Check types of statics in MIR typeck

Author: matthewjasper

src/librustc_mir/borrow_check/type_check/mod.rs

@@ -309,6 +309,7 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
                 );
             }
         } else {
+            let tcx = self.tcx();
             if let ty::ConstKind::Unevaluated(def_id, substs, promoted) = constant.literal.val {
                 if let Some(promoted) = promoted {
                     let check_err = |verifier: &mut TypeVerifier<'a, 'b, 'tcx>,
@@ -358,10 +359,23 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
                         );
                     }
                 }
+            } else if let Some(static_def_id) = constant.check_static_ptr(tcx) {
+                let unnormalized_ty = tcx.type_of(static_def_id);
+                let locations = location.to_locations();
+                let normalized_ty = self.cx.normalize(unnormalized_ty, locations);
+                let literal_ty = constant.literal.ty.builtin_deref(true).unwrap().ty;
+
+                if let Err(terr) = self.cx.eq_types(
+                    normalized_ty,
+                    literal_ty,
+                    locations,
+                    ConstraintCategory::Boring,
+                ) {
+                    span_mirbug!(self, constant, "bad static type {:?} ({:?})", constant, terr);
+                }
             }
-            if let ty::FnDef(def_id, substs) = constant.literal.ty.kind {
-                let tcx = self.tcx();
 
+            if let ty::FnDef(def_id, substs) = constant.literal.ty.kind {
                 let instantiated_predicates = tcx.predicates_of(def_id).instantiate(tcx, substs);
                 self.cx.normalize_and_prove_instantiated_predicates(
                     instantiated_predicates,

src/test/ui/nll/issue-69114-static-mut-ty.rs

@@ -0,0 +1,30 @@
+// Check that borrowck ensures that `static mut` items have the expected type.
+
+static FOO: u8 = 42;
+static mut BAR: &'static u8 = &FOO;
+static mut BAR_ELIDED: &u8 = &FOO;
+
+fn main() {
+    unsafe {
+        println!("{} {}", BAR, BAR_ELIDED);
+        set_bar();
+        set_bar_elided();
+        println!("{} {}", BAR, BAR_ELIDED);
+    }
+}
+
+fn set_bar() {
+    let n = 42;
+    unsafe {
+        BAR = &n;
+        //~^ ERROR does not live long enough
+    }
+}
+
+fn set_bar_elided() {
+    let n = 42;
+    unsafe {
+        BAR_ELIDED = &n;
+        //~^ ERROR does not live long enough
+    }
+}

src/test/ui/nll/issue-69114-static-mut-ty.stderr

@@ -0,0 +1,27 @@
+error[E0597]: `n` does not live long enough
+  --> $DIR/issue-69114-static-mut-ty.rs:19:15
+   |
+LL |         BAR = &n;
+   |         ------^^
+   |         |     |
+   |         |     borrowed value does not live long enough
+   |         assignment requires that `n` is borrowed for `'static`
+...
+LL | }
+   | - `n` dropped here while still borrowed
+
+error[E0597]: `n` does not live long enough
+  --> $DIR/issue-69114-static-mut-ty.rs:27:22
+   |
+LL |         BAR_ELIDED = &n;
+   |         -------------^^
+   |         |            |
+   |         |            borrowed value does not live long enough
+   |         assignment requires that `n` is borrowed for `'static`
+...
+LL | }
+   | - `n` dropped here while still borrowed
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0597`.

src/test/ui/nll/issue-69114-static-ty.rs

@@ -0,0 +1,9 @@
+// Check that borrowck ensures that `static` items have the expected type.
+
+static FOO: &'static (dyn Fn(&'static u8) + Send + Sync) = &drop;
+
+fn main() {
+    let n = 42;
+    FOO(&n);
+    //~^ ERROR does not live long enough
+}

src/test/ui/nll/issue-69114-static-ty.stderr

@@ -0,0 +1,15 @@
+error[E0597]: `n` does not live long enough
+  --> $DIR/issue-69114-static-ty.rs:7:9
+   |
+LL |     FOO(&n);
+   |     ----^^-
+   |     |   |
+   |     |   borrowed value does not live long enough
+   |     argument requires that `n` is borrowed for `'static`
+LL |
+LL | }
+   | - `n` dropped here while still borrowed
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0597`.