diff --git a/.travis.yml b/.travis.yml
index 5f4724a89e..d42ef2287a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -36,6 +36,9 @@ script:
 notifications:
   email:
     on_success: never
+branches:
+  only:
+  - master
 env:
   global:
   - RUST_TEST_NOCAPTURE=1
diff --git a/miri/bin/miri.rs b/miri/bin/miri.rs
index 337a723a40..9b8790379d 100644
--- a/miri/bin/miri.rs
+++ b/miri/bin/miri.rs
@@ -131,7 +131,7 @@ fn after_analysis<'a, 'tcx>(state: &mut CompileState<'a, 'tcx>) {
         );
     } else if let Some((entry_node_id, _)) = *state.session.entry_fn.borrow() {
         let entry_def_id = tcx.hir.local_def_id(entry_node_id);
-        let start_wrapper = tcx.lang_items.start_fn().and_then(|start_fn| {
+        let start_wrapper = tcx.lang_items().start_fn().and_then(|start_fn| {
             if tcx.is_mir_available(start_fn) {
                 Some(start_fn)
             } else {
diff --git a/miri/fn_call.rs b/miri/fn_call.rs
index a74a53fa75..d64b254e7e 100644
--- a/miri/fn_call.rs
+++ b/miri/fn_call.rs
@@ -96,11 +96,11 @@ impl<'a, 'tcx> EvalContextExt<'tcx> for EvalContext<'a, 'tcx, super::Evaluator>
         dest_ty: Ty<'tcx>,
         dest_block: mir::BasicBlock,
     ) -> EvalResult<'tcx> {
-        let name = self.tcx.item_name(def_id);
         let attrs = self.tcx.get_attrs(def_id);
-        let link_name = attr::first_attr_value_str_by_name(&attrs, "link_name")
-            .unwrap_or(name)
-            .as_str();
+        let link_name = match attr::first_attr_value_str_by_name(&attrs, "link_name") {
+            Some(name) => name.as_str(),
+            None => self.tcx.item_name(def_id),
+        };
 
         match &link_name[..] {
             "malloc" => {
@@ -477,28 +477,26 @@ impl<'a, 'tcx> EvalContextExt<'tcx> for EvalContext<'a, 'tcx, super::Evaluator>
 
     /// Get an instance for a path.
     fn resolve_path(&self, path: &[&str]) -> EvalResult<'tcx, ty::Instance<'tcx>> {
-        let cstore = &self.tcx.sess.cstore;
-
-        let crates = cstore.crates();
-        crates
+        self.tcx
+            .crates()
             .iter()
-            .find(|&&krate| cstore.crate_name(krate) == path[0])
+            .find(|&&krate| self.tcx.original_crate_name(krate) == path[0])
             .and_then(|krate| {
                 let krate = DefId {
                     krate: *krate,
                     index: CRATE_DEF_INDEX,
                 };
-                let mut items = cstore.item_children(krate, self.tcx.sess);
+                let mut items = self.tcx.item_children(krate);
                 let mut path_it = path.iter().skip(1).peekable();
 
                 while let Some(segment) = path_it.next() {
-                    for item in &mem::replace(&mut items, vec![]) {
+                    for item in mem::replace(&mut items, Default::default()).iter() {
                         if item.ident.name == *segment {
                             if path_it.peek().is_none() {
                                 return Some(ty::Instance::mono(self.tcx, item.def.def_id()));
                             }
 
-                            items = cstore.item_children(item.def.def_id(), self.tcx.sess);
+                            items = self.tcx.item_children(item.def.def_id());
                             break;
                         }
                     }
diff --git a/miri/intrinsic.rs b/miri/intrinsic.rs
index 693a478c2d..bcff3b4aa9 100644
--- a/miri/intrinsic.rs
+++ b/miri/intrinsic.rs
@@ -32,7 +32,7 @@ impl<'a, 'tcx> EvalContextExt<'tcx> for EvalContext<'a, 'tcx, super::Evaluator>
     ) -> EvalResult<'tcx> {
         let substs = instance.substs;
 
-        let intrinsic_name = &self.tcx.item_name(instance.def_id()).as_str()[..];
+        let intrinsic_name = &self.tcx.item_name(instance.def_id())[..];
         match intrinsic_name {
             "align_offset" => {
                 // FIXME: return a real value in case the target allocation has an
diff --git a/rustc_tests/src/main.rs b/rustc_tests/src/main.rs
index ea699833f6..d1f2f07aaa 100644
--- a/rustc_tests/src/main.rs
+++ b/rustc_tests/src/main.rs
@@ -100,7 +100,7 @@ fn after_analysis<'a, 'tcx>(state: &mut CompileState<'a, 'tcx>) {
         state.hir_crate.unwrap().visit_all_item_likes(&mut Visitor(limits, tcx, state));
     } else if let Some((entry_node_id, _)) = *state.session.entry_fn.borrow() {
         let entry_def_id = tcx.hir.local_def_id(entry_node_id);
-        let start_wrapper = tcx.lang_items.start_fn().and_then(|start_fn|
+        let start_wrapper = tcx.lang_items().start_fn().and_then(|start_fn|
                                 if tcx.is_mir_available(start_fn) { Some(start_fn) } else { None });
         miri::eval_main(tcx, entry_def_id, start_wrapper, limits);
 
diff --git a/src/librustc_mir/interpret/eval_context.rs b/src/librustc_mir/interpret/eval_context.rs
index bc227fcc39..bd7a42cca1 100644
--- a/src/librustc_mir/interpret/eval_context.rs
+++ b/src/librustc_mir/interpret/eval_context.rs
@@ -508,8 +508,7 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
             stmt: 0,
         });
 
-        let cur_frame = self.cur_frame();
-        self.memory.set_cur_frame(cur_frame);
+        self.memory.cur_frame = self.cur_frame();
 
         if self.stack.len() > self.stack_limit {
             err!(StackFrameLimitReached)
@@ -520,14 +519,13 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
 
     pub(super) fn pop_stack_frame(&mut self) -> EvalResult<'tcx> {
         ::log_settings::settings().indentation -= 1;
-        self.memory.locks_lifetime_ended(None);
+        self.end_region(None)?;
         let frame = self.stack.pop().expect(
             "tried to pop a stack frame, but there were none",
         );
         if !self.stack.is_empty() {
-            // TODO: IS this the correct time to start considering these accesses as originating from the returned-to stack frame?
-            let cur_frame = self.cur_frame();
-            self.memory.set_cur_frame(cur_frame);
+            // TODO: Is this the correct time to start considering these accesses as originating from the returned-to stack frame?
+            self.memory.cur_frame = self.cur_frame();
         }
         match frame.return_to_block {
             StackPopCleanup::MarkStatic(mutable) => {
@@ -2267,7 +2265,7 @@ fn fn_once_adapter_instance<'a, 'tcx>(
     substs: ty::ClosureSubsts<'tcx>,
 ) -> ty::Instance<'tcx> {
     debug!("fn_once_adapter_shim({:?}, {:?})", closure_did, substs);
-    let fn_once = tcx.lang_items.fn_once_trait().unwrap();
+    let fn_once = tcx.lang_items().fn_once_trait().unwrap();
     let call_once = tcx.associated_items(fn_once)
         .find(|it| it.kind == ty::AssociatedKind::Method)
         .unwrap()
@@ -2346,7 +2344,7 @@ pub fn resolve<'a, 'tcx>(
                 ty::InstanceDef::Intrinsic(def_id)
             }
             _ => {
-                if Some(def_id) == tcx.lang_items.drop_in_place_fn() {
+                if Some(def_id) == tcx.lang_items().drop_in_place_fn() {
                     let ty = substs.type_at(0);
                     if needs_drop_glue(tcx, ty) {
                         debug!(" => nontrivial drop glue");
@@ -2440,7 +2438,7 @@ fn resolve_associated_item<'a, 'tcx>(
             }
         }
         ::rustc::traits::VtableClosure(closure_data) => {
-            let trait_closure_kind = tcx.lang_items.fn_trait_kind(trait_id).unwrap();
+            let trait_closure_kind = tcx.lang_items().fn_trait_kind(trait_id).unwrap();
             resolve_closure(
                 tcx,
                 closure_data.closure_def_id,
@@ -2461,7 +2459,7 @@ fn resolve_associated_item<'a, 'tcx>(
                 substs: rcvr_substs,
             }
         }
-        ::rustc::traits::VtableBuiltin(..) if Some(trait_id) == tcx.lang_items.clone_trait() => {
+        ::rustc::traits::VtableBuiltin(..) if Some(trait_id) == tcx.lang_items().clone_trait() => {
             ty::Instance {
                 def: ty::InstanceDef::CloneShim(def_id, trait_ref.self_ty()),
                 substs: rcvr_substs
diff --git a/src/librustc_mir/interpret/memory.rs b/src/librustc_mir/interpret/memory.rs
index 7454f1c908..9a99f50cdf 100644
--- a/src/librustc_mir/interpret/memory.rs
+++ b/src/librustc_mir/interpret/memory.rs
@@ -268,7 +268,7 @@ pub struct Memory<'a, 'tcx, M: Machine<'tcx>> {
     writes_are_aligned: Cell<bool>,
 
     /// The current stack frame.  Used to check accesses against locks.
-    cur_frame: usize,
+    pub(super) cur_frame: usize,
 }
 
 impl<'a, 'tcx, M: Machine<'tcx>> Memory<'a, 'tcx, M> {
@@ -530,10 +530,6 @@ impl<'a, 'tcx, M: Machine<'tcx>> Memory<'a, 'tcx, M> {
         }
         Ok(())
     }
-
-    pub(crate) fn set_cur_frame(&mut self, cur_frame: usize) {
-        self.cur_frame = cur_frame;
-    }
 }
 
 /// Locking
diff --git a/src/librustc_mir/interpret/step.rs b/src/librustc_mir/interpret/step.rs
index e7d5a83532..3dc74368fe 100644
--- a/src/librustc_mir/interpret/step.rs
+++ b/src/librustc_mir/interpret/step.rs
@@ -164,7 +164,7 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
                 }
             }
             EndRegion(ce) => {
-                self.end_region(ce)?;
+                self.end_region(Some(ce))?;
             }
 
             // Defined to do nothing. These are added by optimization passes, to avoid changing the
diff --git a/src/librustc_mir/interpret/validation.rs b/src/librustc_mir/interpret/validation.rs
index 7dfc781520..9a16a4ec15 100644
--- a/src/librustc_mir/interpret/validation.rs
+++ b/src/librustc_mir/interpret/validation.rs
@@ -45,6 +45,7 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
         if self.tcx.sess.opts.debugging_opts.mir_emit_validate == 0 {
             return Ok(());
         }
+        debug_assert!(self.memory.cur_frame == self.cur_frame());
 
         // HACK: Determine if this method is whitelisted and hence we do not perform any validation.
         // We currently insta-UB on anything passing around uninitialized memory, so we have to whitelist
@@ -55,17 +56,17 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
             use regex::Regex;
             lazy_static! {
                 static ref RE: Regex = Regex::new("^(\
-                    std::mem::uninitialized::|\
-                    std::mem::forget::|\
+                    (std|alloc::heap::__core)::mem::uninitialized::|\
+                    (std|alloc::heap::__core)::mem::forget::|\
                     <(std|alloc)::heap::Heap as (std::heap|alloc::allocator)::Alloc>::|\
-                    <std::mem::ManuallyDrop<T>><.*>::new$|\
-                    <std::mem::ManuallyDrop<T> as std::ops::DerefMut><.*>::deref_mut$|\
-                    std::ptr::read::|\
+                    <(std|alloc::heap::__core)::mem::ManuallyDrop<T>><.*>::new$|\
+                    <(std|alloc::heap::__core)::mem::ManuallyDrop<T> as std::ops::DerefMut><.*>::deref_mut$|\
+                    (std|alloc::heap::__core)::ptr::read::|\
                     \
                     <std::sync::Arc<T>><.*>::inner$|\
                     <std::sync::Arc<T>><.*>::drop_slow$|\
                     (std::heap|alloc::allocator)::Layout::for_value::|\
-                    std::mem::(size|align)_of_val::\
+                    (std|alloc::heap::__core)::mem::(size|align)_of_val::\
                 )").unwrap();
             }
             // Now test
@@ -93,7 +94,8 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
                 if query.mutbl == MutMutable {
                     let lft = DynamicLifetime {
                         frame: self.cur_frame(),
-                        region: Some(scope),
+                        region: Some(scope), // Notably, we only ever suspend things for given regions.
+                        // Suspending for the entire function does not make any sense.
                     };
                     trace!("Suspending {:?} until {:?}", query, scope);
                     self.suspended.entry(lft).or_insert_with(Vec::new).push(
@@ -106,17 +108,30 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
         self.validate(query, mode)
     }
 
-    pub(crate) fn end_region(&mut self, scope: region::Scope) -> EvalResult<'tcx> {
-        self.memory.locks_lifetime_ended(Some(scope));
-        // Recover suspended lvals
-        let lft = DynamicLifetime {
-            frame: self.cur_frame(),
-            region: Some(scope),
-        };
-        if let Some(queries) = self.suspended.remove(&lft) {
-            for query in queries {
-                trace!("Recovering {:?} from suspension", query);
-                self.validate(query, ValidationMode::Recover(scope))?;
+    /// Release locks and executes suspensions of the given region (or the entire fn, in case of None).
+    pub(crate) fn end_region(&mut self, scope: Option<region::Scope>) -> EvalResult<'tcx> {
+        debug_assert!(self.memory.cur_frame == self.cur_frame());
+        self.memory.locks_lifetime_ended(scope);
+        match scope {
+            Some(scope) => {
+                // Recover suspended lvals
+                let lft = DynamicLifetime {
+                    frame: self.cur_frame(),
+                    region: Some(scope),
+                };
+                if let Some(queries) = self.suspended.remove(&lft) {
+                    for query in queries {
+                        trace!("Recovering {:?} from suspension", query);
+                        self.validate(query, ValidationMode::Recover(scope))?;
+                    }
+                }
+            }
+            None => {
+                // Clean suspension table of current frame
+                let cur_frame = self.cur_frame();
+                self.suspended.retain(|lft, _| {
+                    lft.frame != cur_frame // keep only what is in the other (lower) frames
+                });
             }
         }
         Ok(())
@@ -543,7 +558,7 @@ impl<'a, 'tcx, M: Machine<'tcx>> EvalContext<'a, 'tcx, M> {
                 Ok(())
             }
             TyAdt(adt, subst) => {
-                if Some(adt.did) == self.tcx.lang_items.unsafe_cell_type() &&
+                if Some(adt.did) == self.tcx.lang_items().unsafe_cell_type() &&
                     query.mutbl == MutImmutable
                 {
                     // No locks for shared unsafe cells.  Also no other validation, the only field is private anyway.
diff --git a/tests/compile-fail/deallocate-bad-alignment.rs b/tests/compile-fail/deallocate-bad-alignment.rs
index a0bcffa47d..c1ae7477c8 100644
--- a/tests/compile-fail/deallocate-bad-alignment.rs
+++ b/tests/compile-fail/deallocate-bad-alignment.rs
@@ -7,7 +7,6 @@ use alloc::allocator::*;
 
 // error-pattern: tried to deallocate or reallocate using incorrect alignment or size
 
-use alloc::heap::*;
 fn main() {
     unsafe {
         let x = Heap.alloc(Layout::from_size_align_unchecked(1, 1)).unwrap();
diff --git a/tests/compile-fail/deallocate-bad-size.rs b/tests/compile-fail/deallocate-bad-size.rs
index d8c4493043..5577f10736 100644
--- a/tests/compile-fail/deallocate-bad-size.rs
+++ b/tests/compile-fail/deallocate-bad-size.rs
@@ -7,7 +7,6 @@ use alloc::allocator::*;
 
 // error-pattern: tried to deallocate or reallocate using incorrect alignment or size
 
-use alloc::heap::*;
 fn main() {
     unsafe {
         let x = Heap.alloc(Layout::from_size_align_unchecked(1, 1)).unwrap();
diff --git a/tests/compile-fail/deallocate-twice.rs b/tests/compile-fail/deallocate-twice.rs
index fd3cccfd53..e11df0eb41 100644
--- a/tests/compile-fail/deallocate-twice.rs
+++ b/tests/compile-fail/deallocate-twice.rs
@@ -7,7 +7,6 @@ use alloc::allocator::*;
 
 // error-pattern: tried to deallocate dangling pointer
 
-use alloc::heap::*;
 fn main() {
     unsafe {
         let x = Heap.alloc(Layout::from_size_align_unchecked(1, 1)).unwrap();
diff --git a/tests/compile-fail/reallocate-bad-alignment-2.rs b/tests/compile-fail/reallocate-bad-alignment-2.rs
index 41da885a2c..cd6214440f 100644
--- a/tests/compile-fail/reallocate-bad-alignment-2.rs
+++ b/tests/compile-fail/reallocate-bad-alignment-2.rs
@@ -7,7 +7,6 @@ use alloc::allocator::*;
 
 // error-pattern: tried to deallocate or reallocate using incorrect alignment or size
 
-use alloc::heap::*;
 fn main() {
     unsafe {
         let x = Heap.alloc(Layout::from_size_align_unchecked(1, 1)).unwrap();
diff --git a/tests/compile-fail/reallocate-bad-alignment.rs b/tests/compile-fail/reallocate-bad-alignment.rs
index be4bc5589c..da5fe1d819 100644
--- a/tests/compile-fail/reallocate-bad-alignment.rs
+++ b/tests/compile-fail/reallocate-bad-alignment.rs
@@ -7,7 +7,6 @@ use alloc::allocator::*;
 
 // error-pattern: tried to deallocate or reallocate using incorrect alignment or size
 
-use alloc::heap::*;
 fn main() {
     unsafe {
         let x = Heap.alloc(Layout::from_size_align_unchecked(1, 2)).unwrap();
diff --git a/tests/compile-fail/reallocate-bad-size.rs b/tests/compile-fail/reallocate-bad-size.rs
index 2e5a641838..953178742c 100644
--- a/tests/compile-fail/reallocate-bad-size.rs
+++ b/tests/compile-fail/reallocate-bad-size.rs
@@ -7,7 +7,6 @@ use alloc::allocator::*;
 
 // error-pattern: tried to deallocate or reallocate using incorrect alignment or size
 
-use alloc::heap::*;
 fn main() {
     unsafe {
         let x = Heap.alloc(Layout::from_size_align_unchecked(1, 1)).unwrap();
diff --git a/tests/compile-fail/reallocate-dangling.rs b/tests/compile-fail/reallocate-dangling.rs
index 54636b5d20..6225879a5a 100644
--- a/tests/compile-fail/reallocate-dangling.rs
+++ b/tests/compile-fail/reallocate-dangling.rs
@@ -7,7 +7,6 @@ use alloc::allocator::*;
 
 // error-pattern: dangling pointer was dereferenced
 
-use alloc::heap::*;
 fn main() {
     unsafe {
         let x = Heap.alloc(Layout::from_size_align_unchecked(1, 1)).unwrap();
diff --git a/tests/run-pass-fullmir/u128.rs b/tests/run-pass-fullmir/u128.rs
index a1fb96ef4a..a05308acbe 100644
--- a/tests/run-pass-fullmir/u128.rs
+++ b/tests/run-pass-fullmir/u128.rs
@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// compile-flags: -Zmir-emit-validate=0
-
 #![feature(i128_type)]
 
 fn b<T>(t: T) -> T { t }
diff --git a/tests/run-pass-fullmir/unsized-tuple-impls.rs b/tests/run-pass-fullmir/unsized-tuple-impls.rs
index acaedebbf9..ccb6883e87 100644
--- a/tests/run-pass-fullmir/unsized-tuple-impls.rs
+++ b/tests/run-pass-fullmir/unsized-tuple-impls.rs
@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// compile-flags: -Zmir-emit-validate=0
-
 #![feature(unsized_tuple_coercion)]
 use std::mem;
 
diff --git a/tests/run-pass/dst-field-align.rs b/tests/run-pass/dst-field-align.rs
index fd44e04ee2..5631b65ed9 100644
--- a/tests/run-pass/dst-field-align.rs
+++ b/tests/run-pass/dst-field-align.rs
@@ -8,9 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// FIXME: Broken by #296
-// compile-flags: -Zmir-emit-validate=0
-
 #![allow(dead_code)]
 
 struct Foo<T: ?Sized> {
diff --git a/tests/run-pass/mir_coercions.rs b/tests/run-pass/mir_coercions.rs
index 194bc9be0a..36155297e3 100644
--- a/tests/run-pass/mir_coercions.rs
+++ b/tests/run-pass/mir_coercions.rs
@@ -8,9 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// FIXME: investigate again once #296 is fixed
-// compile-flags: -Zmir-emit-validate=0
-
 #![feature(coerce_unsized, unsize)]
 
 use std::ops::CoerceUnsized;
diff --git a/tests/run-pass/non_capture_closure_to_fn_ptr.rs b/tests/run-pass/non_capture_closure_to_fn_ptr.rs
index 0578ecbbb1..c9daff9c9f 100644
--- a/tests/run-pass/non_capture_closure_to_fn_ptr.rs
+++ b/tests/run-pass/non_capture_closure_to_fn_ptr.rs
@@ -1,6 +1,3 @@
-// FIXME: investigate again once #296 is fixed
-// compile-flags: -Zmir-emit-validate=0
-
 // allow(const_err) to work around a bug in warnings
 #[allow(const_err)]
 static FOO: fn() = || { assert_ne!(42, 43) };
diff --git a/tests/run-pass/pointers.rs b/tests/run-pass/pointers.rs
index 7d34d564ea..f3ae3ab913 100644
--- a/tests/run-pass/pointers.rs
+++ b/tests/run-pass/pointers.rs
@@ -1,5 +1,3 @@
-// compile-flags: -Zmir-emit-validate=0
-
 fn one_line_ref() -> i16 {
     *&1
 }
diff --git a/tests/run-pass/subslice_array.rs b/tests/run-pass/subslice_array.rs
index ae4a9eb5cf..468cc9f094 100644
--- a/tests/run-pass/subslice_array.rs
+++ b/tests/run-pass/subslice_array.rs
@@ -1,6 +1,3 @@
-// FIXME: investigate again once #296 is fixed
-// compile-flags: -Zmir-emit-validate=0
-
 #![feature(advanced_slice_patterns)]
 #![feature(slice_patterns)]
 
diff --git a/tests/run-pass/tuple_like_enum_variant_constructor_pointer_opt.rs b/tests/run-pass/tuple_like_enum_variant_constructor_pointer_opt.rs
index 426e1360a3..fb57d4f4c1 100644
--- a/tests/run-pass/tuple_like_enum_variant_constructor_pointer_opt.rs
+++ b/tests/run-pass/tuple_like_enum_variant_constructor_pointer_opt.rs
@@ -1,6 +1,3 @@
-// FIXME: investigate again once #296 is fixed
-// compile-flags: -Zmir-emit-validate=0
-
 fn main() {
     let x = 5;
     assert_eq!(Some(&x).map(Some), Some(Some(&x)));