Make THIR unsafe checker recognise thread_local statics

Author: matthewjasper

compiler/rustc_mir_build/src/check_unsafety.rs

@@ -379,7 +379,9 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> {
                 }
             }
             ExprKind::Deref { arg } => {
-                if let ExprKind::StaticRef { def_id, .. } = self.thir[arg].kind {
+                if let ExprKind::StaticRef { def_id, .. } | ExprKind::ThreadLocalRef(def_id) =
+                    self.thir[arg].kind
+                {
                     if self.tcx.is_mutable_static(def_id) {
                         self.requires_unsafe(expr.span, UseOfMutableStatic);
                     } else if self.tcx.is_foreign_item(def_id) {

tests/ui/thread-local/thread-local-static.stderr renamed to tests/ui/thread-local/thread-local-static.mir.stderr

@@ -1,5 +1,5 @@
 error[E0658]: mutable references are not allowed in constant functions
-  --> $DIR/thread-local-static.rs:7:12
+  --> $DIR/thread-local-static.rs:10:12
    |
 LL | const fn g(x: &mut [u32; 8]) {
    |            ^
@@ -8,21 +8,21 @@ LL | const fn g(x: &mut [u32; 8]) {
    = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
 
 error[E0625]: thread-local statics cannot be accessed at compile-time
-  --> $DIR/thread-local-static.rs:9:28
+  --> $DIR/thread-local-static.rs:12:28
    |
 LL |     std::mem::swap(x, &mut STATIC_VAR_2)
    |                            ^^^^^^^^^^^^
 
 error[E0013]: constant functions cannot refer to statics
-  --> $DIR/thread-local-static.rs:9:28
+  --> $DIR/thread-local-static.rs:12:28
    |
 LL |     std::mem::swap(x, &mut STATIC_VAR_2)
    |                            ^^^^^^^^^^^^
    |
    = help: consider extracting the value of the `static` to a `const`, and referring to that
 
 error[E0658]: mutable references are not allowed in constant functions
-  --> $DIR/thread-local-static.rs:9:23
+  --> $DIR/thread-local-static.rs:12:23
    |
 LL |     std::mem::swap(x, &mut STATIC_VAR_2)
    |                       ^^^^^^^^^^^^^^^^^
@@ -31,7 +31,7 @@ LL |     std::mem::swap(x, &mut STATIC_VAR_2)
    = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
 
 error[E0133]: use of mutable static is unsafe and requires unsafe function or block
-  --> $DIR/thread-local-static.rs:9:23
+  --> $DIR/thread-local-static.rs:12:23
    |
 LL |     std::mem::swap(x, &mut STATIC_VAR_2)
    |                       ^^^^^^^^^^^^^^^^^ use of mutable static

tests/ui/thread-local/thread-local-static.rs

@@ -1,5 +1,8 @@
 // edition:2018
 
+// revisions: mir thir
+// [thir]compile-flags: -Zthir-unsafeck
+
 #![feature(thread_local)]
 #![feature(const_swap)]
 #[thread_local]

tests/ui/thread-local/thread-local-static.thir.stderr

@@ -0,0 +1,44 @@
+error[E0133]: use of mutable static is unsafe and requires unsafe function or block
+  --> $DIR/thread-local-static.rs:12:28
+   |
+LL |     std::mem::swap(x, &mut STATIC_VAR_2)
+   |                            ^^^^^^^^^^^^ use of mutable static
+   |
+   = note: mutable statics can be mutated by multiple threads: aliasing violations or data races will cause undefined behavior
+
+error[E0658]: mutable references are not allowed in constant functions
+  --> $DIR/thread-local-static.rs:10:12
+   |
+LL | const fn g(x: &mut [u32; 8]) {
+   |            ^
+   |
+   = note: see issue #57349 <https://github.com/rust-lang/rust/issues/57349> for more information
+   = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
+
+error[E0625]: thread-local statics cannot be accessed at compile-time
+  --> $DIR/thread-local-static.rs:12:28
+   |
+LL |     std::mem::swap(x, &mut STATIC_VAR_2)
+   |                            ^^^^^^^^^^^^
+
+error[E0013]: constant functions cannot refer to statics
+  --> $DIR/thread-local-static.rs:12:28
+   |
+LL |     std::mem::swap(x, &mut STATIC_VAR_2)
+   |                            ^^^^^^^^^^^^
+   |
+   = help: consider extracting the value of the `static` to a `const`, and referring to that
+
+error[E0658]: mutable references are not allowed in constant functions
+  --> $DIR/thread-local-static.rs:12:23
+   |
+LL |     std::mem::swap(x, &mut STATIC_VAR_2)
+   |                       ^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #57349 <https://github.com/rust-lang/rust/issues/57349> for more information
+   = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
+
+error: aborting due to 5 previous errors
+
+Some errors have detailed explanations: E0013, E0133, E0625, E0658.
+For more information about an error, try `rustc --explain E0013`.