diff --git a/src/librustc_driver/lib.rs b/src/librustc_driver/lib.rs
index 33c009cf329..7f15f5e87d9 100644
--- a/src/librustc_driver/lib.rs
+++ b/src/librustc_driver/lib.rs
@@ -378,13 +378,13 @@ pub fn handle_options(mut args: Vec<String>) -> Option<getopts::Matches> {
     // Don't handle -W help here, because we might first load plugins.
 
     let r = matches.opt_strs("Z");
-    if r.iter().any(|x| x.as_slice() == "help") {
+    if r.iter().any(|x| *x == "help") {
         describe_debug_flags();
         return None;
     }
 
     let cg_flags = matches.opt_strs("C");
-    if cg_flags.iter().any(|x| x.as_slice() == "help") {
+    if cg_flags.iter().any(|x| *x == "help") {
         describe_codegen_flags();
         return None;
     }
diff --git a/src/librustc_trans/back/link.rs b/src/librustc_trans/back/link.rs
index 6057f9d9081..62f8177ed75 100644
--- a/src/librustc_trans/back/link.rs
+++ b/src/librustc_trans/back/link.rs
@@ -140,7 +140,7 @@ pub fn find_crate_name(sess: Option<&Session>,
     if let Some(sess) = sess {
         if let Some(ref s) = sess.opts.crate_name {
             if let Some((attr, ref name)) = attr_crate_name {
-                if s.as_slice() != name.get() {
+                if *s != name.get() {
                     let msg = format!("--crate-name and #[crate_name] are \
                                        required to match, but `{}` != `{}`",
                                       s, name);
@@ -249,7 +249,7 @@ pub fn sanitize(s: &str) -> String {
                 let mut tstr = String::new();
                 for c in c.escape_unicode() { tstr.push(c) }
                 result.push('$');
-                result.push_str(tstr.as_slice().slice_from(1));
+                result.push_str(tstr.slice_from(1));
             }
         }
     }
@@ -669,7 +669,7 @@ fn link_rlib<'a>(sess: &'a Session,
 fn write_rlib_bytecode_object_v1<T: Writer>(writer: &mut T,
                                             bc_data_deflated: &[u8])
                                          -> ::std::io::IoResult<()> {
-    let bc_data_deflated_size: u64 = bc_data_deflated.as_slice().len() as u64;
+    let bc_data_deflated_size: u64 = bc_data_deflated.len() as u64;
 
     try! { writer.write(RLIB_BYTECODE_OBJECT_MAGIC) };
     try! { writer.write_le_u32(1) };
@@ -910,10 +910,10 @@ fn link_args(cmd: &mut Command,
         let args = sess.opts.cg.link_args.as_ref().unwrap_or(&empty_vec);
         let mut args = args.iter().chain(used_link_args.iter());
         if !dylib
-            && (t.options.relocation_model.as_slice() == "pic"
-                || sess.opts.cg.relocation_model.as_ref()
-                   .unwrap_or(&empty_str).as_slice() == "pic")
-            && !args.any(|x| x.as_slice() == "-static") {
+            && (t.options.relocation_model == "pic"
+                || *sess.opts.cg.relocation_model.as_ref()
+                   .unwrap_or(&empty_str) == "pic")
+            && !args.any(|x| *x == "-static") {
             cmd.arg("-pie");
         }
     }
diff --git a/src/librustc_trans/back/lto.rs b/src/librustc_trans/back/lto.rs
index 407f632bee7..a715849ddf6 100644
--- a/src/librustc_trans/back/lto.rs
+++ b/src/librustc_trans/back/lto.rs
@@ -143,7 +143,7 @@ pub fn run(sess: &session::Session, llmod: ModuleRef,
 
     // Internalize everything but the reachable symbols of the current module
     let cstrs: Vec<::std::c_str::CString> =
-        reachable.iter().map(|s| s.as_slice().to_c_str()).collect();
+        reachable.iter().map(|s| s.to_c_str()).collect();
     let arr: Vec<*const i8> = cstrs.iter().map(|c| c.as_ptr()).collect();
     let ptr = arr.as_ptr();
     unsafe {
diff --git a/src/librustc_trans/back/write.rs b/src/librustc_trans/back/write.rs
index e5ffe2675d6..a919fe686ab 100644
--- a/src/librustc_trans/back/write.rs
+++ b/src/librustc_trans/back/write.rs
@@ -363,7 +363,7 @@ unsafe extern "C" fn diagnostic_handler(info: DiagnosticInfoRef, user: *mut c_vo
             let pass_name = pass_name.as_str().expect("got a non-UTF8 pass name from LLVM");
             let enabled = match cgcx.remark {
                 AllPasses => true,
-                SomePasses(ref v) => v.iter().any(|s| s.as_slice() == pass_name),
+                SomePasses(ref v) => v.iter().any(|s| *s == pass_name),
             };
 
             if enabled {
@@ -421,7 +421,7 @@ unsafe fn optimize_and_codegen(cgcx: &CodegenContext,
             // If we're verifying or linting, add them to the function pass
             // manager.
             let addpass = |pass: &str| {
-                pass.as_slice().with_c_str(|s| llvm::LLVMRustAddPass(fpm, s))
+                pass.with_c_str(|s| llvm::LLVMRustAddPass(fpm, s))
             };
             if !config.no_verify { assert!(addpass("verify")); }
 
@@ -433,7 +433,7 @@ unsafe fn optimize_and_codegen(cgcx: &CodegenContext,
             }
 
             for pass in config.passes.iter() {
-                pass.as_slice().with_c_str(|s| {
+                pass.with_c_str(|s| {
                     if !llvm::LLVMRustAddPass(mpm, s) {
                         cgcx.handler.warn(format!("unknown pass {}, ignoring",
                                                   *pass).as_slice());
diff --git a/src/librustc_trans/save/recorder.rs b/src/librustc_trans/save/recorder.rs
index 2102133f97d..f0bb441145c 100644
--- a/src/librustc_trans/save/recorder.rs
+++ b/src/librustc_trans/save/recorder.rs
@@ -163,7 +163,7 @@ impl<'a> FmtStrs<'a> {
         let values = values.iter().map(|s| {
             // Never take more than 1020 chars
             if s.len() > 1020 {
-                s.as_slice().slice_to(1020)
+                s.slice_to(1020)
             } else {
                 s.as_slice()
             }
diff --git a/src/librustc_trans/trans/asm.rs b/src/librustc_trans/trans/asm.rs
index 77102d2db39..e3afe22897e 100644
--- a/src/librustc_trans/trans/asm.rs
+++ b/src/librustc_trans/trans/asm.rs
@@ -122,7 +122,7 @@ pub fn trans_inline_asm<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, ia: &ast::InlineAsm)
     };
 
     let r = ia.asm.get().with_c_str(|a| {
-        constraints.as_slice().with_c_str(|c| {
+        constraints.with_c_str(|c| {
             InlineAsmCall(bcx,
                           a,
                           c,
diff --git a/src/librustc_trans/trans/base.rs b/src/librustc_trans/trans/base.rs
index 9d0e096c71d..3090119788c 100644
--- a/src/librustc_trans/trans/base.rs
+++ b/src/librustc_trans/trans/base.rs
@@ -2739,7 +2739,7 @@ pub fn get_item_val(ccx: &CrateContext, id: ast::NodeId) -> ValueRef {
                                 format!("Illegal null byte in export_name \
                                          value: `{}`", sym).as_slice());
                         }
-                        let g = sym.as_slice().with_c_str(|buf| {
+                        let g = sym.with_c_str(|buf| {
                             llvm::LLVMAddGlobal(ccx.llmod(), llty, buf)
                         });
 
diff --git a/src/librustc_trans/trans/builder.rs b/src/librustc_trans/trans/builder.rs
index 526592181ae..cf940b13846 100644
--- a/src/librustc_trans/trans/builder.rs
+++ b/src/librustc_trans/trans/builder.rs
@@ -774,7 +774,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             let comment_text = format!("{} {}", "#",
                                        sanitized.replace("\n", "\n\t# "));
             self.count_insn("inlineasm");
-            let asm = comment_text.as_slice().with_c_str(|c| {
+            let asm = comment_text.with_c_str(|c| {
                 unsafe {
                     llvm::LLVMConstInlineAsm(Type::func(&[], &Type::void(self.ccx)).to_ref(),
                                              c, noname(), False, False)
diff --git a/src/librustc_trans/trans/context.rs b/src/librustc_trans/trans/context.rs
index fd9d6b8f2c3..3b5197594a1 100644
--- a/src/librustc_trans/trans/context.rs
+++ b/src/librustc_trans/trans/context.rs
@@ -222,14 +222,12 @@ unsafe fn create_context_and_module(sess: &Session, mod_name: &str) -> (ContextR
     sess.target
         .target
         .data_layout
-        .as_slice()
         .with_c_str(|buf| {
         llvm::LLVMSetDataLayout(llmod, buf);
     });
     sess.target
         .target
         .llvm_target
-        .as_slice()
         .with_c_str(|buf| {
         llvm::LLVMRustSetNormalizedTarget(llmod, buf);
     });
diff --git a/src/librustc_trans/trans/debuginfo.rs b/src/librustc_trans/trans/debuginfo.rs
index 555cb000489..6c75086fec6 100644
--- a/src/librustc_trans/trans/debuginfo.rs
+++ b/src/librustc_trans/trans/debuginfo.rs
@@ -824,8 +824,8 @@ pub fn create_global_var_metadata(cx: &CrateContext,
         namespace_node.mangled_name_of_contained_item(var_name.as_slice());
     let var_scope = namespace_node.scope;
 
-    var_name.as_slice().with_c_str(|var_name| {
-        linkage_name.as_slice().with_c_str(|linkage_name| {
+    var_name.with_c_str(|var_name| {
+        linkage_name.with_c_str(|linkage_name| {
             unsafe {
                 llvm::LLVMDIBuilderCreateStaticVariable(DIB(cx),
                                                         var_scope,
@@ -1323,7 +1323,7 @@ pub fn create_function_debug_context<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
         let containing_scope = namespace_node.scope;
         (linkage_name, containing_scope)
     } else {
-        (function_name.as_slice().to_string(), file_metadata)
+        (function_name.clone(), file_metadata)
     };
 
     // Clang sets this parameter to the opening brace of the function's block,
@@ -1332,8 +1332,8 @@ pub fn create_function_debug_context<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 
     let is_local_to_unit = is_node_local_to_unit(cx, fn_ast_id);
 
-    let fn_metadata = function_name.as_slice().with_c_str(|function_name| {
-                          linkage_name.as_slice().with_c_str(|linkage_name| {
+    let fn_metadata = function_name.with_c_str(|function_name| {
+                          linkage_name.with_c_str(|linkage_name| {
             unsafe {
                 llvm::LLVMDIBuilderCreateFunction(
                     DIB(cx),
@@ -1554,7 +1554,7 @@ fn compile_unit_metadata(cx: &CrateContext) {
                                 path_bytes.insert(1, prefix[1]);
                             }
 
-                            path_bytes.as_slice().to_c_str()
+                            path_bytes.to_c_str()
                         }
                     _ => fallback_path(cx)
                 }
@@ -1589,7 +1589,7 @@ fn compile_unit_metadata(cx: &CrateContext) {
     });
 
     fn fallback_path(cx: &CrateContext) -> CString {
-        cx.link_meta().crate_name.as_slice().to_c_str()
+        cx.link_meta().crate_name.to_c_str()
     }
 }
 
@@ -1796,7 +1796,7 @@ fn pointer_type_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
     let pointer_llvm_type = type_of::type_of(cx, pointer_type);
     let (pointer_size, pointer_align) = size_and_align_of(cx, pointer_llvm_type);
     let name = compute_debuginfo_type_name(cx, pointer_type, false);
-    let ptr_metadata = name.as_slice().with_c_str(|name| {
+    let ptr_metadata = name.with_c_str(|name| {
         unsafe {
             llvm::LLVMDIBuilderCreatePointerType(
                 DIB(cx),
@@ -2488,8 +2488,8 @@ fn prepare_enum_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
                              .borrow()
                              .get_unique_type_id_as_string(unique_type_id);
 
-    let enum_metadata = enum_name.as_slice().with_c_str(|enum_name| {
-        unique_type_id_str.as_slice().with_c_str(|unique_type_id_str| {
+    let enum_metadata = enum_name.with_c_str(|enum_name| {
+        unique_type_id_str.with_c_str(|unique_type_id_str| {
             unsafe {
                 llvm::LLVMDIBuilderCreateUnionType(
                 DIB(cx),
@@ -2616,7 +2616,7 @@ fn set_members_of_composite_type(cx: &CrateContext,
                 ComputedMemberOffset => machine::llelement_offset(cx, composite_llvm_type, i)
             };
 
-            member_description.name.as_slice().with_c_str(|member_name| {
+            member_description.name.with_c_str(|member_name| {
                 unsafe {
                     llvm::LLVMDIBuilderCreateMemberType(
                         DIB(cx),
@@ -2656,7 +2656,7 @@ fn create_struct_stub(cx: &CrateContext,
                                               .get_unique_type_id_as_string(unique_type_id);
     let metadata_stub = unsafe {
         struct_type_name.with_c_str(|name| {
-            unique_type_id_str.as_slice().with_c_str(|unique_type_id| {
+            unique_type_id_str.with_c_str(|unique_type_id| {
                 // LLVMDIBuilderCreateStructType() wants an empty array. A null
                 // pointer will lead to hard to trace and debug LLVM assertions
                 // later on in llvm/lib/IR/Value.cpp.
diff --git a/src/librustc_trans/trans/glue.rs b/src/librustc_trans/trans/glue.rs
index fbaf1e65810..4575d8a41e5 100644
--- a/src/librustc_trans/trans/glue.rs
+++ b/src/librustc_trans/trans/glue.rs
@@ -496,7 +496,7 @@ pub fn declare_tydesc<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, t: Ty<'tcx>)
     let llalign = llalign_of(ccx, llty);
     let name = mangle_internal_name_by_type_and_seq(ccx, t, "tydesc");
     debug!("+++ declare_tydesc {} {}", ppaux::ty_to_string(ccx.tcx(), t), name);
-    let gvar = name.as_slice().with_c_str(|buf| {
+    let gvar = name.with_c_str(|buf| {
         unsafe {
             llvm::LLVMAddGlobal(ccx.llmod(), ccx.tydesc_type().to_ref(), buf)
         }