Auto merge of #91320 - matthiaskrgr:rollup-r209seq, r=matthiaskrgr

Rollup of 3 pull requests

Successful merges:

 - #91251 (Perform Sync check on static items in wf-check instead of during const checks)
 - #91308 (Fix ICE when lowering `trait A where for<'a> Self: 'a`)
 - #91319 (Change output path to {{build-base}} for rustdoc scrape_examples ui test)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_const_eval/src/transform/check_consts/check.rs

@@ -1,8 +1,8 @@
 //! The `Visitor` responsible for actually checking a `mir::Body` for invalid operations.
 
 use rustc_errors::{Applicability, Diagnostic, ErrorReported};
+use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
-use rustc_hir::{self as hir, HirId, LangItem};
 use rustc_index::bit_set::BitSet;
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_infer::traits::{ImplSource, Obligation, ObligationCause};
@@ -14,8 +14,7 @@ use rustc_middle::ty::{self, adjustment::PointerCast, Instance, InstanceDef, Ty,
 use rustc_middle::ty::{Binder, TraitPredicate, TraitRef};
 use rustc_mir_dataflow::{self, Analysis};
 use rustc_span::{sym, Span, Symbol};
-use rustc_trait_selection::traits::error_reporting::InferCtxtExt;
-use rustc_trait_selection::traits::{self, SelectionContext, TraitEngine};
+use rustc_trait_selection::traits::SelectionContext;
 
 use std::mem;
 use std::ops::Deref;
@@ -255,16 +254,6 @@ impl Checker<'mir, 'tcx> {
             self.visit_body(&body);
         }
 
-        // Ensure that the end result is `Sync` in a non-thread local `static`.
-        let should_check_for_sync = self.const_kind()
-            == hir::ConstContext::Static(hir::Mutability::Not)
-            && !tcx.is_thread_local_static(def_id.to_def_id());
-
-        if should_check_for_sync {
-            let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
-            check_return_ty_is_sync(tcx, &body, hir_id);
-        }
-
         // If we got through const-checking without emitting any "primary" errors, emit any
         // "secondary" errors if they occurred.
         let secondary_errors = mem::take(&mut self.secondary_errors);
@@ -1054,20 +1043,6 @@ impl Visitor<'tcx> for Checker<'mir, 'tcx> {
     }
 }
 
-fn check_return_ty_is_sync(tcx: TyCtxt<'tcx>, body: &Body<'tcx>, hir_id: HirId) {
-    let ty = body.return_ty();
-    tcx.infer_ctxt().enter(|infcx| {
-        let cause = traits::ObligationCause::new(body.span, hir_id, traits::SharedStatic);
-        let mut fulfillment_cx = traits::FulfillmentContext::new();
-        let sync_def_id = tcx.require_lang_item(LangItem::Sync, Some(body.span));
-        fulfillment_cx.register_bound(&infcx, ty::ParamEnv::empty(), ty, sync_def_id, cause);
-        let errors = fulfillment_cx.select_all_or_error(&infcx);
-        if !errors.is_empty() {
-            infcx.report_fulfillment_errors(&errors, None, false);
-        }
-    });
-}
-
 fn place_as_reborrow(
     tcx: TyCtxt<'tcx>,
     body: &Body<'tcx>,

compiler/rustc_typeck/src/check/wfcheck.rs

@@ -1060,6 +1060,20 @@ fn check_item_type(tcx: TyCtxt<'_>, item_id: LocalDefId, ty_span: Span, allow_fo
             );
         }
 
+        // Ensure that the end result is `Sync` in a non-thread local `static`.
+        let should_check_for_sync = tcx.static_mutability(item_id.to_def_id())
+            == Some(hir::Mutability::Not)
+            && !tcx.is_foreign_item(item_id.to_def_id())
+            && !tcx.is_thread_local_static(item_id.to_def_id());
+
+        if should_check_for_sync {
+            fcx.register_bound(
+                item_ty,
+                tcx.require_lang_item(LangItem::Sync, Some(ty_span)),
+                traits::ObligationCause::new(ty_span, fcx.body_id, traits::SharedStatic),
+            );
+        }
+
         // No implied bounds in a const, etc.
         FxHashSet::default()
     });

compiler/rustc_typeck/src/collect.rs

@@ -666,7 +666,7 @@ impl ItemCtxt<'tcx> {
                 Some(assoc_name) => self.bound_defines_assoc_item(b, assoc_name),
                 None => true,
             })
-            .flat_map(|b| predicates_from_bound(self, ty, b));
+            .flat_map(|b| predicates_from_bound(self, ty, b, ty::List::empty()));
 
         let param_def_id = self.tcx.hir().local_def_id(param_id).to_def_id();
         let from_where_clauses = ast_generics
@@ -685,15 +685,17 @@ impl ItemCtxt<'tcx> {
                 } else {
                     None
                 };
+                let bvars = self.tcx.late_bound_vars(bp.bounded_ty.hir_id);
+
                 bp.bounds
                     .iter()
                     .filter(|b| match assoc_name {
                         Some(assoc_name) => self.bound_defines_assoc_item(b, assoc_name),
                         None => true,
                     })
-                    .filter_map(move |b| bt.map(|bt| (bt, b)))
+                    .filter_map(move |b| bt.map(|bt| (bt, b, bvars)))
             })
-            .flat_map(|(bt, b)| predicates_from_bound(self, bt, b));
+            .flat_map(|(bt, b, bvars)| predicates_from_bound(self, bt, b, bvars));
 
         from_ty_params.chain(from_where_clauses).collect()
     }
@@ -2433,14 +2435,10 @@ fn predicates_from_bound<'tcx>(
     astconv: &dyn AstConv<'tcx>,
     param_ty: Ty<'tcx>,
     bound: &'tcx hir::GenericBound<'tcx>,
+    bound_vars: &'tcx ty::List<ty::BoundVariableKind>,
 ) -> Vec<(ty::Predicate<'tcx>, Span)> {
     let mut bounds = Bounds::default();
-    astconv.add_bounds(
-        param_ty,
-        std::array::IntoIter::new([bound]),
-        &mut bounds,
-        ty::List::empty(),
-    );
+    astconv.add_bounds(param_ty, [bound].into_iter(), &mut bounds, bound_vars);
     bounds.predicates(astconv.tcx(), param_ty)
 }
 

src/test/rustdoc-ui/scrape-examples-ice.rs

@@ -1,4 +1,4 @@
-// compile-flags: -Z unstable-options --scrape-examples-output-path t.calls --scrape-examples-target-crate foobar
+// compile-flags: -Z unstable-options --scrape-examples-output-path {{build-base}}/t.calls --scrape-examples-target-crate foobar
 // check-pass
 #![no_std]
 use core as _;

src/test/ui/consts/const-cast-different-types.rs

@@ -1,6 +1,6 @@
-static a: &'static str = "foo";
-static b: *const u8 = a as *const u8; //~ ERROR casting
-static c: *const u8 = &a as *const u8; //~ ERROR casting
+const a: &str = "foo";
+const b: *const u8 = a as *const u8; //~ ERROR casting
+const c: *const u8 = &a as *const u8; //~ ERROR casting
 
 fn main() {
 }

src/test/ui/consts/const-cast-different-types.stderr

@@ -1,14 +1,14 @@
 error[E0606]: casting `&'static str` as `*const u8` is invalid
-  --> $DIR/const-cast-different-types.rs:2:23
+  --> $DIR/const-cast-different-types.rs:2:22
    |
-LL | static b: *const u8 = a as *const u8;
-   |                       ^^^^^^^^^^^^^^
+LL | const b: *const u8 = a as *const u8;
+   |                      ^^^^^^^^^^^^^^
 
 error[E0606]: casting `&&'static str` as `*const u8` is invalid
-  --> $DIR/const-cast-different-types.rs:3:23
+  --> $DIR/const-cast-different-types.rs:3:22
    |
-LL | static c: *const u8 = &a as *const u8;
-   |                       ^^^^^^^^^^^^^^^
+LL | const c: *const u8 = &a as *const u8;
+   |                      ^^^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 

src/test/ui/consts/const-cast-wrong-type.rs

@@ -1,5 +1,5 @@
-static a: [u8; 3] = ['h' as u8, 'i' as u8, 0 as u8];
-static b: *const i8 = &a as *const i8; //~ ERROR mismatched types
+const a: [u8; 3] = ['h' as u8, 'i' as u8, 0 as u8];
+const b: *const i8 = &a as *const i8; //~ ERROR mismatched types
 
 fn main() {
 }

src/test/ui/consts/const-cast-wrong-type.stderr

@@ -1,8 +1,8 @@
 error[E0308]: mismatched types
-  --> $DIR/const-cast-wrong-type.rs:2:23
+  --> $DIR/const-cast-wrong-type.rs:2:22
    |
-LL | static b: *const i8 = &a as *const i8;
-   |                       ^^^^^^^^^^^^^^^ expected `u8`, found `i8`
+LL | const b: *const i8 = &a as *const i8;
+   |                      ^^^^^^^^^^^^^^^ expected `u8`, found `i8`
 
 error: aborting due to previous error
 

src/test/ui/higher-rank-trait-bounds/issue-88586-hr-self-outlives-in-trait-def.rs

@@ -0,0 +1,11 @@
+// Regression test for #88586: a higher-ranked outlives bound on Self in a trait
+// definition caused an ICE when debug_assertions were enabled.
+//
+// FIXME: The error output in the absence of the ICE is unhelpful; this should be improved.
+
+trait A where for<'a> Self: 'a
+//~^ ERROR the parameter type `Self` may not live long enough
+{
+}
+
+fn main() {}

src/test/ui/higher-rank-trait-bounds/issue-88586-hr-self-outlives-in-trait-def.stderr

@@ -0,0 +1,19 @@
+error[E0311]: the parameter type `Self` may not live long enough
+  --> $DIR/issue-88586-hr-self-outlives-in-trait-def.rs:6:1
+   |
+LL | / trait A where for<'a> Self: 'a
+LL | |
+LL | | {
+LL | | }
+   | |_^
+   |
+   = help: consider adding an explicit lifetime bound `Self: 'a`...
+   = note: ...so that the type `Self` will meet its required lifetime bounds...
+note: ...that is required by this bound
+  --> $DIR/issue-88586-hr-self-outlives-in-trait-def.rs:6:29
+   |
+LL | trait A where for<'a> Self: 'a
+   |                             ^^
+
+error: aborting due to previous error
+

src/test/ui/impl-trait/issues/issue-86201.rs

@@ -2,9 +2,9 @@
 #![feature(type_alias_impl_trait)]
 
 type FunType = impl Fn<()>;
-//~^ could not find defining uses
+//~^ ERROR could not find defining uses
 static STATIC_FN: FunType = some_fn;
-//~^ mismatched types
+//~^ ERROR mismatched types
 
 fn some_fn() {}
 

src/test/ui/issues/issue-16538.mir.stderr

@@ -1,27 +1,26 @@
 error[E0015]: calls in statics are limited to constant functions, tuple structs and tuple variants
-  --> $DIR/issue-16538.rs:14:27
+  --> $DIR/issue-16538.rs:15:23
    |
-LL | static foo: *const Y::X = Y::foo(Y::x as *const Y::X);
-   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | static foo: &Y::X = &*Y::foo(Y::x as *const Y::X);
+   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0277]: `*const usize` cannot be shared between threads safely
-  --> $DIR/issue-16538.rs:14:1
+error[E0133]: use of extern static is unsafe and requires unsafe function or block
+  --> $DIR/issue-16538.rs:15:30
    |
-LL | static foo: *const Y::X = Y::foo(Y::x as *const Y::X);
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `*const usize` cannot be shared between threads safely
+LL | static foo: &Y::X = &*Y::foo(Y::x as *const Y::X);
+   |                              ^^^^ use of extern static
    |
-   = help: the trait `Sync` is not implemented for `*const usize`
-   = note: shared static variables must have a type that implements `Sync`
+   = note: extern statics are not controlled by the Rust type system: invalid data, aliasing violations or data races will cause undefined behavior
 
-error[E0133]: use of extern static is unsafe and requires unsafe function or block
-  --> $DIR/issue-16538.rs:14:34
+error[E0133]: dereference of raw pointer is unsafe and requires unsafe function or block
+  --> $DIR/issue-16538.rs:15:21
    |
-LL | static foo: *const Y::X = Y::foo(Y::x as *const Y::X);
-   |                                  ^^^^ use of extern static
+LL | static foo: &Y::X = &*Y::foo(Y::x as *const Y::X);
+   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ dereference of raw pointer
    |
-   = note: extern statics are not controlled by the Rust type system: invalid data, aliasing violations or data races will cause undefined behavior
+   = note: raw pointers may be null, dangling or unaligned; they can violate aliasing rules and cause data races: all of these are undefined behavior
 
 error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0015, E0133, E0277.
+Some errors have detailed explanations: E0015, E0133.
 For more information about an error, try `rustc --explain E0015`.

src/test/ui/issues/issue-16538.rs

@@ -1,6 +1,7 @@
 // revisions: mir thir
 // [thir]compile-flags: -Z thir-unsafeck
 
+#![feature(const_raw_ptr_deref)]
 mod Y {
     pub type X = usize;
     extern "C" {
@@ -11,8 +12,8 @@ mod Y {
     }
 }
 
-static foo: *const Y::X = Y::foo(Y::x as *const Y::X);
-//~^ ERROR `*const usize` cannot be shared between threads safely [E0277]
+static foo: &Y::X = &*Y::foo(Y::x as *const Y::X);
+//~^ ERROR dereference of raw pointer
 //~| ERROR E0015
 //~| ERROR use of extern static is unsafe and requires
 

src/test/ui/issues/issue-16538.thir.stderr

@@ -1,27 +1,26 @@
+error[E0133]: dereference of raw pointer is unsafe and requires unsafe function or block
+  --> $DIR/issue-16538.rs:15:22
+   |
+LL | static foo: &Y::X = &*Y::foo(Y::x as *const Y::X);
+   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ dereference of raw pointer
+   |
+   = note: raw pointers may be null, dangling or unaligned; they can violate aliasing rules and cause data races: all of these are undefined behavior
+
 error[E0133]: use of extern static is unsafe and requires unsafe function or block
-  --> $DIR/issue-16538.rs:14:34
+  --> $DIR/issue-16538.rs:15:30
    |
-LL | static foo: *const Y::X = Y::foo(Y::x as *const Y::X);
-   |                                  ^^^^ use of extern static
+LL | static foo: &Y::X = &*Y::foo(Y::x as *const Y::X);
+   |                              ^^^^ use of extern static
    |
    = note: extern statics are not controlled by the Rust type system: invalid data, aliasing violations or data races will cause undefined behavior
 
 error[E0015]: calls in statics are limited to constant functions, tuple structs and tuple variants
-  --> $DIR/issue-16538.rs:14:27
-   |
-LL | static foo: *const Y::X = Y::foo(Y::x as *const Y::X);
-   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error[E0277]: `*const usize` cannot be shared between threads safely
-  --> $DIR/issue-16538.rs:14:1
-   |
-LL | static foo: *const Y::X = Y::foo(Y::x as *const Y::X);
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `*const usize` cannot be shared between threads safely
+  --> $DIR/issue-16538.rs:15:23
    |
-   = help: the trait `Sync` is not implemented for `*const usize`
-   = note: shared static variables must have a type that implements `Sync`
+LL | static foo: &Y::X = &*Y::foo(Y::x as *const Y::X);
+   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0015, E0133, E0277.
+Some errors have detailed explanations: E0015, E0133.
 For more information about an error, try `rustc --explain E0015`.

src/test/ui/issues/issue-17718-static-sync.stderr

@@ -1,8 +1,8 @@
 error[E0277]: `Foo` cannot be shared between threads safely
-  --> $DIR/issue-17718-static-sync.rs:9:1
+  --> $DIR/issue-17718-static-sync.rs:9:13
    |
 LL | static BAR: Foo = Foo;
-   | ^^^^^^^^^^^^^^^^^^^^^^ `Foo` cannot be shared between threads safely
+   |             ^^^ `Foo` cannot be shared between threads safely
    |
    = help: the trait `Sync` is not implemented for `Foo`
    = note: shared static variables must have a type that implements `Sync`

src/test/ui/issues/issue-24446.rs

@@ -1,6 +1,7 @@
 fn main() {
     static foo: dyn Fn() -> u32 = || -> u32 {
         //~^ ERROR the size for values of type
+        //~| ERROR cannot be shared between threads safely
         0
     };
 }

src/test/ui/issues/issue-24446.stderr

@@ -6,6 +6,15 @@ LL |     static foo: dyn Fn() -> u32 = || -> u32 {
    |
    = help: the trait `Sized` is not implemented for `(dyn Fn() -> u32 + 'static)`
 
-error: aborting due to previous error
+error[E0277]: `(dyn Fn() -> u32 + 'static)` cannot be shared between threads safely
+  --> $DIR/issue-24446.rs:2:17
+   |
+LL |     static foo: dyn Fn() -> u32 = || -> u32 {
+   |                 ^^^^^^^^^^^^^^^ `(dyn Fn() -> u32 + 'static)` cannot be shared between threads safely
+   |
+   = help: the trait `Sync` is not implemented for `(dyn Fn() -> u32 + 'static)`
+   = note: shared static variables must have a type that implements `Sync`
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0277`.

src/test/ui/issues/issue-5216.rs

@@ -1,10 +1,10 @@
 fn f() { }
-struct S(Box<dyn FnMut()>);
+struct S(Box<dyn FnMut() + Sync>);
 pub static C: S = S(f); //~ ERROR mismatched types
 
 
 fn g() { }
-type T = Box<dyn FnMut()>;
+type T = Box<dyn FnMut() + Sync>;
 pub static D: T = g; //~ ERROR mismatched types
 
 fn main() {}

src/test/ui/issues/issue-5216.stderr

@@ -4,7 +4,7 @@ error[E0308]: mismatched types
 LL | pub static C: S = S(f);
    |                     ^ expected struct `Box`, found fn item
    |
-   = note: expected struct `Box<(dyn FnMut() + 'static)>`
+   = note: expected struct `Box<(dyn FnMut() + Sync + 'static)>`
              found fn item `fn() {f}`
 
 error[E0308]: mismatched types
@@ -13,7 +13,7 @@ error[E0308]: mismatched types
 LL | pub static D: T = g;
    |                   ^ expected struct `Box`, found fn item
    |
-   = note: expected struct `Box<(dyn FnMut() + 'static)>`
+   = note: expected struct `Box<(dyn FnMut() + Sync + 'static)>`
              found fn item `fn() {g}`
 
 error: aborting due to 2 previous errors