined here
   --> $DIR/auxiliary/hidden.rs:3:5
    |
-LL | / pub enum Foo {
+LL | / pub enum HiddenEnum {
 LL | |     A,
 LL | |     B,
    | |     ^ not covered
 LL | |     #[doc(hidden)]
 LL | |     C,
 LL | | }
    | |_-
-   = note: the matched value is of type `Foo`
+   = note: the matched value is of type `HiddenEnum`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         Foo::C => {}
+LL ~         HiddenEnum::C => {}
 LL +         B => todo!()
    |
 
 error[E0004]: non-exhaustive patterns: `B` and `_` not covered
-  --> $DIR/doc-hidden-non-exhaustive.rs:20:11
+  --> $DIR/doc-hidden-non-exhaustive.rs:27:11
    |
-LL |     match Foo::A {
-   |           ^^^^^^ patterns `B` and `_` not covered
+LL |     match HiddenEnum::A {
+   |           ^^^^^^^^^^^^^ patterns `B` and `_` not covered
    |
-note: `Foo` defined here
+note: `HiddenEnum` defined here
   --> $DIR/auxiliary/hidden.rs:3:5
    |
-LL | / pub enum Foo {
+LL | / pub enum HiddenEnum {
 LL | |     A,
 LL | |     B,
    | |     ^ not covered
 LL | |     #[doc(hidden)]
 LL | |     C,
 LL | | }
    | |_-
-   = note: the matched value is of type `Foo`
+   = note: the matched value is of type `HiddenEnum`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
    |
-LL ~         Foo::A => {}
+LL ~         HiddenEnum::A => {}
 LL +         B | _ => todo!()
    |
 
 error[E0004]: non-exhaustive patterns: `Some(B)` and `Some(_)` not covered
-  --> $DIR/doc-hidden-non-exhaustive.rs:25:11
+  --> $DIR/doc-hidden-non-exhaustive.rs:32:11
    |
 LL |     match None {
    |           ^^^^ patterns `Some(B)` and `Some(_)` not covered
    |
-note: `Option<Foo>` defined here
+note: `Option<HiddenEnum>` defined here
   --> $SRC_DIR/core/src/option.rs:LL:COL
    |
 LL | / pub enum Option<T> {
@@ -87,13 +87,34 @@ LL | |     Some(#[stable(feature = "rust1", since = "1.0.0")] T),
    | |     ^^^^ not covered
 LL | | }
    | |_-
-   = note: the matched value is of type `Option<Foo>`
+   = note: the matched value is of type `Option<HiddenEnum>`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
    |
-LL ~         Some(Foo::A) => {}
+LL ~         Some(HiddenEnum::A) => {}
 LL +         Some(B) | Some(_) => todo!()
    |
 
-error: aborting due to 4 previous errors
+error[E0004]: non-exhaustive patterns: `C` not covered
+  --> $DIR/doc-hidden-non-exhaustive.rs:38:11
+   |
+LL |     match InCrate::A {
+   |           ^^^^^^^^^^ pattern `C` not covered
+   |
+note: `InCrate` defined here
+  --> $DIR/doc-hidden-non-exhaustive.rs:11:5
+   |
+LL | enum InCrate {
+   |      -------
+...
+LL |     C,
+   |     ^ not covered
+   = note: the matched value is of type `InCrate`
+help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
+   |
+LL ~         InCrate::B => {}
+LL +         C => todo!()
+   |
+
+error: aborting due to 5 previous errors
 
 For more information about this error, try `rustc --explain E0004`.

src/test/ui/pattern/usefulness/stable-gated-fields.rs

@@ -0,0 +1,16 @@
+// aux-build:unstable.rs
+
+extern crate unstable;
+
+use unstable::UnstableStruct;
+
+fn main() {
+    let UnstableStruct { stable } = UnstableStruct::default();
+    //~^ pattern does not mention field `stable2` and inaccessible fields
+
+    let UnstableStruct { stable, stable2 } = UnstableStruct::default();
+    //~^ pattern requires `..` due to inaccessible fields
+
+    // OK: stable field is matched
+    let UnstableStruct { stable, stable2, .. } = UnstableStruct::default();
+}