diff --git a/Cargo.lock b/Cargo.lock
index f33d7ff12febf..48bc269ebb654 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3092,7 +3092,6 @@ dependencies = [
  "rustc-rayon-core",
  "rustc_apfloat",
  "rustc_data_structures",
- "rustc_error_codes",
  "rustc_errors",
  "rustc_feature",
  "rustc_hir",
@@ -3358,7 +3357,6 @@ dependencies = [
  "log",
  "rustc",
  "rustc_data_structures",
- "rustc_error_codes",
  "rustc_errors",
  "rustc_hir",
  "rustc_index",
@@ -3375,7 +3373,6 @@ version = "0.0.0"
 dependencies = [
  "log",
  "rustc_data_structures",
- "rustc_error_codes",
  "rustc_errors",
  "rustc_feature",
  "rustc_parse",
@@ -3391,7 +3388,6 @@ dependencies = [
  "fmt_macros",
  "log",
  "rustc_data_structures",
- "rustc_error_codes",
  "rustc_errors",
  "rustc_expand",
  "rustc_feature",
@@ -3445,7 +3441,6 @@ dependencies = [
  "rustc_apfloat",
  "rustc_codegen_utils",
  "rustc_data_structures",
- "rustc_error_codes",
  "rustc_errors",
  "rustc_fs_util",
  "rustc_hir",
@@ -3675,7 +3670,6 @@ dependencies = [
  "log",
  "rustc",
  "rustc_data_structures",
- "rustc_error_codes",
  "rustc_errors",
  "rustc_feature",
  "rustc_hir",
@@ -3716,7 +3710,6 @@ dependencies = [
  "memmap",
  "rustc",
  "rustc_data_structures",
- "rustc_error_codes",
  "rustc_errors",
  "rustc_expand",
  "rustc_hir",
@@ -3744,7 +3737,6 @@ dependencies = [
  "rustc",
  "rustc_apfloat",
  "rustc_data_structures",
- "rustc_error_codes",
  "rustc_errors",
  "rustc_hir",
  "rustc_index",
@@ -3767,7 +3759,6 @@ dependencies = [
  "rustc",
  "rustc_apfloat",
  "rustc_data_structures",
- "rustc_error_codes",
  "rustc_errors",
  "rustc_hir",
  "rustc_index",
@@ -3786,7 +3777,6 @@ dependencies = [
  "bitflags",
  "log",
  "rustc_data_structures",
- "rustc_error_codes",
  "rustc_errors",
  "rustc_feature",
  "rustc_lexer",
@@ -3804,7 +3794,6 @@ dependencies = [
  "log",
  "rustc",
  "rustc_data_structures",
- "rustc_error_codes",
  "rustc_errors",
  "rustc_feature",
  "rustc_hir",
@@ -3820,7 +3809,6 @@ name = "rustc_plugin_impl"
 version = "0.0.0"
 dependencies = [
  "rustc",
- "rustc_error_codes",
  "rustc_errors",
  "rustc_hir",
  "rustc_lint",
@@ -3836,7 +3824,6 @@ dependencies = [
  "log",
  "rustc",
  "rustc_data_structures",
- "rustc_error_codes",
  "rustc_errors",
  "rustc_hir",
  "rustc_span",
@@ -3854,7 +3841,6 @@ dependencies = [
  "rustc",
  "rustc_ast_lowering",
  "rustc_data_structures",
- "rustc_error_codes",
  "rustc_errors",
  "rustc_expand",
  "rustc_feature",
@@ -3890,7 +3876,6 @@ dependencies = [
  "log",
  "num_cpus",
  "rustc_data_structures",
- "rustc_error_codes",
  "rustc_errors",
  "rustc_feature",
  "rustc_fs_util",
@@ -3973,7 +3958,6 @@ dependencies = [
  "log",
  "rustc",
  "rustc_data_structures",
- "rustc_error_codes",
  "rustc_errors",
  "rustc_hir",
  "rustc_index",
@@ -4493,7 +4477,6 @@ version = "0.0.0"
 dependencies = [
  "log",
  "rustc_data_structures",
- "rustc_error_codes",
  "rustc_errors",
  "rustc_feature",
  "rustc_index",
diff --git a/src/librustc/Cargo.toml b/src/librustc/Cargo.toml
index 323ce3b6cbb6d..b65635be54a3f 100644
--- a/src/librustc/Cargo.toml
+++ b/src/librustc/Cargo.toml
@@ -37,5 +37,4 @@ byteorder = { version = "1.3" }
 chalk-engine = { version = "0.9.0", default-features=false }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
 measureme = "0.7.1"
-rustc_error_codes = { path = "../librustc_error_codes" }
 rustc_session = { path = "../librustc_session" }
diff --git a/src/librustc/hir/check_attr.rs b/src/librustc/hir/check_attr.rs
index 5a4d7ceea2734..86eab3d92d366 100644
--- a/src/librustc/hir/check_attr.rs
+++ b/src/librustc/hir/check_attr.rs
@@ -8,7 +8,6 @@ use crate::hir::map::Map;
 use crate::ty::query::Providers;
 use crate::ty::TyCtxt;
 
-use rustc_error_codes::*;
 use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
diff --git a/src/librustc/infer/error_reporting/mod.rs b/src/librustc/infer/error_reporting/mod.rs
index a2009461fa568..77182b97fd450 100644
--- a/src/librustc/infer/error_reporting/mod.rs
+++ b/src/librustc/infer/error_reporting/mod.rs
@@ -65,7 +65,6 @@ use crate::ty::{
     Region, Ty, TyCtxt, TypeFoldable,
 };
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
-use rustc_error_codes::*;
 use rustc_errors::{pluralize, struct_span_err};
 use rustc_errors::{Applicability, DiagnosticBuilder, DiagnosticStyledString};
 use rustc_hir as hir;
diff --git a/src/librustc/infer/error_reporting/need_type_info.rs b/src/librustc/infer/error_reporting/need_type_info.rs
index 70f7987faf4cc..9947dea234096 100644
--- a/src/librustc/infer/error_reporting/need_type_info.rs
+++ b/src/librustc/infer/error_reporting/need_type_info.rs
@@ -13,8 +13,6 @@ use rustc_span::symbol::kw;
 use rustc_span::Span;
 use std::borrow::Cow;
 
-use rustc_error_codes::*;
-
 struct FindLocalByTypeVisitor<'a, 'tcx> {
     infcx: &'a InferCtxt<'a, 'tcx>,
     target_ty: Ty<'tcx>,
diff --git a/src/librustc/infer/error_reporting/nice_region_error/different_lifetimes.rs b/src/librustc/infer/error_reporting/nice_region_error/different_lifetimes.rs
index d6e50209f72dd..8f4c643992001 100644
--- a/src/librustc/infer/error_reporting/nice_region_error/different_lifetimes.rs
+++ b/src/librustc/infer/error_reporting/nice_region_error/different_lifetimes.rs
@@ -5,7 +5,6 @@ use crate::infer::error_reporting::nice_region_error::util::AnonymousParamInfo;
 use crate::infer::error_reporting::nice_region_error::NiceRegionError;
 use crate::util::common::ErrorReported;
 
-use rustc_error_codes::*;
 use rustc_errors::struct_span_err;
 
 impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
diff --git a/src/librustc/infer/error_reporting/nice_region_error/named_anon_conflict.rs b/src/librustc/infer/error_reporting/nice_region_error/named_anon_conflict.rs
index 2344d408a43a5..df37f53606b37 100644
--- a/src/librustc/infer/error_reporting/nice_region_error/named_anon_conflict.rs
+++ b/src/librustc/infer/error_reporting/nice_region_error/named_anon_conflict.rs
@@ -5,8 +5,6 @@ use crate::ty;
 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
 use rustc_hir::{FunctionRetTy, TyKind};
 
-use rustc_error_codes::*;
-
 impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
     /// When given a `ConcreteFailure` for a function with parameters containing a named region and
     /// an anonymous region, emit an descriptive diagnostic error.
diff --git a/src/librustc/infer/error_reporting/note.rs b/src/librustc/infer/error_reporting/note.rs
index 6303104e39dd3..11dda71b8cb89 100644
--- a/src/librustc/infer/error_reporting/note.rs
+++ b/src/librustc/infer/error_reporting/note.rs
@@ -5,8 +5,6 @@ use crate::ty::error::TypeError;
 use crate::ty::{self, Region};
 use rustc_errors::{struct_span_err, DiagnosticBuilder};
 
-use rustc_error_codes::*;
-
 impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     pub(super) fn note_region_origin(
         &self,
diff --git a/src/librustc/infer/opaque_types/mod.rs b/src/librustc/infer/opaque_types/mod.rs
index ee214bea7b8fc..fe3a5d149f676 100644
--- a/src/librustc/infer/opaque_types/mod.rs
+++ b/src/librustc/infer/opaque_types/mod.rs
@@ -15,8 +15,6 @@ use rustc_hir::def_id::{DefId, DefIdMap};
 use rustc_hir::Node;
 use rustc_span::Span;
 
-use rustc_error_codes::*;
-
 pub type OpaqueTypeMap<'tcx> = DefIdMap<OpaqueTypeDecl<'tcx>>;
 
 /// Information about the opaque types whose values we
diff --git a/src/librustc/middle/lang_items.rs b/src/librustc/middle/lang_items.rs
index 643359f098b4d..27b769742a9fc 100644
--- a/src/librustc/middle/lang_items.rs
+++ b/src/librustc/middle/lang_items.rs
@@ -24,8 +24,6 @@ use rustc_span::symbol::{sym, Symbol};
 use rustc_span::Span;
 use syntax::ast;
 
-use rustc_error_codes::*;
-
 // The actual lang items defined come at the end of this file in one handy table.
 // So you probably just want to nip down to the end.
 macro_rules! language_item_table {
diff --git a/src/librustc/middle/weak_lang_items.rs b/src/librustc/middle/weak_lang_items.rs
index fdffd1251ce8f..5571f8f2313d5 100644
--- a/src/librustc/middle/weak_lang_items.rs
+++ b/src/librustc/middle/weak_lang_items.rs
@@ -15,8 +15,6 @@ use rustc_span::Span;
 use rustc_target::spec::PanicStrategy;
 use syntax::ast;
 
-use rustc_error_codes::*;
-
 macro_rules! weak_lang_items {
     ($($name:ident, $item:ident, $sym:ident;)*) => (
 
diff --git a/src/librustc/mir/interpret/error.rs b/src/librustc/mir/interpret/error.rs
index 42d896af8014d..349dbd74ad1c9 100644
--- a/src/librustc/mir/interpret/error.rs
+++ b/src/librustc/mir/interpret/error.rs
@@ -16,8 +16,6 @@ use rustc_span::{Pos, Span};
 use rustc_target::spec::abi::Abi;
 use std::{any::Any, env, fmt};
 
-use rustc_error_codes::*;
-
 #[derive(Debug, Copy, Clone, PartialEq, Eq, HashStable, RustcEncodable, RustcDecodable)]
 pub enum ErrorHandled {
     /// Already reported a lint or an error for this evaluation.
diff --git a/src/librustc/traits/error_reporting/mod.rs b/src/librustc/traits/error_reporting/mod.rs
index db3173989ac60..646cb80bffd94 100644
--- a/src/librustc/traits/error_reporting/mod.rs
+++ b/src/librustc/traits/error_reporting/mod.rs
@@ -30,8 +30,6 @@ use rustc_span::{ExpnKind, Span, DUMMY_SP};
 use std::fmt;
 use syntax::ast;
 
-use rustc_error_codes::*;
-
 impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     pub fn report_fulfillment_errors(
         &self,
diff --git a/src/librustc/traits/error_reporting/suggestions.rs b/src/librustc/traits/error_reporting/suggestions.rs
index c09fd3079731c..c18e17581ceb6 100644
--- a/src/librustc/traits/error_reporting/suggestions.rs
+++ b/src/librustc/traits/error_reporting/suggestions.rs
@@ -20,8 +20,6 @@ use rustc_span::symbol::{kw, sym};
 use rustc_span::{MultiSpan, Span, DUMMY_SP};
 use std::fmt;
 
-use rustc_error_codes::*;
-
 impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     crate fn suggest_restricting_param_bound(
         &self,
diff --git a/src/librustc/traits/on_unimplemented.rs b/src/librustc/traits/on_unimplemented.rs
index 1afe153bb1361..669ec5ccc9b98 100644
--- a/src/librustc/traits/on_unimplemented.rs
+++ b/src/librustc/traits/on_unimplemented.rs
@@ -11,8 +11,6 @@ use rustc_span::Span;
 use syntax::ast::{MetaItem, NestedMetaItem};
 use syntax::attr;
 
-use rustc_error_codes::*;
-
 #[derive(Clone, Debug)]
 pub struct OnUnimplementedFormatString(Symbol);
 
diff --git a/src/librustc/traits/query/dropck_outlives.rs b/src/librustc/traits/query/dropck_outlives.rs
index 34866b684de01..2e5ef5adcd30e 100644
--- a/src/librustc/traits/query/dropck_outlives.rs
+++ b/src/librustc/traits/query/dropck_outlives.rs
@@ -6,8 +6,6 @@ use crate::ty::{self, Ty, TyCtxt};
 use rustc_span::source_map::Span;
 use std::iter::FromIterator;
 
-use rustc_error_codes::*;
-
 impl<'cx, 'tcx> At<'cx, 'tcx> {
     /// Given a type `ty` of some value being dropped, computes a set
     /// of "kinds" (types, regions) that must be outlive the execution
diff --git a/src/librustc/traits/specialize/mod.rs b/src/librustc/traits/specialize/mod.rs
index f5199dbdabb2f..e559ea391cde0 100644
--- a/src/librustc/traits/specialize/mod.rs
+++ b/src/librustc/traits/specialize/mod.rs
@@ -25,8 +25,6 @@ use rustc_span::DUMMY_SP;
 use super::util::impl_trait_ref_and_oblig;
 use super::{FulfillmentContext, SelectionContext};
 
-use rustc_error_codes::*;
-
 /// Information pertinent to an overlapping impl error.
 #[derive(Debug)]
 pub struct OverlapError {
diff --git a/src/librustc/ty/query/plumbing.rs b/src/librustc/ty/query/plumbing.rs
index 84efbe21f10aa..117a38c655eaa 100644
--- a/src/librustc/ty/query/plumbing.rs
+++ b/src/librustc/ty/query/plumbing.rs
@@ -25,8 +25,6 @@ use std::hash::{Hash, Hasher};
 use std::mem;
 use std::ptr;
 
-use rustc_error_codes::*;
-
 pub struct QueryCache<'tcx, D: QueryConfig<'tcx> + ?Sized> {
     pub(super) results: FxHashMap<D::Key, QueryValue<D::Value>>,
     pub(super) active: FxHashMap<D::Key, QueryResult<'tcx>>,
diff --git a/src/librustc_ast_lowering/Cargo.toml b/src/librustc_ast_lowering/Cargo.toml
index 408e9a75d93dd..4b786d6245fc4 100644
--- a/src/librustc_ast_lowering/Cargo.toml
+++ b/src/librustc_ast_lowering/Cargo.toml
@@ -17,7 +17,6 @@ rustc_target = { path = "../librustc_target" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_index = { path = "../librustc_index" }
 rustc_span = { path = "../librustc_span" }
-rustc_error_codes = { path = "../librustc_error_codes" }
 rustc_errors = { path = "../librustc_errors" }
 rustc_session = { path = "../librustc_session" }
 syntax = { path = "../libsyntax" }
diff --git a/src/librustc_ast_lowering/expr.rs b/src/librustc_ast_lowering/expr.rs
index 2866a1624de5b..a24bb52150a72 100644
--- a/src/librustc_ast_lowering/expr.rs
+++ b/src/librustc_ast_lowering/expr.rs
@@ -2,7 +2,6 @@ use super::{ImplTraitContext, LoweringContext, ParamMode, ParenthesizedGenericAr
 
 use rustc::bug;
 use rustc_data_structures::thin_vec::ThinVec;
-use rustc_error_codes::*;
 use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_hir::def::Res;
diff --git a/src/librustc_ast_lowering/item.rs b/src/librustc_ast_lowering/item.rs
index 6da2d457f3c3b..bcc40b0c9c9c9 100644
--- a/src/librustc_ast_lowering/item.rs
+++ b/src/librustc_ast_lowering/item.rs
@@ -3,7 +3,6 @@ use super::{ImplTraitContext, ImplTraitPosition, ImplTraitTypeIdVisitor};
 
 use rustc::arena::Arena;
 use rustc::bug;
-use rustc_error_codes::*;
 use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
diff --git a/src/librustc_ast_lowering/lib.rs b/src/librustc_ast_lowering/lib.rs
index 76a0889c376a2..2cd4a6eb7e21b 100644
--- a/src/librustc_ast_lowering/lib.rs
+++ b/src/librustc_ast_lowering/lib.rs
@@ -41,7 +41,6 @@ use rustc::{bug, span_bug};
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::sync::Lrc;
-use rustc_error_codes::*;
 use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Namespace, PartialRes, PerNS, Res};
diff --git a/src/librustc_ast_lowering/path.rs b/src/librustc_ast_lowering/path.rs
index 65347d379bd6a..e5f7df6dbf9e4 100644
--- a/src/librustc_ast_lowering/path.rs
+++ b/src/librustc_ast_lowering/path.rs
@@ -3,7 +3,6 @@ use super::{GenericArgsCtor, ParenthesizedGenericArgs};
 
 use rustc::lint::builtin::ELIDED_LIFETIMES_IN_PATHS;
 use rustc::span_bug;
-use rustc_error_codes::*;
 use rustc_errors::{struct_span_err, Applicability};
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, PartialRes, Res};
diff --git a/src/librustc_ast_passes/Cargo.toml b/src/librustc_ast_passes/Cargo.toml
index 2d45e28044495..25b1acebd2a08 100644
--- a/src/librustc_ast_passes/Cargo.toml
+++ b/src/librustc_ast_passes/Cargo.toml
@@ -12,7 +12,6 @@ path = "lib.rs"
 log = "0.4"
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_errors = { path = "../librustc_errors" }
-rustc_error_codes = { path = "../librustc_error_codes" }
 rustc_feature = { path = "../librustc_feature" }
 rustc_parse = { path = "../librustc_parse" }
 rustc_session = { path = "../librustc_session" }
diff --git a/src/librustc_ast_passes/ast_validation.rs b/src/librustc_ast_passes/ast_validation.rs
index 23701459025ae..bc02406aa2158 100644
--- a/src/librustc_ast_passes/ast_validation.rs
+++ b/src/librustc_ast_passes/ast_validation.rs
@@ -23,8 +23,6 @@ use syntax::print::pprust;
 use syntax::visit::{self, Visitor};
 use syntax::walk_list;
 
-use rustc_error_codes::*;
-
 /// A syntactic context that disallows certain kinds of bounds (e.g., `?Trait` or `?const Trait`).
 #[derive(Clone, Copy)]
 enum BoundContext {
diff --git a/src/librustc_ast_passes/feature_gate.rs b/src/librustc_ast_passes/feature_gate.rs
index 71cd66ddef409..d3f7eaa1fe3b8 100644
--- a/src/librustc_ast_passes/feature_gate.rs
+++ b/src/librustc_ast_passes/feature_gate.rs
@@ -1,4 +1,3 @@
-use rustc_error_codes::*;
 use rustc_errors::{struct_span_err, Handler};
 use rustc_feature::{AttributeGate, BUILTIN_ATTRIBUTE_MAP};
 use rustc_feature::{Features, GateIssue, UnstableFeatures};
diff --git a/src/librustc_builtin_macros/Cargo.toml b/src/librustc_builtin_macros/Cargo.toml
index f291eaf93580b..3ce7f5d770ed1 100644
--- a/src/librustc_builtin_macros/Cargo.toml
+++ b/src/librustc_builtin_macros/Cargo.toml
@@ -22,4 +22,3 @@ smallvec = { version = "1.0", features = ["union", "may_dangle"] }
 syntax = { path = "../libsyntax" }
 rustc_expand = { path = "../librustc_expand" }
 rustc_span = { path = "../librustc_span" }
-rustc_error_codes = { path = "../librustc_error_codes" }
diff --git a/src/librustc_builtin_macros/asm.rs b/src/librustc_builtin_macros/asm.rs
index a6b45e0567c72..4723544316faf 100644
--- a/src/librustc_builtin_macros/asm.rs
+++ b/src/librustc_builtin_macros/asm.rs
@@ -12,8 +12,6 @@ use syntax::ptr::P;
 use syntax::token::{self, Token};
 use syntax::tokenstream::{self, TokenStream};
 
-use rustc_error_codes::*;
-
 enum State {
     Asm,
     Outputs,
diff --git a/src/librustc_builtin_macros/deriving/default.rs b/src/librustc_builtin_macros/deriving/default.rs
index 72c41ad9745c1..b4f059e94c15e 100644
--- a/src/librustc_builtin_macros/deriving/default.rs
+++ b/src/librustc_builtin_macros/deriving/default.rs
@@ -9,8 +9,6 @@ use rustc_span::Span;
 use syntax::ast::{Expr, MetaItem};
 use syntax::ptr::P;
 
-use rustc_error_codes::*;
-
 pub fn expand_deriving_default(
     cx: &mut ExtCtxt<'_>,
     span: Span,
diff --git a/src/librustc_codegen_ssa/Cargo.toml b/src/librustc_codegen_ssa/Cargo.toml
index eb192b27405e9..9f8b4e72a9cbf 100644
--- a/src/librustc_codegen_ssa/Cargo.toml
+++ b/src/librustc_codegen_ssa/Cargo.toml
@@ -32,5 +32,4 @@ rustc_hir = { path = "../librustc_hir" }
 rustc_incremental = { path = "../librustc_incremental" }
 rustc_index = { path = "../librustc_index" }
 rustc_target = { path = "../librustc_target" }
-rustc_error_codes = { path = "../librustc_error_codes" }
 rustc_session = { path = "../librustc_session" }
diff --git a/src/librustc_codegen_ssa/common.rs b/src/librustc_codegen_ssa/common.rs
index e4531a77656a3..28b61e0b36d64 100644
--- a/src/librustc_codegen_ssa/common.rs
+++ b/src/librustc_codegen_ssa/common.rs
@@ -13,8 +13,6 @@ use rustc_hir::def_id::DefId;
 use crate::traits::BuilderMethods;
 use rustc_hir as hir;
 
-use rustc_error_codes::*;
-
 pub enum IntPredicate {
     IntEQ,
     IntNE,
diff --git a/src/librustc_codegen_ssa/mir/statement.rs b/src/librustc_codegen_ssa/mir/statement.rs
index 574c06d9ceb41..8422c625d634e 100644
--- a/src/librustc_codegen_ssa/mir/statement.rs
+++ b/src/librustc_codegen_ssa/mir/statement.rs
@@ -7,8 +7,6 @@ use super::OperandValue;
 use crate::traits::BuilderMethods;
 use crate::traits::*;
 
-use rustc_error_codes::*;
-
 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     pub fn codegen_statement(&mut self, mut bx: Bx, statement: &mir::Statement<'tcx>) -> Bx {
         debug!("codegen_statement(statement={:?})", statement);
diff --git a/src/librustc_error_codes/lib.rs b/src/librustc_error_codes/lib.rs
index 14210fd69ad51..f051fdd11b807 100644
--- a/src/librustc_error_codes/lib.rs
+++ b/src/librustc_error_codes/lib.rs
@@ -6,16 +6,8 @@ macro_rules! register_diagnostics {
         pub static DIAGNOSTICS: &[(&str, &str)] = &[
             $( (stringify!($ecode), $message), )*
         ];
-
-        $(
-            pub const $ecode: () = ();
-        )*
-        $(
-            pub const $code: () = ();
-        )*
     )
 }
 
 mod error_codes;
-
-pub use error_codes::*;
+pub use error_codes::DIAGNOSTICS;
diff --git a/src/librustc_errors/diagnostic_builder.rs b/src/librustc_errors/diagnostic_builder.rs
index 73f66d5503740..3c217c1d64373 100644
--- a/src/librustc_errors/diagnostic_builder.rs
+++ b/src/librustc_errors/diagnostic_builder.rs
@@ -399,8 +399,5 @@ macro_rules! struct_span_err {
 
 #[macro_export]
 macro_rules! error_code {
-    ($code:ident) => {{
-        let _ = $code;
-        $crate::DiagnosticId::Error(stringify!($code).to_owned())
-    }};
+    ($code:ident) => {{ $crate::DiagnosticId::Error(stringify!($code).to_owned()) }};
 }
diff --git a/src/librustc_lint/Cargo.toml b/src/librustc_lint/Cargo.toml
index abf9f96e6475b..7e23e70577975 100644
--- a/src/librustc_lint/Cargo.toml
+++ b/src/librustc_lint/Cargo.toml
@@ -13,7 +13,6 @@ log = "0.4"
 unicode-security = "0.0.2"
 rustc = { path = "../librustc" }
 rustc_errors = { path = "../librustc_errors" }
-rustc_error_codes = { path = "../librustc_error_codes" }
 rustc_hir = { path = "../librustc_hir" }
 rustc_target = { path = "../librustc_target" }
 syntax = { path = "../libsyntax" }
diff --git a/src/librustc_lint/context.rs b/src/librustc_lint/context.rs
index 42ec8787cb287..3b8cce5635d07 100644
--- a/src/librustc_lint/context.rs
+++ b/src/librustc_lint/context.rs
@@ -26,7 +26,6 @@ use rustc::ty::layout::{LayoutError, LayoutOf, TyLayout};
 use rustc::ty::{self, print::Printer, subst::GenericArg, Ty, TyCtxt};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync;
-use rustc_error_codes::*;
 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
 use rustc_hir as hir;
 use rustc_hir::def_id::{CrateNum, DefId};
diff --git a/src/librustc_lint/levels.rs b/src/librustc_lint/levels.rs
index bbc3e57f5dd01..d5bbdc53160f6 100644
--- a/src/librustc_lint/levels.rs
+++ b/src/librustc_lint/levels.rs
@@ -6,7 +6,6 @@ use rustc::lint::{LintLevelMap, LintLevelSets, LintSet, LintSource};
 use rustc::ty::query::Providers;
 use rustc::ty::TyCtxt;
 use rustc_data_structures::fx::FxHashMap;
-use rustc_error_codes::*;
 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
 use rustc_hir as hir;
 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
diff --git a/src/librustc_metadata/Cargo.toml b/src/librustc_metadata/Cargo.toml
index 0a0bcb190bea7..6da584733aea0 100644
--- a/src/librustc_metadata/Cargo.toml
+++ b/src/librustc_metadata/Cargo.toml
@@ -26,7 +26,6 @@ syntax = { path = "../libsyntax" }
 rustc_expand = { path = "../librustc_expand" }
 rustc_parse = { path = "../librustc_parse" }
 rustc_span = { path = "../librustc_span" }
-rustc_error_codes = { path = "../librustc_error_codes" }
 
 [target.'cfg(windows)'.dependencies]
 winapi = { version = "0.3", features = ["errhandlingapi", "libloaderapi"] }
diff --git a/src/librustc_metadata/creader.rs b/src/librustc_metadata/creader.rs
index 181f872154c51..351e72d4678f2 100644
--- a/src/librustc_metadata/creader.rs
+++ b/src/librustc_metadata/creader.rs
@@ -12,7 +12,6 @@ use rustc::session::{CrateDisambiguator, Session};
 use rustc::ty::TyCtxt;
 use rustc_data_structures::svh::Svh;
 use rustc_data_structures::sync::Lrc;
-use rustc_error_codes::*;
 use rustc_errors::struct_span_err;
 use rustc_expand::base::SyntaxExtension;
 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
diff --git a/src/librustc_metadata/locator.rs b/src/librustc_metadata/locator.rs
index 4745ad02a3aa4..578216454f9dc 100644
--- a/src/librustc_metadata/locator.rs
+++ b/src/librustc_metadata/locator.rs
@@ -241,8 +241,6 @@ use rustc_data_structures::owning_ref::OwningRef;
 
 use log::{debug, info, warn};
 
-use rustc_error_codes::*;
-
 #[derive(Clone)]
 struct CrateMismatch {
     path: PathBuf,
diff --git a/src/librustc_metadata/native_libs.rs b/src/librustc_metadata/native_libs.rs
index 9426d5e26f5e5..bbf6973be51a7 100644
--- a/src/librustc_metadata/native_libs.rs
+++ b/src/librustc_metadata/native_libs.rs
@@ -3,7 +3,6 @@ use rustc::session::parse::feature_err;
 use rustc::session::Session;
 use rustc::ty::TyCtxt;
 use rustc_data_structures::fx::FxHashSet;
-use rustc_error_codes::*;
 use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
diff --git a/src/librustc_mir/Cargo.toml b/src/librustc_mir/Cargo.toml
index f9b61b9e2c9d8..00881e3ea6f19 100644
--- a/src/librustc_mir/Cargo.toml
+++ b/src/librustc_mir/Cargo.toml
@@ -29,4 +29,3 @@ syntax = { path = "../libsyntax" }
 rustc_span = { path = "../librustc_span" }
 rustc_apfloat = { path = "../librustc_apfloat" }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
-rustc_error_codes = { path = "../librustc_error_codes" }
diff --git a/src/librustc_mir/borrow_check/type_check/mod.rs b/src/librustc_mir/borrow_check/type_check/mod.rs
index 947bbef4379f5..a92abc98cf4c1 100644
--- a/src/librustc_mir/borrow_check/type_check/mod.rs
+++ b/src/librustc_mir/borrow_check/type_check/mod.rs
@@ -27,7 +27,6 @@ use rustc::ty::{
     TyCtxt, UserType, UserTypeAnnotationIndex,
 };
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
-use rustc_error_codes::*;
 use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
diff --git a/src/librustc_mir/transform/check_consts/ops.rs b/src/librustc_mir/transform/check_consts/ops.rs
index edb4eb4d7c344..3263905eadb81 100644
--- a/src/librustc_mir/transform/check_consts/ops.rs
+++ b/src/librustc_mir/transform/check_consts/ops.rs
@@ -10,8 +10,6 @@ use rustc_span::{Span, Symbol};
 
 use super::{ConstKind, Item};
 
-use rustc_error_codes::*;
-
 /// An operation that is not *always* allowed in a const context.
 pub trait NonConstOp: std::fmt::Debug {
     /// Whether this operation can be evaluated by miri.
diff --git a/src/librustc_mir/transform/check_consts/validation.rs b/src/librustc_mir/transform/check_consts/validation.rs
index 10a4b7d92b764..1d5fb33ee8e81 100644
--- a/src/librustc_mir/transform/check_consts/validation.rs
+++ b/src/librustc_mir/transform/check_consts/validation.rs
@@ -6,7 +6,6 @@ use rustc::mir::*;
 use rustc::traits::{self, TraitEngine};
 use rustc::ty::cast::CastTy;
 use rustc::ty::{self, TyCtxt};
-use rustc_error_codes::*;
 use rustc_errors::struct_span_err;
 use rustc_hir::{def_id::DefId, HirId};
 use rustc_index::bit_set::BitSet;
diff --git a/src/librustc_mir/transform/check_unsafety.rs b/src/librustc_mir/transform/check_unsafety.rs
index 072cdf2ebba3a..4e943547f07f5 100644
--- a/src/librustc_mir/transform/check_unsafety.rs
+++ b/src/librustc_mir/transform/check_unsafety.rs
@@ -18,8 +18,6 @@ use std::ops::Bound;
 use crate::const_eval::{is_const_fn, is_min_const_fn};
 use crate::util;
 
-use rustc_error_codes::*;
-
 pub struct UnsafetyChecker<'a, 'tcx> {
     body: &'a Body<'tcx>,
     const_context: bool,
diff --git a/src/librustc_mir/util/borrowck_errors.rs b/src/librustc_mir/util/borrowck_errors.rs
index c275eecfb33b6..d8ee059f1a6b6 100644
--- a/src/librustc_mir/util/borrowck_errors.rs
+++ b/src/librustc_mir/util/borrowck_errors.rs
@@ -1,5 +1,4 @@
 use rustc::ty::{self, Ty, TyCtxt};
-use rustc_error_codes::*;
 use rustc_errors::{struct_span_err, DiagnosticBuilder, DiagnosticId};
 use rustc_span::{MultiSpan, Span};
 
diff --git a/src/librustc_mir_build/Cargo.toml b/src/librustc_mir_build/Cargo.toml
index 79c7303275597..f0d1d4c6515ce 100644
--- a/src/librustc_mir_build/Cargo.toml
+++ b/src/librustc_mir_build/Cargo.toml
@@ -25,4 +25,3 @@ rustc_span = { path = "../librustc_span" }
 rustc_target = { path = "../librustc_target" }
 syntax = { path = "../libsyntax" }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
-rustc_error_codes = { path = "../librustc_error_codes" }
diff --git a/src/librustc_mir_build/hair/pattern/check_match.rs b/src/librustc_mir_build/hair/pattern/check_match.rs
index 84d57a89c983e..eac52da7ba4ae 100644
--- a/src/librustc_mir_build/hair/pattern/check_match.rs
+++ b/src/librustc_mir_build/hair/pattern/check_match.rs
@@ -9,7 +9,6 @@ use rustc::lint;
 use rustc::session::parse::feature_err;
 use rustc::session::Session;
 use rustc::ty::{self, Ty, TyCtxt};
-use rustc_error_codes::*;
 use rustc_errors::{error_code, struct_span_err, Applicability, DiagnosticBuilder};
 use rustc_hir as hir;
 use rustc_hir::def::*;
diff --git a/src/librustc_mir_build/hair/pattern/mod.rs b/src/librustc_mir_build/hair/pattern/mod.rs
index 205e25f7f8f0c..2657050583071 100644
--- a/src/librustc_mir_build/hair/pattern/mod.rs
+++ b/src/librustc_mir_build/hair/pattern/mod.rs
@@ -28,8 +28,6 @@ use syntax::ast;
 use std::cmp::Ordering;
 use std::fmt;
 
-use rustc_error_codes::*;
-
 #[derive(Clone, Debug)]
 crate enum PatternError {
     AssocConstInPattern(Span),
diff --git a/src/librustc_parse/Cargo.toml b/src/librustc_parse/Cargo.toml
index aa159c55ff284..8071bc6312b36 100644
--- a/src/librustc_parse/Cargo.toml
+++ b/src/librustc_parse/Cargo.toml
@@ -16,7 +16,6 @@ rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_feature = { path = "../librustc_feature" }
 rustc_lexer = { path = "../librustc_lexer" }
 rustc_errors = { path = "../librustc_errors" }
-rustc_error_codes = { path = "../librustc_error_codes" }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
 rustc_session = { path = "../librustc_session" }
 rustc_span = { path = "../librustc_span" }
diff --git a/src/librustc_parse/config.rs b/src/librustc_parse/config.rs
index 8467acc759c2b..bf696faf2f3f4 100644
--- a/src/librustc_parse/config.rs
+++ b/src/librustc_parse/config.rs
@@ -10,7 +10,6 @@
 
 use crate::{parse_in, validate_attr};
 use rustc_data_structures::fx::FxHashMap;
-use rustc_error_codes::*;
 use rustc_errors::{error_code, struct_span_err, Applicability, Handler};
 use rustc_feature::{Feature, Features, State as FeatureState};
 use rustc_feature::{
diff --git a/src/librustc_parse/parser/diagnostics.rs b/src/librustc_parse/parser/diagnostics.rs
index 6a18c63017ed6..80bc5c158a64f 100644
--- a/src/librustc_parse/parser/diagnostics.rs
+++ b/src/librustc_parse/parser/diagnostics.rs
@@ -1,7 +1,6 @@
 use super::{BlockMode, Parser, PathStyle, SemiColonMode, SeqSep, TokenExpectType, TokenType};
 
 use rustc_data_structures::fx::FxHashSet;
-use rustc_error_codes::*;
 use rustc_errors::{pluralize, struct_span_err};
 use rustc_errors::{Applicability, DiagnosticBuilder, Handler, PResult};
 use rustc_span::source_map::Spanned;
diff --git a/src/librustc_parse/parser/item.rs b/src/librustc_parse/parser/item.rs
index 1921a6c850689..5076aafe4ebd5 100644
--- a/src/librustc_parse/parser/item.rs
+++ b/src/librustc_parse/parser/item.rs
@@ -3,7 +3,6 @@ use super::{FollowedByType, Parser, PathStyle};
 
 use crate::maybe_whole;
 
-use rustc_error_codes::*;
 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder, PResult, StashKey};
 use rustc_span::source_map::{self, respan, Span, Spanned};
 use rustc_span::symbol::{kw, sym, Symbol};
diff --git a/src/librustc_parse/parser/mod.rs b/src/librustc_parse/parser/mod.rs
index 1368230168e07..4a9016394d258 100644
--- a/src/librustc_parse/parser/mod.rs
+++ b/src/librustc_parse/parser/mod.rs
@@ -33,8 +33,6 @@ use std::borrow::Cow;
 use std::path::PathBuf;
 use std::{cmp, mem, slice};
 
-use rustc_error_codes::*;
-
 bitflags::bitflags! {
     struct Restrictions: u8 {
         const STMT_EXPR         = 1 << 0;
diff --git a/src/librustc_parse/parser/pat.rs b/src/librustc_parse/parser/pat.rs
index 549acf67d3824..edb9044df9206 100644
--- a/src/librustc_parse/parser/pat.rs
+++ b/src/librustc_parse/parser/pat.rs
@@ -659,7 +659,6 @@ impl<'a> Parser<'a> {
     }
 
     pub(super) fn error_inclusive_range_with_no_end(&self, span: Span) {
-        use rustc_error_codes::E0586;
         struct_span_err!(self.sess.span_diagnostic, span, E0586, "inclusive range with no end")
             .span_suggestion_short(
                 span,
diff --git a/src/librustc_parse/parser/ty.rs b/src/librustc_parse/parser/ty.rs
index 065a3b14428c7..d1875a6c940b1 100644
--- a/src/librustc_parse/parser/ty.rs
+++ b/src/librustc_parse/parser/ty.rs
@@ -3,7 +3,6 @@ use super::{Parser, PathStyle, PrevTokenKind, TokenType};
 
 use crate::{maybe_recover_from_interpolated_ty_qpath, maybe_whole};
 
-use rustc_error_codes::*;
 use rustc_errors::{pluralize, struct_span_err, Applicability, PResult};
 use rustc_span::source_map::Span;
 use rustc_span::symbol::{kw, sym};
diff --git a/src/librustc_passes/Cargo.toml b/src/librustc_passes/Cargo.toml
index 639d8639c4bb2..338808f6d4a0f 100644
--- a/src/librustc_passes/Cargo.toml
+++ b/src/librustc_passes/Cargo.toml
@@ -20,4 +20,3 @@ rustc_session = { path = "../librustc_session" }
 rustc_target = { path = "../librustc_target" }
 syntax = { path = "../libsyntax" }
 rustc_span = { path = "../librustc_span" }
-rustc_error_codes = { path = "../librustc_error_codes" }
diff --git a/src/librustc_passes/check_const.rs b/src/librustc_passes/check_const.rs
index 39ba2fbc63b43..faa85f68fab86 100644
--- a/src/librustc_passes/check_const.rs
+++ b/src/librustc_passes/check_const.rs
@@ -12,7 +12,6 @@ use rustc::session::config::nightly_options;
 use rustc::session::parse::feature_err;
 use rustc::ty::query::Providers;
 use rustc::ty::TyCtxt;
-use rustc_error_codes::*;
 use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
diff --git a/src/librustc_passes/entry.rs b/src/librustc_passes/entry.rs
index 028d7c662758a..d36114fd3b5b5 100644
--- a/src/librustc_passes/entry.rs
+++ b/src/librustc_passes/entry.rs
@@ -12,8 +12,6 @@ use rustc_span::{Span, DUMMY_SP};
 use syntax::attr;
 use syntax::entry::EntryPointType;
 
-use rustc_error_codes::*;
-
 struct EntryContext<'a, 'tcx> {
     session: &'a Session,
 
diff --git a/src/librustc_passes/intrinsicck.rs b/src/librustc_passes/intrinsicck.rs
index 2c26707a51850..782199003c72a 100644
--- a/src/librustc_passes/intrinsicck.rs
+++ b/src/librustc_passes/intrinsicck.rs
@@ -11,8 +11,6 @@ use rustc_index::vec::Idx;
 use rustc_span::{sym, Span};
 use rustc_target::spec::abi::Abi::RustIntrinsic;
 
-use rustc_error_codes::*;
-
 fn check_mod_intrinsics(tcx: TyCtxt<'_>, module_def_id: DefId) {
     tcx.hir().visit_item_likes_in_module(module_def_id, &mut ItemVisitor { tcx }.as_deep_visitor());
 }
diff --git a/src/librustc_passes/lib_features.rs b/src/librustc_passes/lib_features.rs
index 8ae7291289786..2e306a1b4f2a1 100644
--- a/src/librustc_passes/lib_features.rs
+++ b/src/librustc_passes/lib_features.rs
@@ -15,8 +15,6 @@ use rustc_span::symbol::Symbol;
 use rustc_span::{sym, Span};
 use syntax::ast::{Attribute, MetaItem, MetaItemKind};
 
-use rustc_error_codes::*;
-
 fn new_lib_features() -> LibFeatures {
     LibFeatures { stable: Default::default(), unstable: Default::default() }
 }
diff --git a/src/librustc_passes/loops.rs b/src/librustc_passes/loops.rs
index 5ad5795c777d4..69d6b38005c4c 100644
--- a/src/librustc_passes/loops.rs
+++ b/src/librustc_passes/loops.rs
@@ -1,7 +1,5 @@
 use Context::*;
 
-use rustc::session::Session;
-
 use rustc::hir::map::Map;
 use rustc::ty::query::Providers;
 use rustc::ty::TyCtxt;
@@ -10,10 +8,9 @@ use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
 use rustc_hir::{Destination, Movability, Node};
+use rustc_session::Session;
 use rustc_span::Span;
 
-use rustc_error_codes::*;
-
 #[derive(Clone, Copy, Debug, PartialEq)]
 enum Context {
     Normal,
diff --git a/src/librustc_passes/stability.rs b/src/librustc_passes/stability.rs
index b649f36f2fc58..320b433190e5e 100644
--- a/src/librustc_passes/stability.rs
+++ b/src/librustc_passes/stability.rs
@@ -26,8 +26,6 @@ use std::cmp::Ordering;
 use std::mem::replace;
 use std::num::NonZeroU32;
 
-use rustc_error_codes::*;
-
 #[derive(PartialEq)]
 enum AnnotationKind {
     // Annotation is required if not inherited from unstable parents
diff --git a/src/librustc_plugin_impl/Cargo.toml b/src/librustc_plugin_impl/Cargo.toml
index 41e6c699c340e..2214838c84683 100644
--- a/src/librustc_plugin_impl/Cargo.toml
+++ b/src/librustc_plugin_impl/Cargo.toml
@@ -18,4 +18,3 @@ rustc_lint = { path = "../librustc_lint" }
 rustc_metadata = { path = "../librustc_metadata" }
 syntax = { path = "../libsyntax" }
 rustc_span = { path = "../librustc_span" }
-rustc_error_codes = { path = "../librustc_error_codes" }
diff --git a/src/librustc_plugin_impl/load.rs b/src/librustc_plugin_impl/load.rs
index 65661ec24f07f..84549c0dd4554 100644
--- a/src/librustc_plugin_impl/load.rs
+++ b/src/librustc_plugin_impl/load.rs
@@ -3,7 +3,6 @@
 use crate::Registry;
 use rustc::middle::cstore::MetadataLoader;
 use rustc::session::Session;
-use rustc_error_codes::*;
 use rustc_errors::struct_span_err;
 use rustc_metadata::locator;
 use rustc_span::symbol::sym;
diff --git a/src/librustc_privacy/Cargo.toml b/src/librustc_privacy/Cargo.toml
index 795b6c107fe94..4f341b545156c 100644
--- a/src/librustc_privacy/Cargo.toml
+++ b/src/librustc_privacy/Cargo.toml
@@ -16,5 +16,4 @@ rustc_typeck = { path = "../librustc_typeck" }
 syntax = { path = "../libsyntax" }
 rustc_span = { path = "../librustc_span" }
 rustc_data_structures = { path = "../librustc_data_structures" }
-rustc_error_codes = { path = "../librustc_error_codes" }
 log = "0.4"
diff --git a/src/librustc_privacy/lib.rs b/src/librustc_privacy/lib.rs
index 90a422a4dcf6c..634905450d4ed 100644
--- a/src/librustc_privacy/lib.rs
+++ b/src/librustc_privacy/lib.rs
@@ -27,8 +27,6 @@ use syntax::attr;
 use std::marker::PhantomData;
 use std::{cmp, fmt, mem};
 
-use rustc_error_codes::*;
-
 ////////////////////////////////////////////////////////////////////////////////
 /// Generic infrastructure used to implement specific visitors below.
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/src/librustc_resolve/Cargo.toml b/src/librustc_resolve/Cargo.toml
index af37e7b5b76ac..c4cc6b09c736e 100644
--- a/src/librustc_resolve/Cargo.toml
+++ b/src/librustc_resolve/Cargo.toml
@@ -23,7 +23,6 @@ rustc_expand = { path = "../librustc_expand" }
 rustc_feature = { path = "../librustc_feature" }
 rustc_hir = { path = "../librustc_hir" }
 rustc_metadata = { path = "../librustc_metadata" }
-rustc_error_codes = { path = "../librustc_error_codes" }
 rustc_session = { path = "../librustc_session" }
 rustc_span = { path = "../librustc_span" }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
diff --git a/src/librustc_resolve/build_reduced_graph.rs b/src/librustc_resolve/build_reduced_graph.rs
index 40a89ef067458..7ff076268ab82 100644
--- a/src/librustc_resolve/build_reduced_graph.rs
+++ b/src/librustc_resolve/build_reduced_graph.rs
@@ -21,7 +21,6 @@ use rustc::hir::exports::Export;
 use rustc::middle::cstore::CrateStore;
 use rustc::ty;
 use rustc_data_structures::sync::Lrc;
-use rustc_error_codes::*;
 use rustc_errors::{struct_span_err, Applicability};
 use rustc_expand::base::SyntaxExtension;
 use rustc_expand::expand::AstFragment;
diff --git a/src/librustc_resolve/diagnostics.rs b/src/librustc_resolve/diagnostics.rs
index a433ae8ed676a..3d4384cabe204 100644
--- a/src/librustc_resolve/diagnostics.rs
+++ b/src/librustc_resolve/diagnostics.rs
@@ -25,8 +25,6 @@ use crate::{BindingError, CrateLint, HasGenericParams, LegacyScope, Module, Modu
 use crate::{NameBinding, NameBindingKind, PrivacyError, VisResolutionError};
 use crate::{ParentScope, PathResult, ResolutionError, Resolver, Scope, ScopeSet, Segment};
 
-use rustc_error_codes::*;
-
 type Res = def::Res<ast::NodeId>;
 
 /// A vector of spans and replacements, a message and applicability.
diff --git a/src/librustc_resolve/imports.rs b/src/librustc_resolve/imports.rs
index 9f459834175c1..55ce51e0ff057 100644
--- a/src/librustc_resolve/imports.rs
+++ b/src/librustc_resolve/imports.rs
@@ -29,8 +29,6 @@ use syntax::ast::{Ident, Name, NodeId};
 use syntax::unwrap_or;
 use syntax::util::lev_distance::find_best_match_for_name;
 
-use rustc_error_codes::*;
-
 use log::*;
 
 use std::cell::Cell;
diff --git a/src/librustc_resolve/late.rs b/src/librustc_resolve/late.rs
index 08cd9c4d1d53a..5e08ac8e2c38a 100644
--- a/src/librustc_resolve/late.rs
+++ b/src/librustc_resolve/late.rs
@@ -31,8 +31,6 @@ use log::debug;
 use std::collections::BTreeSet;
 use std::mem::replace;
 
-use rustc_error_codes::*;
-
 mod diagnostics;
 
 type Res = def::Res<NodeId>;
diff --git a/src/librustc_resolve/late/diagnostics.rs b/src/librustc_resolve/late/diagnostics.rs
index 151f3e834e5de..6a98c9e59a9ce 100644
--- a/src/librustc_resolve/late/diagnostics.rs
+++ b/src/librustc_resolve/late/diagnostics.rs
@@ -6,7 +6,6 @@ use crate::{PathResult, PathSource, Segment};
 
 use rustc::session::config::nightly_options;
 use rustc_data_structures::fx::FxHashSet;
-use rustc_error_codes::*;
 use rustc_errors::{Applicability, DiagnosticBuilder};
 use rustc_hir::def::Namespace::{self, *};
 use rustc_hir::def::{self, CtorKind, DefKind};
diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index 60a0049f5da37..5d132191f9208 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -61,8 +61,6 @@ use imports::{ImportDirective, ImportDirectiveSubclass, ImportResolver, NameReso
 use late::{HasGenericParams, PathSource, Rib, RibKind::*};
 use macros::{LegacyBinding, LegacyScope};
 
-use rustc_error_codes::*;
-
 type Res = def::Res<NodeId>;
 
 mod build_reduced_graph;
diff --git a/src/librustc_resolve/lifetimes.rs b/src/librustc_resolve/lifetimes.rs
index 5fae8f3318743..a2ca80cf5f30a 100644
--- a/src/librustc_resolve/lifetimes.rs
+++ b/src/librustc_resolve/lifetimes.rs
@@ -30,8 +30,6 @@ use syntax::walk_list;
 
 use log::debug;
 
-use rustc_error_codes::*;
-
 // This counts the no of times a lifetime is used
 #[derive(Clone, Copy, Debug)]
 pub enum LifetimeUseSet<'tcx> {
diff --git a/src/librustc_session/Cargo.toml b/src/librustc_session/Cargo.toml
index 377ea141ed57c..47c23bc4dcf98 100644
--- a/src/librustc_session/Cargo.toml
+++ b/src/librustc_session/Cargo.toml
@@ -10,7 +10,6 @@ path = "lib.rs"
 
 [dependencies]
 log = "0.4"
-rustc_error_codes = { path = "../librustc_error_codes" }
 rustc_errors = { path = "../librustc_errors" }
 rustc_feature = { path = "../librustc_feature" }
 rustc_target = { path = "../librustc_target" }
diff --git a/src/librustc_session/parse.rs b/src/librustc_session/parse.rs
index a98cf929095ea..72c68fcb244c9 100644
--- a/src/librustc_session/parse.rs
+++ b/src/librustc_session/parse.rs
@@ -6,7 +6,6 @@ use crate::node_id::NodeId;
 
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::sync::{Lock, Lrc, Once};
-use rustc_error_codes::E0658;
 use rustc_errors::{emitter::SilentEmitter, ColorConfig, Handler};
 use rustc_errors::{error_code, Applicability, DiagnosticBuilder};
 use rustc_feature::{find_feature_issue, GateIssue, UnstableFeatures};
diff --git a/src/librustc_typeck/Cargo.toml b/src/librustc_typeck/Cargo.toml
index 84e5f56d9c208..4b27d86dd02a7 100644
--- a/src/librustc_typeck/Cargo.toml
+++ b/src/librustc_typeck/Cargo.toml
@@ -22,4 +22,3 @@ smallvec = { version = "1.0", features = ["union", "may_dangle"] }
 syntax = { path = "../libsyntax" }
 rustc_span = { path = "../librustc_span" }
 rustc_index = { path = "../librustc_index" }
-rustc_error_codes = { path = "../librustc_error_codes" }
diff --git a/src/librustc_typeck/astconv.rs b/src/librustc_typeck/astconv.rs
index 173bb29e964d1..047c14cfbcff7 100644
--- a/src/librustc_typeck/astconv.rs
+++ b/src/librustc_typeck/astconv.rs
@@ -39,7 +39,6 @@ use std::iter;
 use std::slice;
 
 use rustc::mir::interpret::LitToConstInput;
-use rustc_error_codes::*;
 
 #[derive(Debug)]
 pub struct PathSeg(pub DefId, pub usize);
diff --git a/src/librustc_typeck/check/autoderef.rs b/src/librustc_typeck/check/autoderef.rs
index 8d6b74c3015c9..3ea5de9a8375d 100644
--- a/src/librustc_typeck/check/autoderef.rs
+++ b/src/librustc_typeck/check/autoderef.rs
@@ -13,8 +13,6 @@ use rustc_hir as hir;
 use rustc_span::Span;
 use syntax::ast::Ident;
 
-use rustc_error_codes::*;
-
 use std::iter;
 
 #[derive(Copy, Clone, Debug)]
diff --git a/src/librustc_typeck/check/callee.rs b/src/librustc_typeck/check/callee.rs
index 58f407b890278..b33cc52b238e3 100644
--- a/src/librustc_typeck/check/callee.rs
+++ b/src/librustc_typeck/check/callee.rs
@@ -8,7 +8,6 @@ use rustc::ty::adjustment::{Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoB
 use rustc::ty::subst::SubstsRef;
 use rustc::ty::{self, Ty, TyCtxt, TypeFoldable};
 use rustc::{infer, traits};
-use rustc_error_codes::*;
 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
 use rustc_hir as hir;
 use rustc_hir::def::Res;
diff --git a/src/librustc_typeck/check/cast.rs b/src/librustc_typeck/check/cast.rs
index cbbfe2d627895..d254a84df72ce 100644
--- a/src/librustc_typeck/check/cast.rs
+++ b/src/librustc_typeck/check/cast.rs
@@ -49,8 +49,6 @@ use rustc_hir as hir;
 use rustc_span::Span;
 use syntax::ast;
 
-use rustc_error_codes::*;
-
 /// Reifies a cast check to be checked once we have full type information for
 /// a function context.
 pub struct CastCheck<'tcx> {
diff --git a/src/librustc_typeck/check/coercion.rs b/src/librustc_typeck/check/coercion.rs
index a32fbff7bfe2d..8c8e0642dffce 100644
--- a/src/librustc_typeck/check/coercion.rs
+++ b/src/librustc_typeck/check/coercion.rs
@@ -65,7 +65,6 @@ use rustc::ty::fold::TypeFoldable;
 use rustc::ty::relate::RelateResult;
 use rustc::ty::subst::SubstsRef;
 use rustc::ty::{self, Ty, TypeAndMut};
-use rustc_error_codes::*;
 use rustc_errors::{struct_span_err, DiagnosticBuilder};
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
diff --git a/src/librustc_typeck/check/compare_method.rs b/src/librustc_typeck/check/compare_method.rs
index c35661ac649fc..414f80d84b672 100644
--- a/src/librustc_typeck/check/compare_method.rs
+++ b/src/librustc_typeck/check/compare_method.rs
@@ -15,8 +15,6 @@ use rustc_span::Span;
 
 use super::{potentially_plural_count, FnCtxt, Inherited};
 
-use rustc_error_codes::*;
-
 /// Checks that a method from an impl conforms to the signature of
 /// the same method as declared in the trait.
 ///
diff --git a/src/librustc_typeck/check/dropck.rs b/src/librustc_typeck/check/dropck.rs
index 88e7a265ebbcf..f4aa53a5a9389 100644
--- a/src/librustc_typeck/check/dropck.rs
+++ b/src/librustc_typeck/check/dropck.rs
@@ -14,8 +14,6 @@ use rustc_errors::struct_span_err;
 
 use rustc_span::Span;
 
-use rustc_error_codes::*;
-
 /// This function confirms that the `Drop` implementation identified by
 /// `drop_impl_did` is not any more specialized than the type it is
 /// attached to (Issue #8142).
diff --git a/src/librustc_typeck/check/expr.rs b/src/librustc_typeck/check/expr.rs
index 35342de59a082..201a09fdc63fa 100644
--- a/src/librustc_typeck/check/expr.rs
+++ b/src/librustc_typeck/check/expr.rs
@@ -38,8 +38,6 @@ use rustc_span::symbol::{kw, sym, Symbol};
 use syntax::ast;
 use syntax::util::lev_distance::find_best_match_for_name;
 
-use rustc_error_codes::*;
-
 use std::fmt::Display;
 
 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
diff --git a/src/librustc_typeck/check/intrinsic.rs b/src/librustc_typeck/check/intrinsic.rs
index 0441514c83c9d..3572eda5c1399 100644
--- a/src/librustc_typeck/check/intrinsic.rs
+++ b/src/librustc_typeck/check/intrinsic.rs
@@ -6,7 +6,6 @@ use crate::require_same_types;
 use rustc::traits::{ObligationCause, ObligationCauseCode};
 use rustc::ty::subst::Subst;
 use rustc::ty::{self, Ty, TyCtxt};
-use rustc_error_codes::*;
 use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_span::symbol::Symbol;
diff --git a/src/librustc_typeck/check/method/probe.rs b/src/librustc_typeck/check/method/probe.rs
index b2542cc27a551..9d8f57119ddde 100644
--- a/src/librustc_typeck/check/method/probe.rs
+++ b/src/librustc_typeck/check/method/probe.rs
@@ -38,8 +38,6 @@ use std::ops::Deref;
 use syntax::ast;
 use syntax::util::lev_distance::{find_best_match_for_name, lev_distance};
 
-use rustc_error_codes::*;
-
 use smallvec::{smallvec, SmallVec};
 
 use self::CandidateKind::*;
diff --git a/src/librustc_typeck/check/method/suggest.rs b/src/librustc_typeck/check/method/suggest.rs
index d6c0d9c77b495..88de2654cea54 100644
--- a/src/librustc_typeck/check/method/suggest.rs
+++ b/src/librustc_typeck/check/method/suggest.rs
@@ -21,8 +21,6 @@ use rustc_span::{source_map, FileName, Span};
 use syntax::ast;
 use syntax::util::lev_distance;
 
-use rustc_error_codes::*;
-
 use std::cmp::Ordering;
 
 use super::probe::Mode;
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 4affdc4a9d64e..f7df630fb90b1 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -133,8 +133,6 @@ use syntax::ast;
 use syntax::attr;
 use syntax::util::parser::ExprPrecedence;
 
-use rustc_error_codes::*;
-
 use std::cell::{Cell, Ref, RefCell, RefMut};
 use std::cmp;
 use std::collections::hash_map::Entry;
diff --git a/src/librustc_typeck/check/op.rs b/src/librustc_typeck/check/op.rs
index edf9d19dea377..91e1731ac458b 100644
--- a/src/librustc_typeck/check/op.rs
+++ b/src/librustc_typeck/check/op.rs
@@ -11,8 +11,6 @@ use rustc_hir as hir;
 use rustc_span::Span;
 use syntax::ast::Ident;
 
-use rustc_error_codes::*;
-
 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// Checks a `a <op>= b`
     pub fn check_binop_assign(
diff --git a/src/librustc_typeck/check/pat.rs b/src/librustc_typeck/check/pat.rs
index 1478b35a25ddc..f9dee0e477f79 100644
--- a/src/librustc_typeck/check/pat.rs
+++ b/src/librustc_typeck/check/pat.rs
@@ -15,8 +15,6 @@ use rustc_span::Span;
 use syntax::ast;
 use syntax::util::lev_distance::find_best_match_for_name;
 
-use rustc_error_codes::*;
-
 use std::cmp;
 use std::collections::hash_map::Entry::{Occupied, Vacant};
 
diff --git a/src/librustc_typeck/check/wfcheck.rs b/src/librustc_typeck/check/wfcheck.rs
index 5e91e98a7dfa5..910e680de69dc 100644
--- a/src/librustc_typeck/check/wfcheck.rs
+++ b/src/librustc_typeck/check/wfcheck.rs
@@ -18,8 +18,6 @@ use syntax::ast;
 use rustc_hir as hir;
 use rustc_hir::itemlikevisit::ParItemLikeVisitor;
 
-use rustc_error_codes::*;
-
 /// Helper type of a temporary returned by `.for_item(...)`.
 /// This is necessary because we can't write the following bound:
 ///
diff --git a/src/librustc_typeck/coherence/builtin.rs b/src/librustc_typeck/coherence/builtin.rs
index 516dc16d46bd8..79a006a898a89 100644
--- a/src/librustc_typeck/coherence/builtin.rs
+++ b/src/librustc_typeck/coherence/builtin.rs
@@ -12,7 +12,6 @@ use rustc::traits::{self, ObligationCause, TraitEngine};
 use rustc::ty::adjustment::CoerceUnsizedInfo;
 use rustc::ty::TypeFoldable;
 use rustc::ty::{self, Ty, TyCtxt};
-use rustc_error_codes::*;
 use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
diff --git a/src/librustc_typeck/coherence/inherent_impls.rs b/src/librustc_typeck/coherence/inherent_impls.rs
index d313e32fc20e0..d4c89b7e03793 100644
--- a/src/librustc_typeck/coherence/inherent_impls.rs
+++ b/src/librustc_typeck/coherence/inherent_impls.rs
@@ -16,8 +16,6 @@ use rustc_hir::itemlikevisit::ItemLikeVisitor;
 use rustc_span::Span;
 use syntax::ast;
 
-use rustc_error_codes::*;
-
 /// On-demand query: yields a map containing all types mapped to their inherent impls.
 pub fn crate_inherent_impls(tcx: TyCtxt<'_>, crate_num: CrateNum) -> &CrateInherentImpls {
     assert_eq!(crate_num, LOCAL_CRATE);
diff --git a/src/librustc_typeck/coherence/inherent_impls_overlap.rs b/src/librustc_typeck/coherence/inherent_impls_overlap.rs
index a9228c7f6bb4c..d60c3cfba9a5b 100644
--- a/src/librustc_typeck/coherence/inherent_impls_overlap.rs
+++ b/src/librustc_typeck/coherence/inherent_impls_overlap.rs
@@ -6,8 +6,6 @@ use rustc_hir as hir;
 use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
 
-use rustc_error_codes::*;
-
 pub fn crate_inherent_impls_overlap_check(tcx: TyCtxt<'_>, crate_num: CrateNum) {
     assert_eq!(crate_num, LOCAL_CRATE);
     let krate = tcx.hir().krate();
diff --git a/src/librustc_typeck/coherence/mod.rs b/src/librustc_typeck/coherence/mod.rs
index fd685e77b418c..5583e3418b2a8 100644
--- a/src/librustc_typeck/coherence/mod.rs
+++ b/src/librustc_typeck/coherence/mod.rs
@@ -8,7 +8,6 @@
 use rustc::traits;
 use rustc::ty::query::Providers;
 use rustc::ty::{self, TyCtxt, TypeFoldable};
-use rustc_error_codes::*;
 use rustc_errors::struct_span_err;
 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 use rustc_hir::HirId;
diff --git a/src/librustc_typeck/coherence/orphan.rs b/src/librustc_typeck/coherence/orphan.rs
index 9ba8fa4247f26..80521666476e6 100644
--- a/src/librustc_typeck/coherence/orphan.rs
+++ b/src/librustc_typeck/coherence/orphan.rs
@@ -7,8 +7,6 @@ use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
 
-use rustc_error_codes::*;
-
 pub fn check(tcx: TyCtxt<'_>) {
     let mut orphan = OrphanChecker { tcx };
     tcx.hir().krate().visit_all_item_likes(&mut orphan);
diff --git a/src/librustc_typeck/coherence/unsafety.rs b/src/librustc_typeck/coherence/unsafety.rs
index 48b96886d3a71..a604421740363 100644
--- a/src/librustc_typeck/coherence/unsafety.rs
+++ b/src/librustc_typeck/coherence/unsafety.rs
@@ -7,8 +7,6 @@ use rustc_hir as hir;
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
 use rustc_hir::Unsafety;
 
-use rustc_error_codes::*;
-
 pub fn check(tcx: TyCtxt<'_>) {
     let mut unsafety = UnsafetyChecker { tcx };
     tcx.hir().krate().visit_all_item_likes(&mut unsafety);
diff --git a/src/librustc_typeck/collect.rs b/src/librustc_typeck/collect.rs
index a03b9f747372e..9eee31c3a5763 100644
--- a/src/librustc_typeck/collect.rs
+++ b/src/librustc_typeck/collect.rs
@@ -47,8 +47,6 @@ use syntax::ast;
 use syntax::ast::{Ident, MetaItemKind};
 use syntax::attr::{list_contains_name, mark_used, InlineAttr, OptimizeAttr};
 
-use rustc_error_codes::*;
-
 struct OnlySelfBounds(bool);
 
 ///////////////////////////////////////////////////////////////////////////
diff --git a/src/librustc_typeck/impl_wf_check.rs b/src/librustc_typeck/impl_wf_check.rs
index 9ee4e7c48190d..e9c18b59da982 100644
--- a/src/librustc_typeck/impl_wf_check.rs
+++ b/src/librustc_typeck/impl_wf_check.rs
@@ -20,8 +20,6 @@ use std::collections::hash_map::Entry::{Occupied, Vacant};
 
 use rustc_span::Span;
 
-use rustc_error_codes::*;
-
 /// Checks that all the type/lifetime parameters on an impl also
 /// appear in the trait ref or self type (or are constrained by a
 /// where-clause). These rules are needed to ensure that, given a
diff --git a/src/librustc_typeck/lib.rs b/src/librustc_typeck/lib.rs
index b951883ac195a..de8e917d0b8c7 100644
--- a/src/librustc_typeck/lib.rs
+++ b/src/librustc_typeck/lib.rs
@@ -109,8 +109,6 @@ use rustc_hir::Node;
 use rustc_span::{Span, DUMMY_SP};
 use rustc_target::spec::abi::Abi;
 
-use rustc_error_codes::*;
-
 use std::iter;
 
 use astconv::{AstConv, Bounds};
diff --git a/src/librustc_typeck/outlives/test.rs b/src/librustc_typeck/outlives/test.rs
index 908429c8dc48a..980d58ad939d7 100644
--- a/src/librustc_typeck/outlives/test.rs
+++ b/src/librustc_typeck/outlives/test.rs
@@ -4,8 +4,6 @@ use rustc_hir as hir;
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
 use rustc_span::symbol::sym;
 
-use rustc_error_codes::*;
-
 pub fn test_inferred_outlives(tcx: TyCtxt<'_>) {
     tcx.hir().krate().visit_all_item_likes(&mut OutlivesTest { tcx });
 }
diff --git a/src/librustc_typeck/structured_errors.rs b/src/librustc_typeck/structured_errors.rs
index 068814723f52d..99b7b2001a9e9 100644
--- a/src/librustc_typeck/structured_errors.rs
+++ b/src/librustc_typeck/structured_errors.rs
@@ -3,8 +3,6 @@ use rustc::ty::{Ty, TypeFoldable};
 use rustc_errors::{Applicability, DiagnosticBuilder, DiagnosticId};
 use rustc_span::Span;
 
-use rustc_error_codes::*;
-
 pub trait StructuredDiagnostic<'tcx> {
     fn session(&self) -> &Session;
 
diff --git a/src/librustc_typeck/variance/test.rs b/src/librustc_typeck/variance/test.rs
index 2f41bee1819cd..ee94b1015a1f4 100644
--- a/src/librustc_typeck/variance/test.rs
+++ b/src/librustc_typeck/variance/test.rs
@@ -4,8 +4,6 @@ use rustc_hir as hir;
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
 use rustc_span::symbol::sym;
 
-use rustc_error_codes::*;
-
 pub fn test_variance(tcx: TyCtxt<'_>) {
     tcx.hir().krate().visit_all_item_likes(&mut VarianceTest { tcx });
 }
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 1da00e3a47b82..403c8d0160d8a 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -23,7 +23,6 @@ extern crate getopts;
 extern crate rustc;
 extern crate rustc_data_structures;
 extern crate rustc_driver;
-extern crate rustc_error_codes;
 extern crate rustc_errors;
 extern crate rustc_expand;
 extern crate rustc_feature;
diff --git a/src/libsyntax/Cargo.toml b/src/libsyntax/Cargo.toml
index 7d9f715e9feb8..2e647d2a1e081 100644
--- a/src/libsyntax/Cargo.toml
+++ b/src/libsyntax/Cargo.toml
@@ -21,5 +21,4 @@ rustc_index = { path = "../librustc_index" }
 rustc_lexer = { path = "../librustc_lexer" }
 rustc_macros = { path = "../librustc_macros" }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
-rustc_error_codes = { path = "../librustc_error_codes" }
 rustc_session = { path = "../librustc_session" }
diff --git a/src/libsyntax/attr/builtin.rs b/src/libsyntax/attr/builtin.rs
index 70f4f47621a34..6cfe4f2de1e96 100644
--- a/src/libsyntax/attr/builtin.rs
+++ b/src/libsyntax/attr/builtin.rs
@@ -12,8 +12,6 @@ use rustc_span::hygiene::Transparency;
 use rustc_span::{symbol::sym, symbol::Symbol, Span};
 use std::num::NonZeroU32;
 
-use rustc_error_codes::*;
-
 pub fn is_builtin_attr(attr: &Attribute) -> bool {
     attr.is_doc_comment() || attr.ident().filter(|ident| is_builtin_attr_name(ident.name)).is_some()
 }