diff --git a/src/librustc/ty/util.rs b/src/librustc/ty/util.rs
index d808387e269fd..67507f7b5d116 100644
--- a/src/librustc/ty/util.rs
+++ b/src/librustc/ty/util.rs
@@ -612,9 +612,14 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         })
     }
 
-    /// Returns `true` if the node pointed to by `def_id` is a static item, and its mutability.
-    pub fn is_static(&self, def_id: DefId) -> Option<hir::Mutability> {
-        self.static_mutability(def_id)
+    /// Returns `true` if the node pointed to by `def_id` is a `static` item.
+    pub fn is_static(&self, def_id: DefId) -> bool {
+        self.static_mutability(def_id).is_some()
+    }
+
+    /// Returns `true` if the node pointed to by `def_id` is a mutable `static` item.
+    pub fn is_mutable_static(&self, def_id: DefId) -> bool {
+        self.static_mutability(def_id) == Some(hir::MutMutable)
     }
 
     /// Expands the given impl trait type, stopping if the type is recursive.
diff --git a/src/librustc_codegen_llvm/common.rs b/src/librustc_codegen_llvm/common.rs
index 9554e54e4142a..b9fd9629e6ff1 100644
--- a/src/librustc_codegen_llvm/common.rs
+++ b/src/librustc_codegen_llvm/common.rs
@@ -322,7 +322,7 @@ impl ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
                         self.get_fn(fn_instance)
                     }
                     Some(AllocKind::Static(def_id)) => {
-                        assert!(self.tcx.is_static(def_id).is_some());
+                        assert!(self.tcx.is_static(def_id));
                         self.get_static(def_id)
                     }
                     None => bug!("missing allocation {:?}", ptr.alloc_id),
diff --git a/src/librustc_lint/builtin.rs b/src/librustc_lint/builtin.rs
index f289b0b48fbdf..5fde4331d4702 100644
--- a/src/librustc_lint/builtin.rs
+++ b/src/librustc_lint/builtin.rs
@@ -1171,8 +1171,7 @@ declare_lint_pass!(
 
 fn check_const(cx: &LateContext<'_, '_>, body_id: hir::BodyId) {
     let def_id = cx.tcx.hir().body_owner_def_id(body_id);
-    let is_static = cx.tcx.is_static(def_id).is_some();
-    let param_env = if is_static {
+    let param_env = if cx.tcx.is_static(def_id) {
         // Use the same param_env as `codegen_static_initializer`, to reuse the cache.
         ty::ParamEnv::reveal_all()
     } else {
diff --git a/src/librustc_mir/borrow_check/mod.rs b/src/librustc_mir/borrow_check/mod.rs
index 0b2c90b916045..43ed85d4ac541 100644
--- a/src/librustc_mir/borrow_check/mod.rs
+++ b/src/librustc_mir/borrow_check/mod.rs
@@ -2117,7 +2117,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
                     is_local_mutation_allowed,
                 }),
             Place::Base(PlaceBase::Static(box Static{ kind: StaticKind::Static(def_id), .. })) => {
-                if self.infcx.tcx.is_static(def_id) != Some(hir::Mutability::MutMutable) {
+                if !self.infcx.tcx.is_mutable_static(def_id) {
                     Err(place)
                 } else {
                     Ok(RootPlace {
diff --git a/src/librustc_mir/borrow_check/nll/type_check/mod.rs b/src/librustc_mir/borrow_check/nll/type_check/mod.rs
index d123f3e405936..ce8f1852551f2 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/mod.rs
@@ -1321,7 +1321,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
                         ..
                     }) = self.borrowck_context
                     {
-                        if tcx.is_static(*def_id).is_some() {
+                        if tcx.is_static(*def_id) {
                             ConstraintCategory::UseAsStatic
                         } else {
                             ConstraintCategory::UseAsConst
@@ -1626,7 +1626,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
                             ..
                         }) = self.borrowck_context
                         {
-                            if tcx.is_static(*def_id).is_some() {
+                            if tcx.is_static(*def_id) {
                                 ConstraintCategory::UseAsStatic
                             } else {
                                 ConstraintCategory::UseAsConst
diff --git a/src/librustc_mir/borrow_check/place_ext.rs b/src/librustc_mir/borrow_check/place_ext.rs
index 8269b7b95f490..913884a821837 100644
--- a/src/librustc_mir/borrow_check/place_ext.rs
+++ b/src/librustc_mir/borrow_check/place_ext.rs
@@ -52,7 +52,7 @@ impl<'tcx> PlaceExt<'tcx> for Place<'tcx> {
             Place::Base(PlaceBase::Static(box Static{ kind: StaticKind::Promoted(_), .. })) =>
                 false,
             Place::Base(PlaceBase::Static(box Static{ kind: StaticKind::Static(def_id), .. })) => {
-                tcx.is_static(*def_id) == Some(hir::Mutability::MutMutable)
+                tcx.is_mutable_static(*def_id)
             }
             Place::Projection(proj) => match proj.elem {
                 ProjectionElem::Field(..)
diff --git a/src/librustc_mir/borrow_check/places_conflict.rs b/src/librustc_mir/borrow_check/places_conflict.rs
index cebf05ad9b99d..1bf606109dc76 100644
--- a/src/librustc_mir/borrow_check/places_conflict.rs
+++ b/src/librustc_mir/borrow_check/places_conflict.rs
@@ -321,7 +321,7 @@ fn place_base_conflict<'a, 'gcx: 'tcx, 'tcx>(
                     if def_id_1 != def_id_2 {
                         debug!("place_element_conflict: DISJOINT-STATIC");
                         Overlap::Disjoint
-                    } else if tcx.is_static(*def_id_1) == Some(hir::Mutability::MutMutable) {
+                    } else if tcx.is_mutable_static(*def_id_1) {
                         // We ignore mutable statics - they can only be unsafe code.
                         debug!("place_element_conflict: IGNORE-STATIC-MUT");
                         Overlap::Disjoint
diff --git a/src/librustc_mir/const_eval.rs b/src/librustc_mir/const_eval.rs
index 09c50d4f81f49..b65f2ba2601e4 100644
--- a/src/librustc_mir/const_eval.rs
+++ b/src/librustc_mir/const_eval.rs
@@ -6,8 +6,8 @@ use std::borrow::{Borrow, Cow};
 use std::hash::Hash;
 use std::collections::hash_map::Entry;
 
-use rustc::hir::{self, def_id::DefId};
 use rustc::hir::def::Def;
+use rustc::hir::def_id::DefId;
 use rustc::mir::interpret::{ConstEvalErr, ErrorHandled};
 use rustc::mir;
 use rustc::ty::{self, TyCtxt, query::TyCtxtAt};
@@ -158,9 +158,8 @@ fn eval_body_using_ecx<'mir, 'tcx>(
     ecx.run()?;
 
     // Intern the result
-    let internally_mutable = !layout.ty.is_freeze(tcx, param_env, mir.span);
-    let is_static = tcx.is_static(cid.instance.def_id());
-    let mutability = if is_static == Some(hir::Mutability::MutMutable) || internally_mutable {
+    let mutability = if tcx.is_mutable_static(cid.instance.def_id()) ||
+                     !layout.ty.is_freeze(tcx, param_env, mir.span) {
         Mutability::Mutable
     } else {
         Mutability::Immutable
@@ -533,7 +532,7 @@ fn validate_and_turn_into_const<'a, 'tcx>(
         }
         // Now that we validated, turn this into a proper constant.
         let def_id = cid.instance.def.def_id();
-        if tcx.is_static(def_id).is_some() || cid.promoted.is_some() {
+        if tcx.is_static(def_id) || cid.promoted.is_some() {
             Ok(mplace_to_const(&ecx, mplace))
         } else {
             Ok(op_to_const(&ecx, mplace.into()))
@@ -628,7 +627,7 @@ pub fn const_eval_raw_provider<'a, 'tcx>(
     }).map_err(|error| {
         let err = error_to_const_error(&ecx, error);
         // errors in statics are always emitted as fatal errors
-        if tcx.is_static(def_id).is_some() {
+        if tcx.is_static(def_id) {
             // Ensure that if the above error was either `TooGeneric` or `Reported`
             // an error must be reported.
             let reported_err = tcx.sess.track_errors(|| {
diff --git a/src/librustc_mir/interpret/eval_context.rs b/src/librustc_mir/interpret/eval_context.rs
index 32f7ecd97b2ef..4ae8bfe854d78 100644
--- a/src/librustc_mir/interpret/eval_context.rs
+++ b/src/librustc_mir/interpret/eval_context.rs
@@ -634,7 +634,7 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> InterpretCx<'a, 'mir, 'tc
         &self,
         gid: GlobalId<'tcx>,
     ) -> EvalResult<'tcx, MPlaceTy<'tcx, M::PointerTag>> {
-        let param_env = if self.tcx.is_static(gid.instance.def_id()).is_some() {
+        let param_env = if self.tcx.is_static(gid.instance.def_id()) {
             ty::ParamEnv::reveal_all()
         } else {
             self.param_env
diff --git a/src/librustc_mir/interpret/memory.rs b/src/librustc_mir/interpret/memory.rs
index 117bd15399cde..9674822b47a3d 100644
--- a/src/librustc_mir/interpret/memory.rs
+++ b/src/librustc_mir/interpret/memory.rs
@@ -342,7 +342,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> Memory<'a, 'mir, 'tcx, M> {
         // full query anyway
         tcx.const_eval_raw(ty::ParamEnv::reveal_all().and(gid)).map_err(|err| {
             // no need to report anything, the const_eval call takes care of that for statics
-            assert!(tcx.is_static(def_id).is_some());
+            assert!(tcx.is_static(def_id));
             match err {
                 ErrorHandled::Reported => InterpError::ReferencedConstant.into(),
                 ErrorHandled::TooGeneric => InterpError::TooGeneric.into(),
diff --git a/src/librustc_mir/transform/check_unsafety.rs b/src/librustc_mir/transform/check_unsafety.rs
index c9cccb2b03ac4..87c02b7f01da3 100644
--- a/src/librustc_mir/transform/check_unsafety.rs
+++ b/src/librustc_mir/transform/check_unsafety.rs
@@ -306,7 +306,7 @@ impl<'a, 'tcx> Visitor<'tcx> for UnsafetyChecker<'a, 'tcx> {
             &Place::Base(
                 PlaceBase::Static(box Static { kind: StaticKind::Static(def_id), .. })
             ) => {
-                if self.tcx.is_static(def_id) == Some(hir::Mutability::MutMutable) {
+                if self.tcx.is_mutable_static(def_id) {
                     self.require_unsafe("use of mutable static",
                         "mutable statics can be mutated by multiple threads: aliasing violations \
                          or data races will cause undefined behavior",