add ui testcase for issue 82772

compiler/rustc_typeck/src/check/pat.rs

@@ -1176,6 +1176,7 @@ fn check_struct_pat_fields(
         let mut no_field_errors = true;
 
         let mut inexistent_fields = vec![];
+        let mut invisible_fields = vec![];
         // Typecheck each field.
         for field in fields {
             let span = field.span;
@@ -1191,6 +1192,12 @@ fn check_struct_pat_fields(
                     field_map
                         .get(&ident)
                         .map(|(i, f)| {
+                            if !f
+                                .vis
+                                .is_accessible_from(tcx.parent_module(pat.hir_id).to_def_id(), tcx)
+                            {
+                                invisible_fields.push(field.ident);
+                            }
                             self.write_field_index(field.hir_id, *i);
                             self.tcx.check_stability(f.did, Some(pat.hir_id), span);
                             self.field_ty(span, f, substs)
@@ -1281,6 +1288,13 @@ fn check_struct_pat_fields(
                     self.error_tuple_variant_index_shorthand(variant, pat, fields)
                 {
                     err.emit();
+                } else if !invisible_fields.is_empty() {
+                    let mut err = self.error_invisible_fields(
+                        adt.variant_descr(),
+                        &invisible_fields,
+                        variant,
+                    );
+                    err.emit();
                 }
             }
         }
@@ -1359,6 +1373,41 @@ fn error_field_already_bound(&self, span: Span, ident: Ident, other_field: Span)
         .emit();
     }
 
+    fn error_invisible_fields(
+        &self,
+        kind_name: &str,
+        invisible_fields: &[Ident],
+        variant: &ty::VariantDef,
+    ) -> DiagnosticBuilder<'tcx> {
+        let spans = invisible_fields.iter().map(|ident| ident.span).collect::<Vec<_>>();
+        let (field_names, t) = if invisible_fields.len() == 1 {
+            (format!("a field named `{}`", invisible_fields[0]), "is")
+        } else {
+            (
+                format!(
+                    "fields named {}",
+                    invisible_fields
+                        .iter()
+                        .map(|ident| format!("`{}`", ident))
+                        .collect::<Vec<String>>()
+                        .join(", ")
+                ),
+                "are",
+            )
+        };
+        let err = struct_span_err!(
+            self.tcx.sess,
+            spans,
+            E0603,
+            "cannot match on {} of {} `{}`, which {} not accessible in current scope",
+            field_names,
+            kind_name,
+            self.tcx.def_path_str(variant.def_id),
+            t
+        );
+        err
+    }
+
     fn error_inexistent_fields(
         &self,
         kind_name: &str,

src/test/ui/structs/struct-variant-privacy-xc.rs

@@ -1,9 +1,11 @@
 // aux-build:struct_variant_privacy.rs
 extern crate struct_variant_privacy;
 
-fn f(b: struct_variant_privacy::Bar) { //~ ERROR enum `Bar` is private
+fn f(b: struct_variant_privacy::Bar) {
+    //~^ ERROR enum `Bar` is private
     match b {
-        struct_variant_privacy::Bar::Baz { a: _a } => {} //~ ERROR enum `Bar` is private
+        struct_variant_privacy::Bar::Baz { a: _a } => {} //~ ERROR cannot match on
+                                                         //~^ ERROR enum `Bar` is private
     }
 }
 

src/test/ui/structs/struct-variant-privacy-xc.stderr

@@ -11,7 +11,7 @@ LL | enum Bar {
    | ^^^^^^^^
 
 error[E0603]: enum `Bar` is private
-  --> $DIR/struct-variant-privacy-xc.rs:6:33
+  --> $DIR/struct-variant-privacy-xc.rs:7:33
    |
 LL |         struct_variant_privacy::Bar::Baz { a: _a } => {}
    |                                 ^^^ private enum
@@ -22,6 +22,12 @@ note: the enum `Bar` is defined here
 LL | enum Bar {
    | ^^^^^^^^
 
-error: aborting due to 2 previous errors
+error[E0603]: cannot match on a field named `a` of variant `struct_variant_privacy::Bar::Baz`, which is not accessible in current scope
+  --> $DIR/struct-variant-privacy-xc.rs:7:44
+   |
+LL |         struct_variant_privacy::Bar::Baz { a: _a } => {}
+   |                                            ^
+
+error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0603`.

src/test/ui/structs/struct-variant-privacy.rs

@@ -1,12 +1,14 @@
 mod foo {
     enum Bar {
-        Baz { a: isize }
+        Baz { a: isize },
     }
 }
 
-fn f(b: foo::Bar) { //~ ERROR enum `Bar` is private
+fn f(b: foo::Bar) {
+    //~^ ERROR enum `Bar` is private
     match b {
         foo::Bar::Baz { a: _a } => {} //~ ERROR enum `Bar` is private
+                                      //~^ ERROR cannot match on
     }
 }
 

src/test/ui/structs/struct-variant-privacy.stderr

@@ -11,7 +11,7 @@ LL |     enum Bar {
    |     ^^^^^^^^
 
 error[E0603]: enum `Bar` is private
-  --> $DIR/struct-variant-privacy.rs:9:14
+  --> $DIR/struct-variant-privacy.rs:10:14
    |
 LL |         foo::Bar::Baz { a: _a } => {}
    |              ^^^ private enum
@@ -22,6 +22,12 @@ note: the enum `Bar` is defined here
 LL |     enum Bar {
    |     ^^^^^^^^
 
-error: aborting due to 2 previous errors
+error[E0603]: cannot match on a field named `a` of variant `Bar::Baz`, which is not accessible in current scope
+  --> $DIR/struct-variant-privacy.rs:10:25
+   |
+LL |         foo::Bar::Baz { a: _a } => {}
+   |                         ^
+
+error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0603`.

src/test/ui/typeck/issue-82772.rs

@@ -0,0 +1,13 @@
+// edition:2018
+
+fn main() {
+    use a::LocalModPrivateStruct;
+    let Box { 1: _, .. }: Box<()>; //~ ERROR cannot match on
+    let LocalModPrivateStruct { 1: _, .. } = LocalModPrivateStruct::default();
+    //~^ ERROR cannot match on
+}
+
+mod a {
+    #[derive(Default)]
+    pub struct LocalModPrivateStruct(u8, u8);
+}

src/test/ui/typeck/issue-82772.stderr

@@ -0,0 +1,15 @@
+error[E0603]: cannot match on a field named `1` of struct `Box`, which is not accessible in current scope
+  --> $DIR/issue-82772.rs:5:15
+   |
+LL |     let Box { 1: _, .. }: Box<()>;
+   |               ^
+
+error[E0603]: cannot match on a field named `1` of struct `LocalModPrivateStruct`, which is not accessible in current scope
+  --> $DIR/issue-82772.rs:6:33
+   |
+LL |     let LocalModPrivateStruct { 1: _, .. } = LocalModPrivateStruct::default();
+   |                                 ^
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0603`.