Auto merge of #76499 - guswynn:priv_des, r=petrochenkov

Give better diagnostic when using a private tuple struct constructor

Fixes #75907

Some notes:
1. This required some deep changes, including removing a Copy impl for PatKind. If some tests fail, I would still appreciate review on the overall approach
2. this only works with basic patterns (no wildcards for example), and fails if there is any problems getting the visibility of the fields (i am not sure what the failure that can happen in resolve_visibility_speculative, but we check the length of our fields in both cases against each other, so if anything goes wrong, we fall back to the worse error. This could be extended to more patterns
3. this does not yet deal with #75906, but I believe it will be similar
4. let me know if you want more tests
5. doesn't yet at the suggestion that `@yoshuawuyts` suggested at the end of their issue, but that could be added relatively easily (i believe)

compiler/rustc_resolve/src/late.rs

@@ -188,7 +188,7 @@ crate enum PathSource<'a> {
     // Paths in struct expressions and patterns `Path { .. }`.
     Struct,
     // Paths in tuple struct patterns `Path(..)`.
-    TupleStruct(Span),
+    TupleStruct(Span, &'a [Span]),
     // `m::A::B` in `<T as m::A>::B::C`.
     TraitItem(Namespace),
 }
@@ -197,7 +197,7 @@ impl<'a> PathSource<'a> {
     fn namespace(self) -> Namespace {
         match self {
             PathSource::Type | PathSource::Trait(_) | PathSource::Struct => TypeNS,
-            PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct(_) => ValueNS,
+            PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct(..) => ValueNS,
             PathSource::TraitItem(ns) => ns,
         }
     }
@@ -208,7 +208,7 @@ impl<'a> PathSource<'a> {
             | PathSource::Expr(..)
             | PathSource::Pat
             | PathSource::Struct
-            | PathSource::TupleStruct(_) => true,
+            | PathSource::TupleStruct(..) => true,
             PathSource::Trait(_) | PathSource::TraitItem(..) => false,
         }
     }
@@ -219,7 +219,7 @@ impl<'a> PathSource<'a> {
             PathSource::Trait(_) => "trait",
             PathSource::Pat => "unit struct, unit variant or constant",
             PathSource::Struct => "struct, variant or union type",
-            PathSource::TupleStruct(_) => "tuple struct or tuple variant",
+            PathSource::TupleStruct(..) => "tuple struct or tuple variant",
             PathSource::TraitItem(ns) => match ns {
                 TypeNS => "associated type",
                 ValueNS => "method or associated constant",
@@ -305,7 +305,7 @@ impl<'a> PathSource<'a> {
                 | Res::SelfCtor(..) => true,
                 _ => false,
             },
-            PathSource::TupleStruct(_) => match res {
+            PathSource::TupleStruct(..) => match res {
                 Res::Def(DefKind::Ctor(_, CtorKind::Fn), _) | Res::SelfCtor(..) => true,
                 _ => false,
             },
@@ -340,8 +340,8 @@ impl<'a> PathSource<'a> {
             (PathSource::Struct, false) => error_code!(E0422),
             (PathSource::Expr(..), true) => error_code!(E0423),
             (PathSource::Expr(..), false) => error_code!(E0425),
-            (PathSource::Pat | PathSource::TupleStruct(_), true) => error_code!(E0532),
-            (PathSource::Pat | PathSource::TupleStruct(_), false) => error_code!(E0531),
+            (PathSource::Pat | PathSource::TupleStruct(..), true) => error_code!(E0532),
+            (PathSource::Pat | PathSource::TupleStruct(..), false) => error_code!(E0531),
             (PathSource::TraitItem(..), true) => error_code!(E0575),
             (PathSource::TraitItem(..), false) => error_code!(E0576),
         }
@@ -411,7 +411,7 @@ struct LateResolutionVisitor<'a, 'b, 'ast> {
 }
 
 /// Walks the whole crate in DFS order, visiting each item, resolving names as it goes.
-impl<'a, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
+impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
     fn visit_item(&mut self, item: &'ast Item) {
         let prev = replace(&mut self.diagnostic_metadata.current_item, Some(item));
         // Always report errors in items we just entered.
@@ -659,7 +659,7 @@ impl<'a, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
     }
 }
 
-impl<'a, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
+impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
     fn new(resolver: &'b mut Resolver<'a>) -> LateResolutionVisitor<'a, 'b, 'ast> {
         // During late resolution we only track the module component of the parent scope,
         // although it may be useful to track other components as well for diagnostics.
@@ -1539,8 +1539,16 @@ impl<'a, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                         .unwrap_or_else(|| self.fresh_binding(ident, pat.id, pat_src, bindings));
                     self.r.record_partial_res(pat.id, PartialRes::new(res));
                 }
-                PatKind::TupleStruct(ref path, ..) => {
-                    self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct(pat.span));
+                PatKind::TupleStruct(ref path, ref sub_patterns) => {
+                    self.smart_resolve_path(
+                        pat.id,
+                        None,
+                        path,
+                        PathSource::TupleStruct(
+                            pat.span,
+                            self.r.arenas.alloc_pattern_spans(sub_patterns.iter().map(|p| p.span)),
+                        ),
+                    );
                 }
                 PatKind::Path(ref qself, ref path) => {
                     self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);