Rollup merge of #106579 - estebank:issue-52144, r=Nilstrieb

Suggest making private tuple struct field public

Fix #52144.

compiler/rustc_resolve/src/build_reduced_graph.rs

@@ -334,6 +334,15 @@ fn insert_field_names_local(&mut self, def_id: DefId, vdata: &ast::VariantData)
         self.r.field_names.insert(def_id, field_names);
     }
 
+    fn insert_field_visibilities_local(&mut self, def_id: DefId, vdata: &ast::VariantData) {
+        let field_vis = vdata
+            .fields()
+            .iter()
+            .map(|field| field.vis.span.until(field.ident.map_or(field.ty.span, |i| i.span)))
+            .collect();
+        self.r.field_visibility_spans.insert(def_id, field_vis);
+    }
+
     fn insert_field_names_extern(&mut self, def_id: DefId) {
         let field_names =
             self.r.cstore().struct_field_names_untracked(def_id, self.r.session).collect();
@@ -737,6 +746,7 @@ fn build_reduced_graph_for_item(&mut self, item: &'b Item) {
 
                 // Record field names for error reporting.
                 self.insert_field_names_local(def_id, vdata);
+                self.insert_field_visibilities_local(def_id, vdata);
 
                 // If this is a tuple or unit struct, define a name
                 // in the value namespace as well.
@@ -770,6 +780,8 @@ fn build_reduced_graph_for_item(&mut self, item: &'b Item) {
                         Res::Def(DefKind::Ctor(CtorOf::Struct, ctor_kind), ctor_def_id.to_def_id());
                     self.r.define(parent, ident, ValueNS, (ctor_res, ctor_vis, sp, expansion));
                     self.r.visibilities.insert(ctor_def_id, ctor_vis);
+                    // We need the field visibility spans also for the constructor for E0603.
+                    self.insert_field_visibilities_local(ctor_def_id.to_def_id(), vdata);
 
                     self.r
                         .struct_constructors
@@ -783,6 +795,7 @@ fn build_reduced_graph_for_item(&mut self, item: &'b Item) {
 
                 // Record field names for error reporting.
                 self.insert_field_names_local(def_id, vdata);
+                self.insert_field_visibilities_local(def_id, vdata);
             }
 
             ItemKind::Trait(..) => {
@@ -1510,6 +1523,7 @@ fn visit_variant(&mut self, variant: &'b ast::Variant) {
 
         // Record field names for error reporting.
         self.insert_field_names_local(def_id.to_def_id(), &variant.data);
+        self.insert_field_visibilities_local(def_id.to_def_id(), &variant.data);
 
         visit::walk_variant(self, variant);
     }

compiler/rustc_resolve/src/diagnostics.rs

@@ -6,7 +6,9 @@
 use rustc_ast_pretty::pprust;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::struct_span_err;
-use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, MultiSpan};
+use rustc_errors::{
+    pluralize, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, MultiSpan,
+};
 use rustc_feature::BUILTIN_ATTRIBUTES;
 use rustc_hir::def::Namespace::{self, *};
 use rustc_hir::def::{self, CtorKind, CtorOf, DefKind, NonMacroAttrKind, PerNS};
@@ -1604,6 +1606,16 @@ fn report_privacy_error(&self, privacy_error: &PrivacyError<'_>) {
         err.span_label(ident.span, &format!("private {}", descr));
         if let Some(span) = ctor_fields_span {
             err.span_label(span, "a constructor is private if any of the fields is private");
+            if let Res::Def(_, d) = res && let Some(fields) = self.field_visibility_spans.get(&d) {
+                err.multipart_suggestion_verbose(
+                    &format!(
+                        "consider making the field{} publicly accessible",
+                        pluralize!(fields.len())
+                    ),
+                    fields.iter().map(|span| (*span, "pub ".to_string())).collect(),
+                    Applicability::MaybeIncorrect,
+                );
+            }
         }
 
         // Print the whole import chain to make it easier to see what happens.

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -1451,6 +1451,17 @@ fn smart_resolve_context_dependent_help(
                         .collect();
 
                     if non_visible_spans.len() > 0 {
+                        if let Some(fields) = self.r.field_visibility_spans.get(&def_id) {
+                            err.multipart_suggestion_verbose(
+                                &format!(
+                                    "consider making the field{} publicly accessible",
+                                    pluralize!(fields.len())
+                                ),
+                                fields.iter().map(|span| (*span, "pub ".to_string())).collect(),
+                                Applicability::MaybeIncorrect,
+                            );
+                        }
+
                         let mut m: MultiSpan = non_visible_spans.clone().into();
                         non_visible_spans
                             .into_iter()

compiler/rustc_resolve/src/lib.rs

@@ -881,6 +881,10 @@ pub struct Resolver<'a> {
     /// Used for hints during error reporting.
     field_names: FxHashMap<DefId, Vec<Spanned<Symbol>>>,
 
+    /// Span of the privacy modifier in fields of an item `DefId` accessible with dot syntax.
+    /// Used for hints during error reporting.
+    field_visibility_spans: FxHashMap<DefId, Vec<Span>>,
+
     /// All imports known to succeed or fail.
     determined_imports: Vec<&'a Import<'a>>,
 
@@ -1268,6 +1272,7 @@ pub fn new(
 
             has_self: FxHashSet::default(),
             field_names: FxHashMap::default(),
+            field_visibility_spans: FxHashMap::default(),
 
             determined_imports: Vec::new(),
             indeterminate_imports: Vec::new(),

tests/ui/privacy/issue-75906.stderr

@@ -9,6 +9,10 @@ note: constructor is not visible here due to private fields
    |
 LL |     pub struct Bar(u8);
    |                    ^^ private field
+help: consider making the field publicly accessible
+   |
+LL |     pub struct Bar(pub u8);
+   |                    +++
 
 error: aborting due to previous error
 

tests/ui/privacy/issue-75907.rs

@@ -2,7 +2,7 @@
 
 mod foo {
     pub(crate) struct Foo(u8);
-    pub(crate) struct Bar(pub u8, u8, Foo);
+    pub(crate) struct Bar(pub u8, pub(in crate::foo) u8, Foo);
 
     pub(crate) fn make_bar() -> Bar {
         Bar(1, 12, Foo(10))

tests/ui/privacy/issue-75907.stderr

@@ -11,6 +11,10 @@ LL |     let Bar(x, y, Foo(z)) = make_bar();
    |                ^  ^^^^^^ private field
    |                |
    |                private field
+help: consider making the fields publicly accessible
+   |
+LL |     pub(crate) struct Bar(pub u8, pub u8, pub Foo);
+   |                           ~~~     ~~~     +++
 
 error[E0532]: cannot match against a tuple struct which contains private fields
   --> $DIR/issue-75907.rs:15:19
@@ -23,6 +27,10 @@ note: constructor is not visible here due to private fields
    |
 LL |     let Bar(x, y, Foo(z)) = make_bar();
    |                       ^ private field
+help: consider making the field publicly accessible
+   |
+LL |     pub(crate) struct Foo(pub u8);
+   |                           +++
 
 error: aborting due to 2 previous errors
 

tests/ui/privacy/privacy5.stderr

@@ -12,6 +12,10 @@ note: the tuple struct constructor `A` is defined here
    |
 LL |     pub struct A(());
    |     ^^^^^^^^^^^^^^^^^
+help: consider making the field publicly accessible
+   |
+LL |     pub struct A(pub ());
+   |                  +++
 
 error[E0603]: tuple struct constructor `B` is private
   --> $DIR/privacy5.rs:52:16
@@ -27,6 +31,10 @@ note: the tuple struct constructor `B` is defined here
    |
 LL |     pub struct B(isize);
    |     ^^^^^^^^^^^^^^^^^^^^
+help: consider making the field publicly accessible
+   |
+LL |     pub struct B(pub isize);
+   |                  +++
 
 error[E0603]: tuple struct constructor `C` is private
   --> $DIR/privacy5.rs:53:16
@@ -42,6 +50,10 @@ note: the tuple struct constructor `C` is defined here
    |
 LL |     pub struct C(pub isize, isize);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider making the fields publicly accessible
+   |
+LL |     pub struct C(pub isize, pub isize);
+   |                  ~~~        +++
 
 error[E0603]: tuple struct constructor `A` is private
   --> $DIR/privacy5.rs:56:12
@@ -57,6 +69,10 @@ note: the tuple struct constructor `A` is defined here
    |
 LL |     pub struct A(());
    |     ^^^^^^^^^^^^^^^^^
+help: consider making the field publicly accessible
+   |
+LL |     pub struct A(pub ());
+   |                  +++
 
 error[E0603]: tuple struct constructor `A` is private
   --> $DIR/privacy5.rs:57:12
@@ -72,6 +88,10 @@ note: the tuple struct constructor `A` is defined here
    |
 LL |     pub struct A(());
    |     ^^^^^^^^^^^^^^^^^
+help: consider making the field publicly accessible
+   |
+LL |     pub struct A(pub ());
+   |                  +++
 
 error[E0603]: tuple struct constructor `A` is private
   --> $DIR/privacy5.rs:58:18
@@ -87,6 +107,10 @@ note: the tuple struct constructor `A` is defined here
    |
 LL |     pub struct A(());
    |     ^^^^^^^^^^^^^^^^^
+help: consider making the field publicly accessible
+   |
+LL |     pub struct A(pub ());
+   |                  +++
 
 error[E0603]: tuple struct constructor `A` is private
   --> $DIR/privacy5.rs:59:18
@@ -102,6 +126,10 @@ note: the tuple struct constructor `A` is defined here
    |
 LL |     pub struct A(());
    |     ^^^^^^^^^^^^^^^^^
+help: consider making the field publicly accessible
+   |
+LL |     pub struct A(pub ());
+   |                  +++
 
 error[E0603]: tuple struct constructor `B` is private
   --> $DIR/privacy5.rs:61:12
@@ -117,6 +145,10 @@ note: the tuple struct constructor `B` is defined here
    |
 LL |     pub struct B(isize);
    |     ^^^^^^^^^^^^^^^^^^^^
+help: consider making the field publicly accessible
+   |
+LL |     pub struct B(pub isize);
+   |                  +++
 
 error[E0603]: tuple struct constructor `B` is private
   --> $DIR/privacy5.rs:62:12
@@ -132,6 +164,10 @@ note: the tuple struct constructor `B` is defined here
    |
 LL |     pub struct B(isize);
    |     ^^^^^^^^^^^^^^^^^^^^
+help: consider making the field publicly accessible
+   |
+LL |     pub struct B(pub isize);
+   |                  +++
 
 error[E0603]: tuple struct constructor `B` is private
   --> $DIR/privacy5.rs:63:18
@@ -147,6 +183,10 @@ note: the tuple struct constructor `B` is defined here
    |
 LL |     pub struct B(isize);
    |     ^^^^^^^^^^^^^^^^^^^^
+help: consider making the field publicly accessible
+   |
+LL |     pub struct B(pub isize);
+   |                  +++
 
 error[E0603]: tuple struct constructor `B` is private
   --> $DIR/privacy5.rs:64:18
@@ -162,6 +202,10 @@ note: the tuple struct constructor `B` is defined here
    |
 LL |     pub struct B(isize);
    |     ^^^^^^^^^^^^^^^^^^^^
+help: consider making the field publicly accessible
+   |
+LL |     pub struct B(pub isize);
+   |                  +++
 
 error[E0603]: tuple struct constructor `B` is private
   --> $DIR/privacy5.rs:65:18
@@ -177,6 +221,10 @@ note: the tuple struct constructor `B` is defined here
    |
 LL |     pub struct B(isize);
    |     ^^^^^^^^^^^^^^^^^^^^
+help: consider making the field publicly accessible
+   |
+LL |     pub struct B(pub isize);
+   |                  +++
 
 error[E0603]: tuple struct constructor `B` is private
   --> $DIR/privacy5.rs:65:32
@@ -192,6 +240,10 @@ note: the tuple struct constructor `B` is defined here
    |
 LL |     pub struct B(isize);
    |     ^^^^^^^^^^^^^^^^^^^^
+help: consider making the field publicly accessible
+   |
+LL |     pub struct B(pub isize);
+   |                  +++
 
 error[E0603]: tuple struct constructor `C` is private
   --> $DIR/privacy5.rs:68:12
@@ -207,6 +259,10 @@ note: the tuple struct constructor `C` is defined here
    |
 LL |     pub struct C(pub isize, isize);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider making the fields publicly accessible
+   |
+LL |     pub struct C(pub isize, pub isize);
+   |                  ~~~        +++
 
 error[E0603]: tuple struct constructor `C` is private
   --> $DIR/privacy5.rs:69:12
@@ -222,6 +278,10 @@ note: the tuple struct constructor `C` is defined here
    |
 LL |     pub struct C(pub isize, isize);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider making the fields publicly accessible
+   |
+LL |     pub struct C(pub isize, pub isize);
+   |                  ~~~        +++
 
 error[E0603]: tuple struct constructor `C` is private
   --> $DIR/privacy5.rs:70:12
@@ -237,6 +297,10 @@ note: the tuple struct constructor `C` is defined here
    |
 LL |     pub struct C(pub isize, isize);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider making the fields publicly accessible
+   |
+LL |     pub struct C(pub isize, pub isize);
+   |                  ~~~        +++
 
 error[E0603]: tuple struct constructor `C` is private
   --> $DIR/privacy5.rs:71:12
@@ -252,6 +316,10 @@ note: the tuple struct constructor `C` is defined here
    |
 LL |     pub struct C(pub isize, isize);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider making the fields publicly accessible
+   |
+LL |     pub struct C(pub isize, pub isize);
+   |                  ~~~        +++
 
 error[E0603]: tuple struct constructor `C` is private
   --> $DIR/privacy5.rs:72:18
@@ -267,6 +335,10 @@ note: the tuple struct constructor `C` is defined here
    |
 LL |     pub struct C(pub isize, isize);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider making the fields publicly accessible
+   |
+LL |     pub struct C(pub isize, pub isize);
+   |                  ~~~        +++
 
 error[E0603]: tuple struct constructor `C` is private
   --> $DIR/privacy5.rs:73:18
@@ -282,6 +354,10 @@ note: the tuple struct constructor `C` is defined here
    |
 LL |     pub struct C(pub isize, isize);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider making the fields publicly accessible
+   |
+LL |     pub struct C(pub isize, pub isize);
+   |                  ~~~        +++
 
 error[E0603]: tuple struct constructor `C` is private
   --> $DIR/privacy5.rs:74:18
@@ -297,6 +373,10 @@ note: the tuple struct constructor `C` is defined here
    |
 LL |     pub struct C(pub isize, isize);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider making the fields publicly accessible
+   |
+LL |     pub struct C(pub isize, pub isize);
+   |                  ~~~        +++
 
 error[E0603]: tuple struct constructor `C` is private
   --> $DIR/privacy5.rs:75:18
@@ -312,6 +392,10 @@ note: the tuple struct constructor `C` is defined here
    |
 LL |     pub struct C(pub isize, isize);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider making the fields publicly accessible
+   |
+LL |     pub struct C(pub isize, pub isize);
+   |                  ~~~        +++
 
 error[E0603]: tuple struct constructor `A` is private
   --> $DIR/privacy5.rs:83:17
@@ -327,6 +411,10 @@ note: the tuple struct constructor `A` is defined here
    |
 LL |     pub struct A(());
    |     ^^^^^^^^^^^^^^^^^
+help: consider making the field publicly accessible
+   |
+LL |     pub struct A(pub ());
+   |                  +++
 
 error[E0603]: tuple struct constructor `B` is private
   --> $DIR/privacy5.rs:84:17
@@ -342,6 +430,10 @@ note: the tuple struct constructor `B` is defined here
    |
 LL |     pub struct B(isize);
    |     ^^^^^^^^^^^^^^^^^^^^
+help: consider making the field publicly accessible
+   |
+LL |     pub struct B(pub isize);
+   |                  +++
 
 error[E0603]: tuple struct constructor `C` is private
   --> $DIR/privacy5.rs:85:17
@@ -357,6 +449,10 @@ note: the tuple struct constructor `C` is defined here
    |
 LL |     pub struct C(pub isize, isize);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider making the fields publicly accessible
+   |
+LL |     pub struct C(pub isize, pub isize);
+   |                  ~~~        +++
 
 error[E0603]: tuple struct constructor `A` is private
   --> $DIR/privacy5.rs:90:20

tests/ui/privacy/suggest-making-field-public.fixed

@@ -0,0 +1,15 @@
+// run-rustfix
+mod a {
+    pub struct A(pub String);
+}
+
+mod b {
+    use crate::a::A;
+    pub fn x() {
+        A("".into()); //~ ERROR cannot initialize a tuple struct which contains private fields
+    }
+}
+fn main() {
+    a::A("a".into()); //~ ERROR tuple struct constructor `A` is private
+    b::x();
+}

tests/ui/privacy/suggest-making-field-public.rs

@@ -0,0 +1,15 @@
+// run-rustfix
+mod a {
+    pub struct A(pub(self)String);
+}
+
+mod b {
+    use crate::a::A;
+    pub fn x() {
+        A("".into()); //~ ERROR cannot initialize a tuple struct which contains private fields
+    }
+}
+fn main() {
+    a::A("a".into()); //~ ERROR tuple struct constructor `A` is private
+    b::x();
+}

tests/ui/privacy/suggest-making-field-public.stderr

@@ -0,0 +1,39 @@
+error[E0603]: tuple struct constructor `A` is private
+  --> $DIR/suggest-making-field-public.rs:13:8
+   |
+LL |     pub struct A(pub(self)String);
+   |                  --------------- a constructor is private if any of the fields is private
+...
+LL |     a::A("a".into());
+   |        ^ private tuple struct constructor
+   |
+note: the tuple struct constructor `A` is defined here
+  --> $DIR/suggest-making-field-public.rs:3:5
+   |
+LL |     pub struct A(pub(self)String);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider making the field publicly accessible
+   |
+LL |     pub struct A(pub String);
+   |                  ~~~
+
+error[E0423]: cannot initialize a tuple struct which contains private fields
+  --> $DIR/suggest-making-field-public.rs:9:9
+   |
+LL |         A("".into());
+   |         ^
+   |
+note: constructor is not visible here due to private fields
+  --> $DIR/suggest-making-field-public.rs:3:18
+   |
+LL |     pub struct A(pub(self)String);
+   |                  ^^^^^^^^^^^^^^^ private field
+help: consider making the field publicly accessible
+   |
+LL |     pub struct A(pub String);
+   |                  ~~~
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0423, E0603.
+For more information about an error, try `rustc --explain E0423`.

tests/ui/resolve/issue-42944.rs

@@ -1,5 +1,5 @@
 mod foo {
-    pub struct Bx(());
+    pub struct Bx(pub(in crate::foo) ());
 }
 
 mod bar {

tests/ui/resolve/issue-42944.stderr

@@ -7,8 +7,8 @@ LL |         Bx(());
 note: tuple struct `foo::Bx` exists but is inaccessible
   --> $DIR/issue-42944.rs:2:5
    |
-LL |     pub struct Bx(());
+LL |     pub struct Bx(pub(in crate::foo) ());
-   |     ^^^^^^^^^^^^^^^^^^ not accessible
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not accessible
 
 error[E0423]: cannot initialize a tuple struct which contains private fields
   --> $DIR/issue-42944.rs:9:9
@@ -19,8 +19,12 @@ LL |         Bx(());
 note: constructor is not visible here due to private fields
   --> $DIR/issue-42944.rs:2:19
    |
-LL |     pub struct Bx(());
+LL |     pub struct Bx(pub(in crate::foo) ());
-   |                   ^^ private field
+   |                   ^^^^^^^^^^^^^^^^^^^^^ private field
+help: consider making the field publicly accessible
+   |
+LL |     pub struct Bx(pub ());
+   |                   ~~~
 
 error: aborting due to 2 previous errors
 

tests/ui/resolve/privacy-struct-ctor.stderr

@@ -53,6 +53,10 @@ note: the tuple struct constructor `Z` is defined here
    |
 LL |         pub(in m) struct Z(pub(in m::n) u8);
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider making the field publicly accessible
+   |
+LL |         pub(in m) struct Z(pub u8);
+   |                            ~~~
 
 error[E0603]: tuple struct constructor `S` is private
   --> $DIR/privacy-struct-ctor.rs:29:8
@@ -68,6 +72,10 @@ note: the tuple struct constructor `S` is defined here
    |
 LL |     pub struct S(u8);
    |     ^^^^^^^^^^^^^^^^^
+help: consider making the field publicly accessible
+   |
+LL |     pub struct S(pub u8);
+   |                  +++
 
 error[E0603]: tuple struct constructor `S` is private
   --> $DIR/privacy-struct-ctor.rs:31:19
@@ -83,6 +91,10 @@ note: the tuple struct constructor `S` is defined here
    |
 LL |     pub struct S(u8);
    |     ^^^^^^^^^^^^^^^^^
+help: consider making the field publicly accessible
+   |
+LL |     pub struct S(pub u8);
+   |                  +++
 
 error[E0603]: tuple struct constructor `Z` is private
   --> $DIR/privacy-struct-ctor.rs:35:11
@@ -98,6 +110,10 @@ note: the tuple struct constructor `Z` is defined here
    |
 LL |         pub(in m) struct Z(pub(in m::n) u8);
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider making the field publicly accessible
+   |
+LL |         pub(in m) struct Z(pub u8);
+   |                            ~~~
 
 error[E0603]: tuple struct constructor `S` is private
   --> $DIR/privacy-struct-ctor.rs:41:16