diff --git a/.appveyor.yml b/.appveyor.yml
index 391ff042daf..c3d575403cb 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -17,16 +17,21 @@ cache:
     - '%USERPROFILE%\.rustup'
 
 install:
+    # Compute the rust version we use
+    - set /p RUSTC_HASH=<rust-version
     # Install Rust
     - curl -sSf --retry 3 -o rustup-init.exe https://win.rustup.rs/
     - rustup-init.exe -y --default-host %TARGET% --default-toolchain stable
     - set PATH=%USERPROFILE%\.cargo\bin;%PATH%
+    - rustup default stable
+    - rustup uninstall beta
+    - rustup update
     # Install "master" toolchain
     - cargo install rustup-toolchain-install-master & exit 0
-    - set /p RUSTC_HASH=<rust-version
     - rustup-toolchain-install-master -f -n master %RUSTC_HASH% -c cargo -c rust-src
     - rustup default master
     - rustc --version
+    - cargo --version
 
 build_script:
     - set RUSTFLAGS=-C debug-assertions
diff --git a/.travis.yml b/.travis.yml
index 269dc28ca02..446fab79411 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -33,12 +33,15 @@ before_script:
 # Install Rust ("stable" toolchain for better caching, it is just used to build rustup-toolchain-install-master)
 - curl https://build.travis-ci.org/files/rustup-init.sh -sSf | sh -s -- -y --default-toolchain stable
 - export PATH=$HOME/.cargo/bin:$PATH
+- rustup default stable
+- rustup uninstall beta
 - rustup update
 # Install "master" toolchain
 - cargo install rustup-toolchain-install-master || echo "rustup-toolchain-install-master already installed"
 - travis_retry rustup-toolchain-install-master -f -n master $RUSTC_HASH -c rust-src
 - rustup default master
 - rustc --version
+- cargo --version
 
 script:
 - ./travis.sh
diff --git a/Cargo.toml b/Cargo.toml
index 6e34d6c3d5d..5a5c774169c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -59,5 +59,5 @@ cargo_miri = ["cargo_metadata", "directories", "rustc_version"]
 rustc_tests = []
 
 [dev-dependencies]
-compiletest_rs = { version = "0.3.22", features = ["tmp", "stable"] }
+compiletest_rs = { version = "0.3.23", features = ["tmp"] }
 colored = "1.6"
diff --git a/rust-version b/rust-version
index 60dae7291d6..08d4c1dc234 100644
--- a/rust-version
+++ b/rust-version
@@ -1 +1 @@
-ea3ba36f3f4b7f0168a27d23c499efeb2304e2d5
+084beb83e0e87d673d5fabc844d28e8e8ae2ab4c
diff --git a/src/bin/miri-rustc-tests.rs b/src/bin/miri-rustc-tests.rs
index 3b4ad841591..5f814fd1986 100644
--- a/src/bin/miri-rustc-tests.rs
+++ b/src/bin/miri-rustc-tests.rs
@@ -46,7 +46,7 @@ impl rustc_driver::Callbacks for MiriCompilerCalls {
                 struct Visitor<'tcx>(TyCtxt<'tcx>);
                 impl<'tcx, 'hir> itemlikevisit::ItemLikeVisitor<'hir> for Visitor<'tcx> {
                     fn visit_item(&mut self, i: &'hir hir::Item) {
-                        if let hir::ItemKind::Fn(.., body_id) = i.node {
+                        if let hir::ItemKind::Fn(.., body_id) = i.kind {
                             if i.attrs.iter().any(|attr| attr.check_name(syntax::symbol::sym::test)) {
                                 let config = MiriConfig {
                                     validate: true,
diff --git a/src/eval.rs b/src/eval.rs
index 667491f8d47..1b7c082ec37 100644
--- a/src/eval.rs
+++ b/src/eval.rs
@@ -63,7 +63,7 @@ pub fn create_ecx<'mir, 'tcx: 'mir>(
         ty::ParamEnv::reveal_all(),
         start_id,
         ecx.tcx.mk_substs(
-            ::std::iter::once(ty::subst::Kind::from(main_ret_ty)))
+            ::std::iter::once(ty::subst::GenericArg::from(main_ret_ty)))
         ).unwrap();
     let start_mir = ecx.load_mir(start_instance.def, None)?;
 
diff --git a/src/helpers.rs b/src/helpers.rs
index ad30040c2dd..3bee028c5eb 100644
--- a/src/helpers.rs
+++ b/src/helpers.rs
@@ -211,7 +211,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             fn visit_value(&mut self, v: MPlaceTy<'tcx, Tag>) -> InterpResult<'tcx>
             {
                 trace!("UnsafeCellVisitor: {:?} {:?}", *v, v.layout.ty);
-                let is_unsafe_cell = match v.layout.ty.sty {
+                let is_unsafe_cell = match v.layout.ty.kind {
                     ty::Adt(adt, _) => Some(adt.did) == self.ecx.tcx.lang_items().unsafe_cell_type(),
                     _ => false,
                 };
diff --git a/src/shims/io.rs b/src/shims/io.rs
index 180748a0755..6f8785891c2 100644
--- a/src/shims/io.rs
+++ b/src/shims/io.rs
@@ -5,13 +5,23 @@ use std::io::Read;
 use crate::stacked_borrows::Tag;
 use crate::*;
 
-#[derive(Default)]
 pub struct FileHandler {
     files: HashMap<i32, File>,
     flags: HashMap<i32, i32>,
     low: i32,
 }
 
+impl Default for FileHandler {
+    fn default() -> Self {
+        FileHandler {
+            files: Default::default(),
+            flags: Default::default(),
+            // 0, 1 and 2 are reserved for stdin, stdout and stderr
+            low: 3,
+        }
+    }
+}
+
 impl<'mir, 'tcx> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
     fn open(
diff --git a/src/shims/mod.rs b/src/shims/mod.rs
index 981185d252e..3df5b839e5d 100644
--- a/src/shims/mod.rs
+++ b/src/shims/mod.rs
@@ -1,11 +1,11 @@
+pub mod dlsym;
+pub mod env;
 pub mod foreign_items;
 pub mod intrinsics;
 pub mod tls;
-pub mod dlsym;
-pub mod env;
 pub mod io;
 
-use rustc::{ty, mir};
+use rustc::{mir, ty};
 
 use crate::*;
 
@@ -19,7 +19,11 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         ret: Option<mir::BasicBlock>,
     ) -> InterpResult<'tcx, Option<&'mir mir::Body<'tcx>>> {
         let this = self.eval_context_mut();
-        trace!("eval_fn_call: {:#?}, {:?}", instance, dest.map(|place| *place));
+        trace!(
+            "eval_fn_call: {:#?}, {:?}",
+            instance,
+            dest.map(|place| *place)
+        );
 
         // First, run the common hooks also supported by CTFE.
         if this.hook_fn(instance, args, dest)? {
@@ -28,27 +32,10 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         }
         // There are some more lang items we want to hook that CTFE does not hook (yet).
         if this.tcx.lang_items().align_offset_fn() == Some(instance.def.def_id()) {
-
-            let n = {
-                let ptr = this.force_ptr(this.read_scalar(args[0])?.not_undef()?)?;
-                let align = this.force_bits(
-                    this.read_scalar(args[1])?.not_undef()?,
-                    this.pointer_size()
-                )? as usize;
-
-                let stride = this.memory().get(ptr.alloc_id)?.align.bytes() as usize;
-                // if the allocation alignment is at least the required alignment, we use the
-                // libcore implementation
-                if stride >= align {
-                    ((stride + ptr.offset.bytes() as usize) as *const ())
-                        .align_offset(align) as u128
-                } else {
-                    u128::max_value()
-                }
-            };
-
             let dest = dest.unwrap();
-            let n = this.truncate(n, dest.layout);
+            let n = this
+                .align_offset(args[0], args[1])?
+                .unwrap_or_else(|| this.truncate(u128::max_value(), dest.layout));
             this.write_scalar(Scalar::from_uint(n, dest.layout.size), dest)?;
             this.goto_block(ret)?;
             return Ok(None);
@@ -66,4 +53,39 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         // Otherwise, load the MIR.
         Ok(Some(this.load_mir(instance.def, None)?))
     }
+
+    fn align_offset(
+        &mut self,
+        ptr_op: OpTy<'tcx, Tag>,
+        align_op: OpTy<'tcx, Tag>,
+    ) -> InterpResult<'tcx, Option<u128>> {
+        let this = self.eval_context_mut();
+
+        let req_align = this.force_bits(
+            this.read_scalar(align_op)?.not_undef()?,
+            this.pointer_size(),
+        )? as usize;
+
+        // FIXME: This should actually panic in the interpreted program
+        if !req_align.is_power_of_two() {
+            throw_unsup_format!("Required alignment should always be a power of two")
+        }
+
+        let ptr_scalar = this.read_scalar(ptr_op)?.not_undef()?;
+
+        if let Ok(ptr) = this.force_ptr(ptr_scalar) {
+            let cur_align = this.memory().get(ptr.alloc_id)?.align.bytes() as usize;
+            if cur_align >= req_align {
+                // if the allocation alignment is at least the required alignment we use the
+                // libcore implementation
+                return Ok(Some(
+                    (this.force_bits(ptr_scalar, this.pointer_size())? as *const i8)
+                        .align_offset(req_align) as u128,
+                ));
+            }
+        }
+        // If the allocation alignment is smaller than then required alignment or the pointer was
+        // actually an integer, we return `None`
+        Ok(None)
+    }
 }
diff --git a/src/stacked_borrows.rs b/src/stacked_borrows.rs
index 01ed6ec225d..5258cbb5485 100644
--- a/src/stacked_borrows.rs
+++ b/src/stacked_borrows.rs
@@ -435,7 +435,7 @@ impl<'tcx> Stacks {
 
         Stacks {
             stacks: RefCell::new(RangeMap::new(size, stack)),
-            global: extra, 
+            global: extra,
         }
     }
 
@@ -460,7 +460,7 @@ impl Stacks {
     pub fn new_allocation(
         id: AllocId,
         size: Size,
-        extra: MemoryExtra, 
+        extra: MemoryExtra,
         kind: MemoryKind<MiriMemoryKind>,
     ) -> (Self, Tag) {
         let (tag, perm) = match kind {
@@ -616,7 +616,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         // Cannot use `builtin_deref` because that reports *immutable* for `Box`,
         // making it useless.
         fn qualify(ty: ty::Ty<'_>, kind: RetagKind) -> Option<(RefKind, bool)> {
-            match ty.sty {
+            match ty.kind {
                 // References are simple.
                 ty::Ref(_, _, MutMutable) =>
                     Some((RefKind::Unique { two_phase: kind == RetagKind::TwoPhase}, kind == RetagKind::FnEntry)),
diff --git a/test-cargo-miri/Cargo.lock b/test-cargo-miri/Cargo.lock
index 2a6a32a18f0..70476fbdcb0 100644
--- a/test-cargo-miri/Cargo.lock
+++ b/test-cargo-miri/Cargo.lock
@@ -25,22 +25,22 @@ version = "0.1.0"
 dependencies = [
  "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_cpus 1.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "cfg-if"
-version = "0.1.9"
+version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "getrandom"
-version = "0.1.11"
+version = "0.1.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "cfg-if 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.62 (registry+https://github.com/rust-lang/crates.io-index)",
- "wasi 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "wasi 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -68,13 +68,13 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "rand"
-version = "0.7.0"
+version = "0.7.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "getrandom 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "getrandom 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.62 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_chacha 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand_core 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_hc 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_pcg 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -85,15 +85,15 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "c2-chacha 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand_core 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "rand_core"
-version = "0.5.0"
+version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "getrandom 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "getrandom 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -101,7 +101,7 @@ name = "rand_hc"
 version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "rand_core 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -110,27 +110,27 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "autocfg 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand_core 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "wasi"
-version = "0.5.0"
+version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [metadata]
 "checksum autocfg 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "b671c8fb71b457dd4ae18c4ba1e59aa81793daacc361d82fcd410cef0d491875"
 "checksum byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)" = "a7c3dd8985a7111efc5c80b44e23ecdd8c007de8ade3b96595387e812b957cf5"
 "checksum c2-chacha 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7d64d04786e0f528460fc884753cf8dddcc466be308f6026f8e355c41a0e4101"
-"checksum cfg-if 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)" = "b486ce3ccf7ffd79fdeb678eac06a9e6c09fc88d33836340becb8fffe87c5e33"
-"checksum getrandom 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)" = "fc344b02d3868feb131e8b5fe2b9b0a1cc42942679af493061fc13b853243872"
+"checksum cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)" = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
+"checksum getrandom 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)" = "473a1265acc8ff1e808cd0a1af8cee3c2ee5200916058a2ca113c29f2d903571"
 "checksum lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 "checksum libc 0.2.62 (registry+https://github.com/rust-lang/crates.io-index)" = "34fcd2c08d2f832f376f4173a231990fa5aef4e99fb569867318a227ef4c06ba"
 "checksum num_cpus 1.10.1 (registry+https://github.com/rust-lang/crates.io-index)" = "bcef43580c035376c0705c42792c294b66974abbfd2789b511784023f71f3273"
 "checksum ppv-lite86 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)" = "e3cbf9f658cdb5000fcf6f362b8ea2ba154b9f146a61c7a20d647034c6b6561b"
-"checksum rand 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d47eab0e83d9693d40f825f86948aa16eff6750ead4bdffc4ab95b8b3a7f052c"
+"checksum rand 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)" = "3ae1b169243eaf61759b8475a998f0a385e42042370f3a7dbaf35246eacc8412"
 "checksum rand_chacha 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "03a2a90da8c7523f554344f921aa97283eadf6ac484a6d2a7d0212fa7f8d6853"
-"checksum rand_core 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "615e683324e75af5d43d8f7a39ffe3ee4a9dc42c5c701167a71dc59c3a493aca"
+"checksum rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "90bde5296fc891b0cef12a6d03ddccc162ce7b2aff54160af9338f8d40df6d19"
 "checksum rand_hc 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ca3129af7b92a17112d59ad498c6f81eaf463253766b90396d39ea7a39d6613c"
 "checksum rand_pcg 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3e196346cbbc5c70c77e7b4926147ee8e383a38ee4d15d58a08098b169e492b6"
-"checksum wasi 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fd5442abcac6525a045cc8c795aedb60da7a2e5e89c7bf18a0d5357849bb23c7"
+"checksum wasi 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b89c3ce4ce14bdc6fb6beaf9ec7928ca331de5df7e5ea278375642a2f478570d"
diff --git a/tests/run-pass/aligned_utf8_check.rs b/tests/run-pass/aligned_utf8_check.rs
index 202856b3bde..6c6ff6b6173 100644
--- a/tests/run-pass/aligned_utf8_check.rs
+++ b/tests/run-pass/aligned_utf8_check.rs
@@ -1,13 +1,6 @@
 fn main() {
     const N: usize = 10;
-
-    let x = vec![0x4141u16; N];
-
-    let mut y: Vec<u8> = unsafe { std::mem::transmute(x) };
-    unsafe { y.set_len(2 * N) };
-
-    println!("{:?}", std::str::from_utf8(&y).unwrap());
-
-    let mut x: Vec<u16> = unsafe { std::mem::transmute(y) };
-    unsafe { x.set_len(N) };
+    let vec = vec![0x4141414141414141u64; N];
+    let content = unsafe { std::slice::from_raw_parts(vec.as_ptr() as *const u8, 8 * N) };
+    println!("{:?}", std::str::from_utf8(content).unwrap());
 }
diff --git a/tests/run-pass/aligned_utf8_check.stdout b/tests/run-pass/aligned_utf8_check.stdout
index 8d08312cac7..66d43994815 100644
--- a/tests/run-pass/aligned_utf8_check.stdout
+++ b/tests/run-pass/aligned_utf8_check.stdout
@@ -1 +1 @@
-"AAAAAAAAAAAAAAAAAAAA"
+"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"