Remove unused imports

src/librustc_trans/base.rs

@@ -79,7 +79,6 @@ use util::nodemap::{NodeSet, FxHashMap, FxHashSet};
 
 use libc::c_uint;
 use std::ffi::{CStr, CString};
-use std::cell::RefCell;
 use std::rc::Rc;
 use std::str;
 use std::i32;

src/librustc_trans/builder.rs

@@ -14,12 +14,10 @@ use llvm;
 use llvm::{AtomicRmwBinOp, AtomicOrdering, SynchronizationScope, AsmDialect};
 use llvm::{Opcode, IntPredicate, RealPredicate, False, OperandBundleDef};
 use llvm::{ValueRef, BasicBlockRef, BuilderRef, ModuleRef};
-use base;
 use common::*;
 use machine::llalign_of_pref;
 use type_::Type;
 use value::Value;
-use util::nodemap::FxHashMap;
 use libc::{c_uint, c_char};
 
 use std::borrow::Cow;

src/librustc_trans/context.rs

@@ -15,7 +15,6 @@ use middle::cstore::LinkMeta;
 use rustc::hir::def::ExportMap;
 use rustc::hir::def_id::DefId;
 use rustc::traits;
-use base;
 use debuginfo;
 use declare;
 use glue::DropGlueKind;