Rollup merge of #70344 - Centril:hir-pretty, r=eddyb

Decouple `rustc_hir::print` into `rustc_hir_pretty`

High level summary:
- The HIR pretty printer, `rustc_hir::print` is moved into a new crate `rustc_hir_pretty`.
- `rustc_ast_pretty` and `rustc_errors` are dropped as `rustc_hir` dependencies.
- The dependence on HIR pretty is generally reduced, leaving `rustc_save_analysis`, `rustdoc`, `rustc_metadata`, and `rustc_driver` as the remaining clients.

The main goal here is to reduce `rustc_hir`'s dependencies and its size such that it can start and finish earlier, thereby working towards https://github.com/rust-lang/rust/issues/65031.

r? @Zoxc

37 files changed, 288 insertions, 313 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 8bf61989135..f1fa91362b1 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3668,6 +3668,7 @@ dependencies = [
  "rustc_errors",
  "rustc_feature",
  "rustc_hir",
+ "rustc_hir_pretty",
  "rustc_interface",
  "rustc_lint",
  "rustc_metadata",
@@ -3742,9 +3743,7 @@ dependencies = [
  "lazy_static 1.4.0",
  "log",
  "rustc_ast",
- "rustc_ast_pretty",
  "rustc_data_structures",
- "rustc_errors",
  "rustc_index",
  "rustc_macros",
  "rustc_span",
@@ -3754,6 +3753,18 @@ dependencies = [
 ]
 
 [[package]]
+name = "rustc_hir_pretty"
+version = "0.0.0"
+dependencies = [
+ "rustc_ast",
+ "rustc_ast_pretty",
+ "rustc_data_structures",
+ "rustc_hir",
+ "rustc_span",
+ "rustc_target",
+]
+
+[[package]]
 name = "rustc_incremental"
 version = "0.0.0"
 dependencies = [
@@ -3903,6 +3914,7 @@ dependencies = [
  "rustc_errors",
  "rustc_expand",
  "rustc_hir",
+ "rustc_hir_pretty",
  "rustc_index",
  "rustc_session",
  "rustc_span",
@@ -4087,6 +4099,7 @@ dependencies = [
  "rustc_ast_pretty",
  "rustc_data_structures",
  "rustc_hir",
+ "rustc_hir_pretty",
  "rustc_parse",
  "rustc_session",
  "rustc_span",
diff --git a/src/librustc/hir/map/mod.rs b/src/librustc/hir/map/mod.rs
index 6290f5bb9b4..bc42ac1f0d7 100644
--- a/src/librustc/hir/map/mod.rs
+++ b/src/librustc/hir/map/mod.rs
@@ -10,7 +10,6 @@ use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LOCAL_CRATE};
 use rustc_hir::definitions::{DefKey, DefPath, Definitions};
 use rustc_hir::intravisit;
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
-use rustc_hir::print::Nested;
 use rustc_hir::*;
 use rustc_index::vec::IndexVec;
 use rustc_span::hygiene::MacroKind;
@@ -890,20 +889,18 @@ impl<'hir> Map<'hir> {
         }
     }
 
+    /// Get a representation of this `id` for debugging purposes.
+    /// NOTE: Do NOT use this in diagnostics!
     pub fn node_to_string(&self, id: HirId) -> String {
-        hir_id_to_string(self, id, true)
-    }
-
-    pub fn hir_to_user_string(&self, id: HirId) -> String {
-        hir_id_to_string(self, id, false)
-    }
-
-    pub fn hir_to_pretty_string(&self, id: HirId) -> String {
-        print::to_string(self, |s| s.print_node(self.get(id)))
+        hir_id_to_string(self, id)
     }
 }
 
 impl<'hir> intravisit::Map<'hir> for Map<'hir> {
+    fn find(&self, hir_id: HirId) -> Option<Node<'hir>> {
+        self.find(hir_id)
+    }
+
     fn body(&self, id: BodyId) -> &'hir Body<'hir> {
         self.body(id)
     }
@@ -982,23 +979,8 @@ pub(super) fn index_hir<'tcx>(tcx: TyCtxt<'tcx>, cnum: CrateNum) -> &'tcx Indexe
     tcx.arena.alloc(IndexedHir { crate_hash, map })
 }
 
-/// Identical to the `PpAnn` implementation for `hir::Crate`,
-/// except it avoids creating a dependency on the whole crate.
-impl<'hir> print::PpAnn for Map<'hir> {
-    fn nested(&self, state: &mut print::State<'_>, nested: print::Nested) {
-        match nested {
-            Nested::Item(id) => state.print_item(self.expect_item(id.id)),
-            Nested::TraitItem(id) => state.print_trait_item(self.trait_item(id)),
-            Nested::ImplItem(id) => state.print_impl_item(self.impl_item(id)),
-            Nested::Body(id) => state.print_expr(&self.body(id).value),
-            Nested::BodyParamPat(id, i) => state.print_pat(&self.body(id).params[i].pat),
-        }
-    }
-}
-
-fn hir_id_to_string(map: &Map<'_>, id: HirId, include_id: bool) -> String {
+fn hir_id_to_string(map: &Map<'_>, id: HirId) -> String {
     let id_str = format!(" (hir_id={})", id);
-    let id_str = if include_id { &id_str[..] } else { "" };
 
     let path_str = || {
         // This functionality is used for debugging, try to use `TyCtxt` to get
@@ -1019,6 +1001,9 @@ fn hir_id_to_string(map: &Map<'_>, id: HirId, include_id: bool) -> String {
         })
     };
 
+    let span_str = || map.tcx.sess.source_map().span_to_snippet(map.span(id)).unwrap_or_default();
+    let node_str = |prefix| format!("{} {}{}", prefix, span_str(), id_str);
+
     match map.find(id) {
         Some(Node::Item(item)) => {
             let item_str = match item.kind {
@@ -1069,22 +1054,20 @@ fn hir_id_to_string(map: &Map<'_>, id: HirId, include_id: bool) -> String {
         Some(Node::Field(ref field)) => {
             format!("field {} in {}{}", field.ident, path_str(), id_str)
         }
-        Some(Node::AnonConst(_)) => format!("const {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::Expr(_)) => format!("expr {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::Stmt(_)) => format!("stmt {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::PathSegment(_)) => {
-            format!("path segment {}{}", map.hir_to_pretty_string(id), id_str)
-        }
-        Some(Node::Ty(_)) => format!("type {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::TraitRef(_)) => format!("trait_ref {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::Binding(_)) => format!("local {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::Pat(_)) => format!("pat {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::Param(_)) => format!("param {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::Arm(_)) => format!("arm {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::Block(_)) => format!("block {}{}", map.hir_to_pretty_string(id), id_str),
-        Some(Node::Local(_)) => format!("local {}{}", map.hir_to_pretty_string(id), id_str),
+        Some(Node::AnonConst(_)) => node_str("const"),
+        Some(Node::Expr(_)) => node_str("expr"),
+        Some(Node::Stmt(_)) => node_str("stmt"),
+        Some(Node::PathSegment(_)) => node_str("path segment"),
+        Some(Node::Ty(_)) => node_str("type"),
+        Some(Node::TraitRef(_)) => node_str("trait ref"),
+        Some(Node::Binding(_)) => node_str("local"),
+        Some(Node::Pat(_)) => node_str("pat"),
+        Some(Node::Param(_)) => node_str("param"),
+        Some(Node::Arm(_)) => node_str("arm"),
+        Some(Node::Block(_)) => node_str("block"),
+        Some(Node::Local(_)) => node_str("local"),
         Some(Node::Ctor(..)) => format!("ctor {}{}", path_str(), id_str),
-        Some(Node::Lifetime(_)) => format!("lifetime {}{}", map.hir_to_pretty_string(id), id_str),
+        Some(Node::Lifetime(_)) => node_str("lifetime"),
         Some(Node::GenericParam(ref param)) => format!("generic_param {:?}{}", param, id_str),
         Some(Node::Visibility(ref vis)) => format!("visibility {:?}{}", vis, id_str),
         Some(Node::MacroDef(_)) => format!("macro {}{}", path_str(), id_str),
diff --git a/src/librustc_driver/Cargo.toml b/src/librustc_driver/Cargo.toml
index aec10ee5ef5..3ca39b24c52 100644
--- a/src/librustc_driver/Cargo.toml
+++ b/src/librustc_driver/Cargo.toml
@@ -21,6 +21,7 @@ rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_errors = { path = "../librustc_errors" }
 rustc_feature = { path = "../librustc_feature" }
 rustc_hir = { path = "../librustc_hir" }
+rustc_hir_pretty = { path = "../librustc_hir_pretty" }
 rustc_metadata = { path = "../librustc_metadata" }
 rustc_mir = { path = "../librustc_mir" }
 rustc_parse = { path = "../librustc_parse" }
diff --git a/src/librustc_driver/pretty.rs b/src/librustc_driver/pretty.rs
index 1e5cc55a828..a57a70e6b8c 100644
--- a/src/librustc_driver/pretty.rs
+++ b/src/librustc_driver/pretty.rs
@@ -7,7 +7,7 @@ use rustc_ast::ast;
 use rustc_ast_pretty::pprust;
 use rustc_hir as hir;
 use rustc_hir::def_id::LOCAL_CRATE;
-use rustc_hir::print as pprust_hir;
+use rustc_hir_pretty as pprust_hir;
 use rustc_mir::util::{write_mir_graphviz, write_mir_pretty};
 use rustc_session::config::{Input, PpMode, PpSourceMode};
 use rustc_session::Session;
@@ -155,7 +155,7 @@ impl<'hir> pprust::PpAnn for NoAnn<'hir> {}
 impl<'hir> pprust_hir::PpAnn for NoAnn<'hir> {
     fn nested(&self, state: &mut pprust_hir::State<'_>, nested: pprust_hir::Nested) {
         if let Some(tcx) = self.tcx {
-            pprust_hir::PpAnn::nested(&tcx.hir(), state, nested)
+            pprust_hir::PpAnn::nested(&(&tcx.hir() as &dyn hir::intravisit::Map<'_>), state, nested)
         }
     }
 }
@@ -228,7 +228,7 @@ impl<'hir> HirPrinterSupport<'hir> for IdentifiedAnnotation<'hir> {
 impl<'hir> pprust_hir::PpAnn for IdentifiedAnnotation<'hir> {
     fn nested(&self, state: &mut pprust_hir::State<'_>, nested: pprust_hir::Nested) {
         if let Some(ref tcx) = self.tcx {
-            pprust_hir::PpAnn::nested(&tcx.hir(), state, nested)
+            pprust_hir::PpAnn::nested(&(&tcx.hir() as &dyn hir::intravisit::Map<'_>), state, nested)
         }
     }
     fn pre(&self, s: &mut pprust_hir::State<'_>, node: pprust_hir::AnnNode<'_>) {
@@ -334,7 +334,8 @@ impl<'a, 'tcx> pprust_hir::PpAnn for TypedAnnotation<'a, 'tcx> {
         if let pprust_hir::Nested::Body(id) = nested {
             self.tables.set(self.tcx.body_tables(id));
         }
-        pprust_hir::PpAnn::nested(&self.tcx.hir(), state, nested);
+        let pp_ann = &(&self.tcx.hir() as &dyn hir::intravisit::Map<'_>);
+        pprust_hir::PpAnn::nested(pp_ann, state, nested);
         self.tables.set(old_tables);
     }
     fn pre(&self, s: &mut pprust_hir::State<'_>, node: pprust_hir::AnnNode<'_>) {
diff --git a/src/librustc_hir/Cargo.toml b/src/librustc_hir/Cargo.toml
index b3682ea5a80..811440fdeb9 100644
--- a/src/librustc_hir/Cargo.toml
+++ b/src/librustc_hir/Cargo.toml
@@ -10,13 +10,11 @@ path = "lib.rs"
 doctest = false
 
 [dependencies]
-rustc_ast_pretty = { path = "../librustc_ast_pretty" }
 rustc_target = { path = "../librustc_target" }
 rustc_macros = { path = "../librustc_macros" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_index = { path = "../librustc_index" }
 rustc_span = { path = "../librustc_span" }
-rustc_errors = { path = "../librustc_errors" }
 rustc_serialize = { path = "../libserialize", package = "serialize" }
 rustc_ast = { path = "../librustc_ast" }
 lazy_static = "1"
diff --git a/src/librustc_hir/hir.rs b/src/librustc_hir/hir.rs
index bb864edc999..2054759933f 100644
--- a/src/librustc_hir/hir.rs
+++ b/src/librustc_hir/hir.rs
@@ -2,11 +2,6 @@ use crate::def::{DefKind, Namespace, Res};
 use crate::def_id::DefId;
 crate use crate::hir_id::HirId;
 use crate::itemlikevisit;
-use crate::print;
-
-crate use BlockCheckMode::*;
-crate use FnRetTy::*;
-crate use UnsafeSource::*;
 
 use rustc_ast::ast::{self, AsmDialect, CrateSugar, Ident, Name};
 use rustc_ast::ast::{AttrVec, Attribute, FloatTy, IntTy, Label, LitKind, StrStyle, UintTy};
@@ -16,7 +11,6 @@ use rustc_ast::node_id::NodeMap;
 use rustc_ast::util::parser::ExprPrecedence;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::sync::{par_for_each_in, Send, Sync};
-use rustc_errors::FatalError;
 use rustc_macros::HashStable_Generic;
 use rustc_span::source_map::{SourceMap, Spanned};
 use rustc_span::symbol::{kw, sym, Symbol};
@@ -169,12 +163,7 @@ impl fmt::Display for Lifetime {
 
 impl fmt::Debug for Lifetime {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(
-            f,
-            "lifetime({}: {})",
-            self.hir_id,
-            print::to_string(print::NO_ANN, |s| s.print_lifetime(self))
-        )
+        write!(f, "lifetime({}: {})", self.hir_id, self.name.ident())
     }
 }
 
@@ -191,7 +180,7 @@ impl Lifetime {
 /// A `Path` is essentially Rust's notion of a name; for instance,
 /// `std::cmp::PartialEq`. It's represented as a sequence of identifiers,
 /// along with a bunch of supporting information.
-#[derive(RustcEncodable, RustcDecodable, HashStable_Generic)]
+#[derive(RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
 pub struct Path<'hir> {
     pub span: Span,
     /// The resolution for the path.
@@ -206,18 +195,6 @@ impl Path<'_> {
     }
 }
 
-impl fmt::Debug for Path<'_> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "path({})", self)
-    }
-}
-
-impl fmt::Display for Path<'_> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "{}", print::to_string(print::NO_ANN, |s| s.print_path(self, false)))
-    }
-}
-
 /// A segment of a path: an identifier, an optional lifetime, and a set of
 /// types.
 #[derive(RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
@@ -388,9 +365,9 @@ pub enum GenericBound<'hir> {
 }
 
 impl GenericBound<'_> {
-    pub fn trait_def_id(&self) -> Option<DefId> {
+    pub fn trait_ref(&self) -> Option<&TraitRef<'_>> {
         match self {
-            GenericBound::Trait(data, _) => Some(data.trait_ref.trait_def_id()),
+            GenericBound::Trait(data, _) => Some(&data.trait_ref),
             _ => None,
         }
     }
@@ -758,7 +735,7 @@ pub struct Block<'hir> {
     pub targeted_by_break: bool,
 }
 
-#[derive(RustcEncodable, RustcDecodable, HashStable_Generic)]
+#[derive(Debug, RustcEncodable, RustcDecodable, HashStable_Generic)]
 pub struct Pat<'hir> {
     #[stable_hasher(ignore)]
     pub hir_id: HirId,
@@ -766,17 +743,6 @@ pub struct Pat<'hir> {
     pub span: Span,
 }
 
-impl fmt::Debug for Pat<'_> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(
-            f,
-            "pat({}: {})",
-            self.hir_id,
-            print::to_string(print::NO_ANN, |s| s.print_pat(self))
-        )
-    }
-}
-
 impl Pat<'_> {
     // FIXME(#19596) this is a workaround, but there should be a better way
     fn walk_short_(&self, it: &mut impl FnMut(&Pat<'_>) -> bool) -> bool {
@@ -1118,26 +1084,15 @@ impl UnOp {
 }
 
 /// A statement.
-#[derive(RustcEncodable, RustcDecodable, HashStable_Generic)]
+#[derive(RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
 pub struct Stmt<'hir> {
     pub hir_id: HirId,
     pub kind: StmtKind<'hir>,
     pub span: Span,
 }
 
-impl fmt::Debug for Stmt<'_> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(
-            f,
-            "stmt({}: {})",
-            self.hir_id,
-            print::to_string(print::NO_ANN, |s| s.print_stmt(self))
-        )
-    }
-}
-
 /// The contents of a statement.
-#[derive(RustcEncodable, RustcDecodable, HashStable_Generic)]
+#[derive(RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
 pub enum StmtKind<'hir> {
     /// A local (`let`) binding.
     Local(&'hir Local<'hir>),
@@ -1351,7 +1306,7 @@ pub struct AnonConst {
 }
 
 /// An expression.
-#[derive(RustcEncodable, RustcDecodable)]
+#[derive(Debug, RustcEncodable, RustcDecodable)]
 pub struct Expr<'hir> {
     pub hir_id: HirId,
     pub kind: ExprKind<'hir>,
@@ -1472,17 +1427,6 @@ impl Expr<'_> {
     }
 }
 
-impl fmt::Debug for Expr<'_> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(
-            f,
-            "expr({}: {})",
-            self.hir_id,
-            print::to_string(print::NO_ANN, |s| s.print_expr(self))
-        )
-    }
-}
-
 /// Checks if the specified expression is a built-in range literal.
 /// (See: `LoweringContext::lower_expr()`).
 ///
@@ -1965,19 +1909,13 @@ impl TypeBinding<'_> {
     }
 }
 
-#[derive(RustcEncodable, RustcDecodable)]
+#[derive(Debug, RustcEncodable, RustcDecodable)]
 pub struct Ty<'hir> {
     pub hir_id: HirId,
     pub kind: TyKind<'hir>,
     pub span: Span,
 }
 
-impl fmt::Debug for Ty<'_> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "type({})", print::to_string(print::NO_ANN, |s| s.print_type(self)))
-    }
-}
-
 /// Not represented directly in the AST; referred to by name through a `ty_path`.
 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 #[derive(HashStable_Generic)]
@@ -2182,15 +2120,6 @@ pub enum FnRetTy<'hir> {
     Return(&'hir Ty<'hir>),
 }
 
-impl fmt::Display for FnRetTy<'_> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            Self::Return(ref ty) => print::to_string(print::NO_ANN, |s| s.print_type(ty)).fmt(f),
-            Self::DefaultReturn(_) => "()".fmt(f),
-        }
-    }
-}
-
 impl FnRetTy<'_> {
     pub fn span(&self) -> Span {
         match *self {
@@ -2274,13 +2203,10 @@ pub struct TraitRef<'hir> {
 
 impl TraitRef<'_> {
     /// Gets the `DefId` of the referenced trait. It _must_ actually be a trait or trait alias.
-    pub fn trait_def_id(&self) -> DefId {
+    pub fn trait_def_id(&self) -> Option<DefId> {
         match self.path.res {
-            Res::Def(DefKind::Trait, did) => did,
-            Res::Def(DefKind::TraitAlias, did) => did,
-            Res::Err => {
-                FatalError.raise();
-            }
+            Res::Def(DefKind::Trait | DefKind::TraitAlias, did) => Some(did),
+            Res::Err => None,
             _ => unreachable!(),
         }
     }
diff --git a/src/librustc_hir/intravisit.rs b/src/librustc_hir/intravisit.rs
index 11749cf996b..08b4ef1b918 100644
--- a/src/librustc_hir/intravisit.rs
+++ b/src/librustc_hir/intravisit.rs
@@ -121,6 +121,8 @@ impl<'a> FnKind<'a> {
 
 /// An abstract representation of the HIR `rustc::hir::map::Map`.
 pub trait Map<'hir> {
+    /// Retrieves the `Node` corresponding to `id`, returning `None` if cannot be found.
+    fn find(&self, hir_id: HirId) -> Option<Node<'hir>>;
     fn body(&self, id: BodyId) -> &'hir Body<'hir>;
     fn item(&self, id: HirId) -> &'hir Item<'hir>;
     fn trait_item(&self, id: TraitItemId) -> &'hir TraitItem<'hir>;
@@ -132,6 +134,9 @@ pub trait Map<'hir> {
 pub struct ErasedMap<'hir>(&'hir dyn Map<'hir>);
 
 impl<'hir> Map<'hir> for ErasedMap<'hir> {
+    fn find(&self, _: HirId) -> Option<Node<'hir>> {
+        None
+    }
     fn body(&self, id: BodyId) -> &'hir Body<'hir> {
         self.0.body(id)
     }
diff --git a/src/librustc_hir/lib.rs b/src/librustc_hir/lib.rs
index fbb3d6b2af3..49692c73fad 100644
--- a/src/librustc_hir/lib.rs
+++ b/src/librustc_hir/lib.rs
@@ -7,6 +7,7 @@
 #![feature(const_fn)] // For the unsizing cast on `&[]`
 #![feature(const_panic)]
 #![feature(in_band_lifetimes)]
+#![feature(or_patterns)]
 #![feature(specialization)]
 #![recursion_limit = "256"]
 
@@ -23,7 +24,6 @@ pub mod intravisit;
 pub mod itemlikevisit;
 pub mod lang_items;
 pub mod pat_util;
-pub mod print;
 mod stable_hash_impls;
 mod target;
 pub mod weak_lang_items;
diff --git a/src/librustc_hir_pretty/Cargo.toml b/src/librustc_hir_pretty/Cargo.toml
new file mode 100644
index 00000000000..6a9339b4b9c
--- /dev/null
+++ b/src/librustc_hir_pretty/Cargo.toml
@@ -0,0 +1,18 @@
+[package]
+authors = ["The Rust Project Developers"]
+name = "rustc_hir_pretty"
+version = "0.0.0"
+edition = "2018"
+
+[lib]
+name = "rustc_hir_pretty"
+path = "lib.rs"
+doctest = false
+
+[dependencies]
+rustc_ast_pretty = { path = "../librustc_ast_pretty" }
+rustc_hir = { path = "../librustc_hir" }
+rustc_target = { path = "../librustc_target" }
+rustc_data_structures = { path = "../librustc_data_structures" }
+rustc_span = { path = "../librustc_span" }
+rustc_ast = { path = "../librustc_ast" }
diff --git a/src/librustc_hir/print.rs b/src/librustc_hir_pretty/lib.rs
index cd16e451f1d..88b1288848f 100644
--- a/src/librustc_hir/print.rs
+++ b/src/librustc_hir_pretty/lib.rs
@@ -1,21 +1,26 @@
+#![recursion_limit = "256"]
+
 use rustc_ast::ast;
 use rustc_ast::util::parser::{self, AssocOp, Fixity};
 use rustc_ast_pretty::pp::Breaks::{Consistent, Inconsistent};
 use rustc_ast_pretty::pp::{self, Breaks};
 use rustc_ast_pretty::pprust::{Comments, PrintState};
+use rustc_hir as hir;
+use rustc_hir::{GenericArg, GenericParam, GenericParamKind, Node};
+use rustc_hir::{GenericBound, PatKind, RangeEnd, TraitBoundModifier};
 use rustc_span::source_map::{SourceMap, Spanned};
 use rustc_span::symbol::{kw, IdentPrinter};
 use rustc_span::{self, BytePos, FileName};
 use rustc_target::spec::abi::Abi;
 
-use crate::hir;
-use crate::hir::{GenericArg, GenericParam, GenericParamKind, Node};
-use crate::hir::{GenericBound, PatKind, RangeEnd, TraitBoundModifier};
-
 use std::borrow::Cow;
 use std::cell::Cell;
 use std::vec;
 
+pub fn id_to_string(map: &dyn rustc_hir::intravisit::Map<'_>, hir_id: hir::HirId) -> String {
+    to_string(&map, |s| s.print_node(map.find(hir_id).unwrap()))
+}
+
 pub enum AnnNode<'a> {
     Name(&'a ast::Name),
     Block(&'a hir::Block<'a>),
@@ -47,7 +52,7 @@ pub struct NoAnn;
 impl PpAnn for NoAnn {}
 pub const NO_ANN: &dyn PpAnn = &NoAnn;
 
-impl PpAnn for hir::Crate<'a> {
+impl PpAnn for hir::Crate<'_> {
     fn try_fetch_item(&self, item: hir::HirId) -> Option<&hir::Item<'_>> {
         Some(self.item(item))
     }
@@ -62,6 +67,20 @@ impl PpAnn for hir::Crate<'a> {
     }
 }
 
+/// Identical to the `PpAnn` implementation for `hir::Crate`,
+/// except it avoids creating a dependency on the whole crate.
+impl PpAnn for &dyn rustc_hir::intravisit::Map<'_> {
+    fn nested(&self, state: &mut State<'_>, nested: Nested) {
+        match nested {
+            Nested::Item(id) => state.print_item(self.item(id.id)),
+            Nested::TraitItem(id) => state.print_trait_item(self.trait_item(id)),
+            Nested::ImplItem(id) => state.print_impl_item(self.impl_item(id)),
+            Nested::Body(id) => state.print_expr(&self.body(id).value),
+            Nested::BodyParamPat(id, i) => state.print_pat(&self.body(id).params[i].pat),
+        }
+    }
+}
+
 pub struct State<'a> {
     pub s: pp::Printer,
     comments: Option<Comments<'a>>,
@@ -1006,10 +1025,10 @@ impl<'a> State<'a> {
         close_box: bool,
     ) {
         match blk.rules {
-            hir::UnsafeBlock(..) => self.word_space("unsafe"),
-            hir::PushUnsafeBlock(..) => self.word_space("push_unsafe"),
-            hir::PopUnsafeBlock(..) => self.word_space("pop_unsafe"),
-            hir::DefaultBlock => (),
+            hir::BlockCheckMode::UnsafeBlock(..) => self.word_space("unsafe"),
+            hir::BlockCheckMode::PushUnsafeBlock(..) => self.word_space("push_unsafe"),
+            hir::BlockCheckMode::PopUnsafeBlock(..) => self.word_space("pop_unsafe"),
+            hir::BlockCheckMode::DefaultBlock => (),
         }
         self.maybe_print_comment(blk.span.lo());
         self.ann.pre(self, AnnNode::Block(blk));
@@ -1092,7 +1111,7 @@ impl<'a> State<'a> {
         &mut self,
         qpath: &hir::QPath<'_>,
         fields: &[hir::Field<'_>],
-        wth: &Option<&'hir hir::Expr<'_>>,
+        wth: &Option<&hir::Expr<'_>>,
     ) {
         self.print_qpath(qpath, true);
         self.s.word("{");
@@ -1848,7 +1867,8 @@ impl<'a> State<'a> {
                 self.print_block_unclosed(&blk);
 
                 // If it is a user-provided unsafe block, print a comma after it
-                if let hir::UnsafeBlock(hir::UserProvided) = blk.rules {
+                if let hir::BlockCheckMode::UnsafeBlock(hir::UnsafeSource::UserProvided) = blk.rules
+                {
                     self.s.word(",");
                 }
             }
@@ -1928,18 +1948,18 @@ impl<'a> State<'a> {
         });
         self.s.word("|");
 
-        if let hir::DefaultReturn(..) = decl.output {
+        if let hir::FnRetTy::DefaultReturn(..) = decl.output {
             return;
         }
 
         self.space_if_not_bol();
         self.word_space("->");
         match decl.output {
-            hir::Return(ref ty) => {
+            hir::FnRetTy::Return(ref ty) => {
                 self.print_type(&ty);
                 self.maybe_print_comment(ty.span.lo())
             }
-            hir::DefaultReturn(..) => unreachable!(),
+            hir::FnRetTy::DefaultReturn(..) => unreachable!(),
         }
     }
 
@@ -2112,7 +2132,7 @@ impl<'a> State<'a> {
     }
 
     pub fn print_fn_output(&mut self, decl: &hir::FnDecl<'_>) {
-        if let hir::DefaultReturn(..) = decl.output {
+        if let hir::FnRetTy::DefaultReturn(..) = decl.output {
             return;
         }
 
@@ -2120,13 +2140,13 @@ impl<'a> State<'a> {
         self.ibox(INDENT_UNIT);
         self.word_space("->");
         match decl.output {
-            hir::DefaultReturn(..) => unreachable!(),
-            hir::Return(ref ty) => self.print_type(&ty),
+            hir::FnRetTy::DefaultReturn(..) => unreachable!(),
+            hir::FnRetTy::Return(ref ty) => self.print_type(&ty),
         }
         self.end();
 
         match decl.output {
-            hir::Return(ref output) => self.maybe_print_comment(output.span.lo()),
+            hir::FnRetTy::Return(ref output) => self.maybe_print_comment(output.span.lo()),
             _ => {}
         }
     }
diff --git a/src/librustc_metadata/Cargo.toml b/src/librustc_metadata/Cargo.toml
index 088cba83ef9..ea439b1f41d 100644
--- a/src/librustc_metadata/Cargo.toml
+++ b/src/librustc_metadata/Cargo.toml
@@ -19,6 +19,7 @@ rustc_attr = { path = "../librustc_attr" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_errors = { path = "../librustc_errors" }
 rustc_hir = { path = "../librustc_hir" }
+rustc_hir_pretty = { path = "../librustc_hir_pretty" }
 rustc_target = { path = "../librustc_target" }
 rustc_index = { path = "../librustc_index" }
 rustc_serialize = { path = "../libserialize", package = "serialize" }
diff --git a/src/librustc_metadata/rmeta/encoder.rs b/src/librustc_metadata/rmeta/encoder.rs
index 9718d192816..3686b2f2048 100644
--- a/src/librustc_metadata/rmeta/encoder.rs
+++ b/src/librustc_metadata/rmeta/encoder.rs
@@ -824,8 +824,10 @@ impl EncodeContext<'tcx> {
 
         record!(self.per_def.kind[def_id] <- match trait_item.kind {
             ty::AssocKind::Const => {
-                let rendered =
-                    hir::print::to_string(&self.tcx.hir(), |s| s.print_trait_item(ast_item));
+                let rendered = rustc_hir_pretty::to_string(
+                    &(&self.tcx.hir() as &dyn intravisit::Map<'_>),
+                    |s| s.print_trait_item(ast_item)
+                );
                 let rendered_const = self.lazy(RenderedConst(rendered));
 
                 EntryKind::AssocConst(
@@ -1044,8 +1046,11 @@ impl EncodeContext<'tcx> {
     }
 
     fn encode_rendered_const_for_body(&mut self, body_id: hir::BodyId) -> Lazy<RenderedConst> {
-        let body = self.tcx.hir().body(body_id);
-        let rendered = hir::print::to_string(&self.tcx.hir(), |s| s.print_expr(&body.value));
+        let hir = self.tcx.hir();
+        let body = hir.body(body_id);
+        let rendered = rustc_hir_pretty::to_string(&(&hir as &dyn intravisit::Map<'_>), |s| {
+            s.print_expr(&body.value)
+        });
         let rendered_const = &RenderedConst(rendered);
         self.lazy(rendered_const)
     }
diff --git a/src/librustc_passes/liveness.rs b/src/librustc_passes/liveness.rs
index 97f6457d397..e729c2d517f 100644
--- a/src/librustc_passes/liveness.rs
+++ b/src/librustc_passes/liveness.rs
@@ -903,10 +903,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
     }
 
     fn compute(&mut self, body: &hir::Expr<'_>) -> LiveNode {
-        debug!(
-            "compute: using id for body, {}",
-            self.ir.tcx.hir().hir_to_pretty_string(body.hir_id)
-        );
+        debug!("compute: using id for body, {:?}", body);
 
         // the fallthrough exit is only for those cases where we do not
         // explicitly return:
@@ -979,7 +976,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
     }
 
     fn propagate_through_expr(&mut self, expr: &Expr<'_>, succ: LiveNode) -> LiveNode {
-        debug!("propagate_through_expr: {}", self.ir.tcx.hir().hir_to_pretty_string(expr.hir_id));
+        debug!("propagate_through_expr: {:?}", expr);
 
         match expr.kind {
             // Interesting cases with control flow or which gen/kill
@@ -990,10 +987,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
             hir::ExprKind::Field(ref e, _) => self.propagate_through_expr(&e, succ),
 
             hir::ExprKind::Closure(..) => {
-                debug!(
-                    "{} is an ExprKind::Closure",
-                    self.ir.tcx.hir().hir_to_pretty_string(expr.hir_id)
-                );
+                debug!("{:?} is an ExprKind::Closure", expr);
 
                 // the construction of a closure itself is not important,
                 // but we have to consider the closed over variables.
@@ -1344,11 +1338,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
         let mut first_merge = true;
         let ln = self.live_node(expr.hir_id, expr.span);
         self.init_empty(ln, succ);
-        debug!(
-            "propagate_through_loop: using id for loop body {} {}",
-            expr.hir_id,
-            self.ir.tcx.hir().hir_to_pretty_string(body.hir_id)
-        );
+        debug!("propagate_through_loop: using id for loop body {} {:?}", expr.hir_id, body);
 
         self.break_ln.insert(expr.hir_id, succ);
 
diff --git a/src/librustc_privacy/lib.rs b/src/librustc_privacy/lib.rs
index 8734cee366a..0df1d08cbd8 100644
--- a/src/librustc_privacy/lib.rs
+++ b/src/librustc_privacy/lib.rs
@@ -1320,14 +1320,18 @@ impl<'a, 'tcx> Visitor<'tcx> for TypePrivacyVisitor<'a, 'tcx> {
             let is_local_static =
                 if let DefKind::Static = kind { def_id.is_local() } else { false };
             if !self.item_is_accessible(def_id) && !is_local_static {
-                let name = match *qpath {
-                    hir::QPath::Resolved(_, ref path) => path.to_string(),
-                    hir::QPath::TypeRelative(_, ref segment) => segment.ident.to_string(),
+                let sess = self.tcx.sess;
+                let sm = sess.source_map();
+                let name = match qpath {
+                    hir::QPath::Resolved(_, path) => sm.span_to_snippet(path.span).ok(),
+                    hir::QPath::TypeRelative(_, segment) => Some(segment.ident.to_string()),
                 };
                 let kind = kind.descr(def_id);
-                self.tcx
-                    .sess
-                    .struct_span_err(span, &format!("{} `{}` is private", kind, name))
+                let msg = match name {
+                    Some(name) => format!("{} `{}` is private", kind, name),
+                    None => format!("{} is private", kind),
+                };
+                sess.struct_span_err(span, &msg)
                     .span_label(span, &format!("private {}", kind))
                     .emit();
                 return;
diff --git a/src/librustc_save_analysis/Cargo.toml b/src/librustc_save_analysis/Cargo.toml
index de851d97727..623da1ddcb4 100644
--- a/src/librustc_save_analysis/Cargo.toml
+++ b/src/librustc_save_analysis/Cargo.toml
@@ -11,13 +11,14 @@ path = "lib.rs"
 [dependencies]
 log = "0.4"
 rustc = { path = "../librustc" }
+rustc_ast = { path = "../librustc_ast" }
 rustc_ast_pretty = { path = "../librustc_ast_pretty" }
 rustc_data_structures = { path = "../librustc_data_structures" }
-rustc_session = { path = "../librustc_session" }
 rustc_hir = { path = "../librustc_hir" }
+rustc_hir_pretty = { path = "../librustc_hir_pretty" }
 rustc_parse = { path = "../librustc_parse" }
 serde_json = "1"
-rustc_ast = { path = "../librustc_ast" }
+rustc_session = { path = "../librustc_session" }
 rustc_span = { path = "../librustc_span" }
 rls-data = "0.19"
 rls-span = "0.5"
diff --git a/src/librustc_save_analysis/lib.rs b/src/librustc_save_analysis/lib.rs
index 024633c3b3d..21551eeddb9 100644
--- a/src/librustc_save_analysis/lib.rs
+++ b/src/librustc_save_analysis/lib.rs
@@ -404,14 +404,15 @@ impl<'l, 'tcx> SaveContext<'l, 'tcx> {
             Some(impl_id) => match self.tcx.hir().get_if_local(impl_id) {
                 Some(Node::Item(item)) => match item.kind {
                     hir::ItemKind::Impl { ref self_ty, .. } => {
+                        let hir = self.tcx.hir();
+
                         let mut qualname = String::from("<");
-                        qualname.push_str(&self.tcx.hir().hir_to_pretty_string(self_ty.hir_id));
+                        qualname.push_str(&rustc_hir_pretty::id_to_string(&hir, self_ty.hir_id));
 
                         let trait_id = self.tcx.trait_id_of_impl(impl_id);
                         let mut docs = String::new();
                         let mut attrs = vec![];
-                        let hir_id = self.tcx.hir().node_to_hir_id(id);
-                        if let Some(Node::ImplItem(item)) = self.tcx.hir().find(hir_id) {
+                        if let Some(Node::ImplItem(item)) = hir.find(hir.node_to_hir_id(id)) {
                             docs = self.docs_for_attrs(&item.attrs);
                             attrs = item.attrs.to_vec();
                         }
diff --git a/src/librustc_trait_selection/traits/error_reporting/mod.rs b/src/librustc_trait_selection/traits/error_reporting/mod.rs
index 12939519fc2..8cbed43cac0 100644
--- a/src/librustc_trait_selection/traits/error_reporting/mod.rs
+++ b/src/librustc_trait_selection/traits/error_reporting/mod.rs
@@ -1581,7 +1581,8 @@ impl<'a, 'tcx> InferCtxtPrivExt<'tcx> for InferCtxt<'a, 'tcx> {
                 for param in generics.params {
                     if param.span == *span
                         && !param.bounds.iter().any(|bound| {
-                            bound.trait_def_id() == self.tcx.lang_items().sized_trait()
+                            bound.trait_ref().and_then(|trait_ref| trait_ref.trait_def_id())
+                                == self.tcx.lang_items().sized_trait()
                         })
                     {
                         let (span, separator) = match param.bounds {
diff --git a/src/librustc_trait_selection/traits/object_safety.rs b/src/librustc_trait_selection/traits/object_safety.rs
index 5cc1da045fc..7d4ad61902a 100644
--- a/src/librustc_trait_selection/traits/object_safety.rs
+++ b/src/librustc_trait_selection/traits/object_safety.rs
@@ -15,7 +15,7 @@ use crate::traits::query::evaluate_obligation::InferCtxtExt;
 use crate::traits::{self, Obligation, ObligationCause};
 use rustc::ty::subst::{InternalSubsts, Subst};
 use rustc::ty::{self, Predicate, ToPredicate, Ty, TyCtxt, TypeFoldable, WithConstness};
-use rustc_errors::Applicability;
+use rustc_errors::{Applicability, FatalError};
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_session::lint::builtin::WHERE_CLAUSES_OBJECT_SAFETY;
@@ -170,6 +170,24 @@ fn object_safety_violations_for_trait(
     violations
 }
 
+fn sized_trait_bound_spans<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    bounds: hir::GenericBounds<'tcx>,
+) -> impl 'tcx + Iterator<Item = Span> {
+    bounds.iter().filter_map(move |b| match b {
+        hir::GenericBound::Trait(trait_ref, hir::TraitBoundModifier::None)
+            if trait_has_sized_self(
+                tcx,
+                trait_ref.trait_ref.trait_def_id().unwrap_or_else(|| FatalError.raise()),
+            ) =>
+        {
+            // Fetch spans for supertraits that are `Sized`: `trait T: Super`
+            Some(trait_ref.span)
+        }
+        _ => None,
+    })
+}
+
 fn get_sized_bounds(tcx: TyCtxt<'_>, trait_def_id: DefId) -> SmallVec<[Span; 1]> {
     tcx.hir()
         .get_if_local(trait_def_id)
@@ -189,33 +207,14 @@ fn get_sized_bounds(tcx: TyCtxt<'_>, trait_def_id: DefId) -> SmallVec<[Span; 1]>
                             {
                                 // Fetch spans for trait bounds that are Sized:
                                 // `trait T where Self: Pred`
-                                Some(pred.bounds.iter().filter_map(|b| match b {
-                                    hir::GenericBound::Trait(
-                                        trait_ref,
-                                        hir::TraitBoundModifier::None,
-                                    ) if trait_has_sized_self(
-                                        tcx,
-                                        trait_ref.trait_ref.trait_def_id(),
-                                    ) =>
-                                    {
-                                        Some(trait_ref.span)
-                                    }
-                                    _ => None,
-                                }))
+                                Some(sized_trait_bound_spans(tcx, pred.bounds))
                             }
                             _ => None,
                         }
                     })
                     .flatten()
-                    .chain(bounds.iter().filter_map(|b| match b {
-                        hir::GenericBound::Trait(trait_ref, hir::TraitBoundModifier::None)
-                            if trait_has_sized_self(tcx, trait_ref.trait_ref.trait_def_id()) =>
-                        {
-                            // Fetch spans for supertraits that are `Sized`: `trait T: Super`
-                            Some(trait_ref.span)
-                        }
-                        _ => None,
-                    }))
+                    // Fetch spans for supertraits that are `Sized`: `trait T: Super`.
+                    .chain(sized_trait_bound_spans(tcx, bounds))
                     .collect::<SmallVec<[Span; 1]>>(),
             ),
             _ => None,
diff --git a/src/librustc_typeck/astconv.rs b/src/librustc_typeck/astconv.rs
index 54c646b8557..07630d7969e 100644
--- a/src/librustc_typeck/astconv.rs
+++ b/src/librustc_typeck/astconv.rs
@@ -16,12 +16,11 @@ use rustc::ty::{GenericParamDef, GenericParamDefKind};
 use rustc_ast::ast;
 use rustc_ast::util::lev_distance::find_best_match_for_name;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
-use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticId};
+use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticId, FatalError};
 use rustc_hir as hir;
 use rustc_hir::def::{CtorOf, DefKind, Namespace, Res};
 use rustc_hir::def_id::DefId;
-use rustc_hir::intravisit::{walk_generics, Visitor};
-use rustc_hir::print;
+use rustc_hir::intravisit::{walk_generics, Visitor as _};
 use rustc_hir::{Constness, GenericArg, GenericArgs};
 use rustc_session::lint::builtin::{AMBIGUOUS_ASSOCIATED_ITEMS, LATE_BOUND_LIFETIME_ARGUMENTS};
 use rustc_session::parse::feature_err;
@@ -991,7 +990,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
 
         self.ast_path_to_mono_trait_ref(
             trait_ref.path.span,
-            trait_ref.trait_def_id(),
+            trait_ref.trait_def_id().unwrap_or_else(|| FatalError.raise()),
             self_ty,
             trait_ref.path.segments.last().unwrap(),
         )
@@ -1007,7 +1006,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         bounds: &mut Bounds<'tcx>,
         speculative: bool,
     ) -> Result<(), GenericArgCountMismatch> {
-        let trait_def_id = trait_ref.trait_def_id();
+        let trait_def_id = trait_ref.trait_def_id().unwrap_or_else(|| FatalError.raise());
 
         debug!("instantiate_poly_trait_ref({:?}, def_id={:?})", trait_ref, trait_def_id);
 
@@ -1118,6 +1117,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         if !self.tcx().features().unboxed_closures
             && trait_segment.generic_args().parenthesized != trait_def.paren_sugar
         {
+            let sess = &self.tcx().sess.parse_sess;
             // For now, require that parenthetical notation be used only with `Fn()` etc.
             let (msg, sugg) = if trait_def.paren_sugar {
                 (
@@ -1132,7 +1132,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                             .and_then(|args| args.args.get(0))
                             .and_then(|arg| match arg {
                                 hir::GenericArg::Type(ty) => {
-                                    Some(print::to_string(print::NO_ANN, |s| s.print_type(ty)))
+                                    sess.source_map().span_to_snippet(ty.span).ok()
                                 }
                                 _ => None,
                             })
@@ -1143,7 +1143,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                             .iter()
                             .filter_map(|b| match (b.ident.as_str() == "Output", &b.kind) {
                                 (true, hir::TypeBindingKind::Equality { ty }) => {
-                                    Some(print::to_string(print::NO_ANN, |s| s.print_type(ty)))
+                                    sess.source_map().span_to_snippet(ty.span).ok()
                                 }
                                 _ => None,
                             })
@@ -1154,7 +1154,6 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             } else {
                 ("parenthetical notation is only stable when used with `Fn`-family traits", None)
             };
-            let sess = &self.tcx().sess.parse_sess;
             let mut err = feature_err(sess, sym::unboxed_closures, span, msg);
             if let Some(sugg) = sugg {
                 let msg = "use parenthetical notation instead";
diff --git a/src/librustc_typeck/check/_match.rs b/src/librustc_typeck/check/_match.rs
index a34389b7d89..b44bab2675d 100644
--- a/src/librustc_typeck/check/_match.rs
+++ b/src/librustc_typeck/check/_match.rs
@@ -245,11 +245,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             {
                 // check that the `if` expr without `else` is the fn body's expr
                 if expr.span == span {
-                    return self.get_fn_decl(hir_id).map(|(fn_decl, _)| {
-                        (
-                            fn_decl.output.span(),
-                            format!("expected `{}` because of this return type", fn_decl.output),
-                        )
+                    return self.get_fn_decl(hir_id).and_then(|(fn_decl, _)| {
+                        let span = fn_decl.output.span();
+                        let snippet = self.tcx.sess.source_map().span_to_snippet(span).ok()?;
+                        Some((span, format!("expected `{}` because of this return type", snippet)))
                     });
                 }
             }
diff --git a/src/librustc_typeck/check/callee.rs b/src/librustc_typeck/check/callee.rs
index ec796043d3a..074951684ef 100644
--- a/src/librustc_typeck/check/callee.rs
+++ b/src/librustc_typeck/check/callee.rs
@@ -265,7 +265,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 if let &ty::Adt(adt_def, ..) = t {
                     if adt_def.is_enum() {
                         if let hir::ExprKind::Call(ref expr, _) = call_expr.kind {
-                            unit_variant = Some(self.tcx.hir().hir_to_pretty_string(expr.hir_id))
+                            unit_variant =
+                                self.tcx.sess.source_map().span_to_snippet(expr.span).ok();
                         }
                     }
                 }
@@ -335,16 +336,19 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     err.span_label(call_expr.span, "call expression requires function");
 
                     if let Some(span) = self.tcx.hir().res_span(def) {
+                        let callee_ty = callee_ty.to_string();
                         let label = match (unit_variant, inner_callee_path) {
-                            (Some(path), _) => format!("`{}` defined here", path),
-                            (_, Some(hir::QPath::Resolved(_, path))) => format!(
-                                "`{}` defined here returns `{}`",
-                                path,
-                                callee_ty.to_string()
-                            ),
-                            _ => format!("`{}` defined here", callee_ty.to_string()),
+                            (Some(path), _) => Some(format!("`{}` defined here", path)),
+                            (_, Some(hir::QPath::Resolved(_, path))) => {
+                                self.tcx.sess.source_map().span_to_snippet(path.span).ok().map(
+                                    |p| format!("`{}` defined here returns `{}`", p, callee_ty),
+                                )
+                            }
+                            _ => Some(format!("`{}` defined here", callee_ty)),
                         };
-                        err.span_label(span, label);
+                        if let Some(label) = label {
+                            err.span_label(span, label);
+                        }
                     }
                     err.emit();
                 } else {
diff --git a/src/librustc_typeck/check/coercion.rs b/src/librustc_typeck/check/coercion.rs
index 33fc18b4b6e..2dc2a48ecbc 100644
--- a/src/librustc_typeck/check/coercion.rs
+++ b/src/librustc_typeck/check/coercion.rs
@@ -1402,9 +1402,12 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
                     {
                         // Are of this `impl Trait`'s traits object safe?
                         is_object_safe = bounds.iter().all(|bound| {
-                            bound.trait_def_id().map_or(false, |def_id| {
-                                fcx.tcx.object_safety_violations(def_id).is_empty()
-                            })
+                            bound
+                                .trait_ref()
+                                .and_then(|t| t.trait_def_id())
+                                .map_or(false, |def_id| {
+                                    fcx.tcx.object_safety_violations(def_id).is_empty()
+                                })
                         })
                     }
                 }
diff --git a/src/librustc_typeck/check/demand.rs b/src/librustc_typeck/check/demand.rs
index 0556c80e4f7..f7ffb5a2218 100644
--- a/src/librustc_typeck/check/demand.rs
+++ b/src/librustc_typeck/check/demand.rs
@@ -9,7 +9,7 @@ use rustc::ty::{self, AssocItem, Ty};
 use rustc_ast::util::parser::PREC_POSTFIX;
 use rustc_errors::{Applicability, DiagnosticBuilder};
 use rustc_hir as hir;
-use rustc_hir::{is_range_literal, print, Node};
+use rustc_hir::{is_range_literal, Node};
 use rustc_span::symbol::sym;
 use rustc_span::Span;
 
@@ -198,13 +198,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 .peekable();
 
             if compatible_variants.peek().is_some() {
-                let expr_text =
-                    self.tcx.sess.source_map().span_to_snippet(expr.span).unwrap_or_else(|_| {
-                        print::to_string(print::NO_ANN, |s| s.print_expr(expr))
-                    });
-                let suggestions = compatible_variants.map(|v| format!("{}({})", v, expr_text));
-                let msg = "try using a variant of the expected enum";
-                err.span_suggestions(expr.span, msg, suggestions, Applicability::MaybeIncorrect);
+                if let Ok(expr_text) = self.tcx.sess.source_map().span_to_snippet(expr.span) {
+                    let suggestions = compatible_variants.map(|v| format!("{}({})", v, expr_text));
+                    let msg = "try using a variant of the expected enum";
+                    err.span_suggestions(
+                        expr.span,
+                        msg,
+                        suggestions,
+                        Applicability::MaybeIncorrect,
+                    );
+                }
             }
         }
     }
diff --git a/src/librustc_typeck/check/expr.rs b/src/librustc_typeck/check/expr.rs
index dffed9a836c..53a20d9e867 100644
--- a/src/librustc_typeck/check/expr.rs
+++ b/src/librustc_typeck/check/expr.rs
@@ -475,7 +475,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 tcx.types.err
             }
             Res::Def(DefKind::Ctor(_, CtorKind::Fictive), _) => {
-                report_unexpected_variant_res(tcx, res, expr.span, qpath);
+                report_unexpected_variant_res(tcx, res, expr.span);
                 tcx.types.err
             }
             _ => self.instantiate_value_path(segs, opt_ty, res, expr.span, expr.hir_id).0,
@@ -696,10 +696,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     self,
                     &cause,
                     &mut |db| {
-                        db.span_label(
-                            fn_decl.output.span(),
-                            format!("expected `{}` because of this return type", fn_decl.output,),
-                        );
+                        let span = fn_decl.output.span();
+                        if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span) {
+                            db.span_label(
+                                span,
+                                format!("expected `{}` because of this return type", snippet),
+                            );
+                        }
                     },
                     true,
                 );
@@ -1668,20 +1671,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         if let (Some(len), Ok(user_index)) =
             (len.try_eval_usize(self.tcx, self.param_env), field.as_str().parse::<u64>())
         {
-            let base = self
-                .tcx
-                .sess
-                .source_map()
-                .span_to_snippet(base.span)
-                .unwrap_or_else(|_| self.tcx.hir().hir_to_pretty_string(base.hir_id));
-            let help = "instead of using tuple indexing, use array indexing";
-            let suggestion = format!("{}[{}]", base, field);
-            let applicability = if len < user_index {
-                Applicability::MachineApplicable
-            } else {
-                Applicability::MaybeIncorrect
-            };
-            err.span_suggestion(expr.span, help, suggestion, applicability);
+            if let Ok(base) = self.tcx.sess.source_map().span_to_snippet(base.span) {
+                let help = "instead of using tuple indexing, use array indexing";
+                let suggestion = format!("{}[{}]", base, field);
+                let applicability = if len < user_index {
+                    Applicability::MachineApplicable
+                } else {
+                    Applicability::MaybeIncorrect
+                };
+                err.span_suggestion(expr.span, help, suggestion, applicability);
+            }
         }
     }
 
@@ -1692,15 +1691,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         base: &hir::Expr<'_>,
         field: ast::Ident,
     ) {
-        let base = self
-            .tcx
-            .sess
-            .source_map()
-            .span_to_snippet(base.span)
-            .unwrap_or_else(|_| self.tcx.hir().hir_to_pretty_string(base.hir_id));
-        let msg = format!("`{}` is a raw pointer; try dereferencing it", base);
-        let suggestion = format!("(*{}).{}", base, field);
-        err.span_suggestion(expr.span, &msg, suggestion, Applicability::MaybeIncorrect);
+        if let Ok(base) = self.tcx.sess.source_map().span_to_snippet(base.span) {
+            let msg = format!("`{}` is a raw pointer; try dereferencing it", base);
+            let suggestion = format!("(*{}).{}", base, field);
+            err.span_suggestion(expr.span, &msg, suggestion, Applicability::MaybeIncorrect);
+        }
     }
 
     fn no_such_field_err<T: Display>(
diff --git a/src/librustc_typeck/check/method/suggest.rs b/src/librustc_typeck/check/method/suggest.rs
index e940ecce0b9..688820029fe 100644
--- a/src/librustc_typeck/check/method/suggest.rs
+++ b/src/librustc_typeck/check/method/suggest.rs
@@ -1061,7 +1061,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                 let trait_def_ids: FxHashSet<DefId> = param
                                     .bounds
                                     .iter()
-                                    .filter_map(|bound| bound.trait_def_id())
+                                    .filter_map(|bound| Some(bound.trait_ref()?.trait_def_id()?))
                                     .collect();
                                 if !candidates.iter().any(|t| trait_def_ids.contains(&t.def_id)) {
                                     err.span_suggestions(
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 91ab94bc684..f188ee0a13c 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -2677,14 +2677,14 @@ pub fn check_enum<'tcx>(
     check_transparent(tcx, sp, def_id);
 }
 
-fn report_unexpected_variant_res(tcx: TyCtxt<'_>, res: Res, span: Span, qpath: &QPath<'_>) {
+fn report_unexpected_variant_res(tcx: TyCtxt<'_>, res: Res, span: Span) {
     struct_span_err!(
         tcx.sess,
         span,
         E0533,
-        "expected unit struct, unit variant or constant, found {} `{}`",
+        "expected unit struct, unit variant or constant, found {}{}",
         res.descr(),
-        hir::print::to_string(&tcx.hir(), |s| s.print_qpath(qpath, false))
+        tcx.sess.source_map().span_to_snippet(span).map_or(String::new(), |s| format!(" `{}`", s)),
     )
     .emit();
 }
diff --git a/src/librustc_typeck/check/pat.rs b/src/librustc_typeck/check/pat.rs
index 0c4a05e6181..ec703d5ec9e 100644
--- a/src/librustc_typeck/check/pat.rs
+++ b/src/librustc_typeck/check/pat.rs
@@ -171,9 +171,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             PatKind::TupleStruct(ref qpath, subpats, ddpos) => {
                 self.check_pat_tuple_struct(pat, qpath, subpats, ddpos, expected, def_bm, ti)
             }
-            PatKind::Path(ref qpath) => {
-                self.check_pat_path(pat, path_res.unwrap(), qpath, expected, ti)
-            }
+            PatKind::Path(_) => self.check_pat_path(pat, path_res.unwrap(), expected, ti),
             PatKind::Struct(ref qpath, fields, etc) => {
                 self.check_pat_struct(pat, qpath, fields, etc, expected, def_bm, ti)
             }
@@ -694,7 +692,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         &self,
         pat: &Pat<'_>,
         path_resolution: (Res, Option<Ty<'tcx>>, &'b [hir::PathSegment<'b>]),
-        qpath: &hir::QPath<'_>,
         expected: Ty<'tcx>,
         ti: TopInfo<'tcx>,
     ) -> Ty<'tcx> {
@@ -707,17 +704,18 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 self.set_tainted_by_errors();
                 return tcx.types.err;
             }
-            Res::Def(DefKind::AssocFn, _)
-            | Res::Def(DefKind::Ctor(_, CtorKind::Fictive), _)
-            | Res::Def(DefKind::Ctor(_, CtorKind::Fn), _) => {
-                report_unexpected_variant_res(tcx, res, pat.span, qpath);
+            Res::Def(DefKind::AssocFn | DefKind::Ctor(_, CtorKind::Fictive | CtorKind::Fn), _) => {
+                report_unexpected_variant_res(tcx, res, pat.span);
                 return tcx.types.err;
             }
-            Res::Def(DefKind::Ctor(_, CtorKind::Const), _)
-            | Res::SelfCtor(..)
-            | Res::Def(DefKind::Const, _)
-            | Res::Def(DefKind::AssocConst, _)
-            | Res::Def(DefKind::ConstParam, _) => {} // OK
+            Res::SelfCtor(..)
+            | Res::Def(
+                DefKind::Ctor(_, CtorKind::Const)
+                | DefKind::Const
+                | DefKind::AssocConst
+                | DefKind::ConstParam,
+                _,
+            ) => {} // OK
             _ => bug!("unexpected pattern resolution: {:?}", res),
         }
 
@@ -791,14 +789,19 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             }
         };
         let report_unexpected_res = |res: Res| {
+            let sm = tcx.sess.source_map();
+            let path_str = sm
+                .span_to_snippet(sm.span_until_char(pat.span, '('))
+                .map_or(String::new(), |s| format!(" `{}`", s.trim_end()));
             let msg = format!(
-                "expected tuple struct or tuple variant, found {} `{}`",
+                "expected tuple struct or tuple variant, found {}{}",
                 res.descr(),
-                hir::print::to_string(&tcx.hir(), |s| s.print_qpath(qpath, false)),
+                path_str
             );
+
             let mut err = struct_span_err!(tcx.sess, pat.span, E0164, "{}", msg);
-            match (res, &pat.kind) {
-                (Res::Def(DefKind::Fn, _), _) | (Res::Def(DefKind::AssocFn, _), _) => {
+            match res {
+                Res::Def(DefKind::Fn | DefKind::AssocFn, _) => {
                     err.span_label(pat.span, "`fn` calls are not allowed in patterns");
                     err.help(
                         "for more information, visit \
diff --git a/src/librustc_typeck/check_unused.rs b/src/librustc_typeck/check_unused.rs
index d0414af5b21..9d8113e7b3f 100644
--- a/src/librustc_typeck/check_unused.rs
+++ b/src/librustc_typeck/check_unused.rs
@@ -5,7 +5,6 @@ use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, DefIdSet, LOCAL_CRATE};
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
-use rustc_hir::print::visibility_qualified;
 use rustc_session::lint;
 use rustc_span::Span;
 
@@ -176,16 +175,13 @@ fn unused_crates_lint(tcx: TyCtxt<'_>) {
                 Some(orig_name) => format!("use {} as {};", orig_name, item.ident.name),
                 None => format!("use {};", item.ident.name),
             };
-
-            let replacement = visibility_qualified(&item.vis, base_replacement);
-            let msg = "`extern crate` is not idiomatic in the new edition";
-            let help = format!("convert it to a `{}`", visibility_qualified(&item.vis, "use"));
-
-            lint.build(msg)
+            let vis = tcx.sess.source_map().span_to_snippet(item.vis.span).unwrap_or_default();
+            let add_vis = |to| if vis.is_empty() { to } else { format!("{} {}", vis, to) };
+            lint.build("`extern crate` is not idiomatic in the new edition")
                 .span_suggestion_short(
                     extern_crate.span,
-                    &help,
-                    replacement,
+                    &format!("convert it to a `{}`", add_vis("use".to_string())),
+                    add_vis(base_replacement),
                     Applicability::MachineApplicable,
                 )
                 .emit();
diff --git a/src/librustc_typeck/collect.rs b/src/librustc_typeck/collect.rs
index 42cd7246f08..31123c5cf02 100644
--- a/src/librustc_typeck/collect.rs
+++ b/src/librustc_typeck/collect.rs
@@ -2146,13 +2146,18 @@ fn compute_sig_of_foreign_fn_decl<'tcx>(
     {
         let check = |ast_ty: &hir::Ty<'_>, ty: Ty<'_>| {
             if ty.is_simd() {
+                let snip = tcx
+                    .sess
+                    .source_map()
+                    .span_to_snippet(ast_ty.span)
+                    .map_or(String::new(), |s| format!(" `{}`", s));
                 tcx.sess
                     .struct_span_err(
                         ast_ty.span,
                         &format!(
-                            "use of SIMD type `{}` in FFI is highly experimental and \
+                            "use of SIMD type{} in FFI is highly experimental and \
                              may result in invalid code",
-                            tcx.hir().hir_to_pretty_string(ast_ty.hir_id)
+                            snip
                         ),
                     )
                     .help("add `#![feature(simd_ffi)]` to the crate attributes to enable")
diff --git a/src/librustdoc/clean/inline.rs b/src/librustdoc/clean/inline.rs
index 153f7af9f97..510eae82834 100644
--- a/src/librustdoc/clean/inline.rs
+++ b/src/librustdoc/clean/inline.rs
@@ -482,8 +482,8 @@ fn build_module(cx: &DocContext<'_>, did: DefId, visited: &mut FxHashSet<DefId>)
 }
 
 pub fn print_inlined_const(cx: &DocContext<'_>, did: DefId) -> String {
-    if let Some(node_id) = cx.tcx.hir().as_local_hir_id(did) {
-        cx.tcx.hir().hir_to_pretty_string(node_id)
+    if let Some(hir_id) = cx.tcx.hir().as_local_hir_id(did) {
+        rustc_hir_pretty::id_to_string(&cx.tcx.hir(), hir_id)
     } else {
         cx.tcx.rendered_const(did)
     }
diff --git a/src/librustdoc/clean/utils.rs b/src/librustdoc/clean/utils.rs
index 82e34710f0c..b3bfb559749 100644
--- a/src/librustdoc/clean/utils.rs
+++ b/src/librustdoc/clean/utils.rs
@@ -578,7 +578,7 @@ pub fn print_const_expr(cx: &DocContext<'_>, body: hir::BodyId) -> String {
         None
     };
 
-    snippet.unwrap_or_else(|| cx.tcx.hir().hir_to_pretty_string(body.hir_id))
+    snippet.unwrap_or_else(|| rustc_hir_pretty::id_to_string(&cx.tcx.hir(), body.hir_id))
 }
 
 /// Given a type Path, resolve it to a Type using the TyCtxt
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 33cabad9193..3c5df0247c1 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -26,6 +26,7 @@ extern crate rustc_errors;
 extern crate rustc_expand;
 extern crate rustc_feature;
 extern crate rustc_hir;
+extern crate rustc_hir_pretty;
 extern crate rustc_index;
 extern crate rustc_infer;
 extern crate rustc_interface;
diff --git a/src/librustdoc/test.rs b/src/librustdoc/test.rs
index c5aa4677d56..93305a1f87a 100644
--- a/src/librustdoc/test.rs
+++ b/src/librustdoc/test.rs
@@ -910,7 +910,7 @@ impl<'a, 'hir> intravisit::Visitor<'hir> for HirCollector<'a, 'hir> {
 
     fn visit_item(&mut self, item: &'hir hir::Item) {
         let name = if let hir::ItemKind::Impl { ref self_ty, .. } = item.kind {
-            self.map.hir_to_pretty_string(self_ty.hir_id)
+            rustc_hir_pretty::id_to_string(&self.map, self_ty.hir_id)
         } else {
             item.ident.to_string()
         };
diff --git a/src/test/ui/methods/method-path-in-pattern.stderr b/src/test/ui/methods/method-path-in-pattern.stderr
index 1d1bdb6b052..ed3c0222c75 100644
--- a/src/test/ui/methods/method-path-in-pattern.stderr
+++ b/src/test/ui/methods/method-path-in-pattern.stderr
@@ -4,13 +4,13 @@ error[E0533]: expected unit struct, unit variant or constant, found associated f
 LL |         Foo::bar => {}
    |         ^^^^^^^^
 
-error[E0533]: expected unit struct, unit variant or constant, found associated function `Foo::bar`
+error[E0533]: expected unit struct, unit variant or constant, found associated function `<Foo>::bar`
   --> $DIR/method-path-in-pattern.rs:19:9
    |
 LL |         <Foo>::bar => {}
    |         ^^^^^^^^^^
 
-error[E0533]: expected unit struct, unit variant or constant, found associated function `Foo::trait_bar`
+error[E0533]: expected unit struct, unit variant or constant, found associated function `<Foo>::trait_bar`
   --> $DIR/method-path-in-pattern.rs:23:9
    |
 LL |         <Foo>::trait_bar => {}
@@ -22,7 +22,7 @@ error[E0533]: expected unit struct, unit variant or constant, found associated f
 LL |     if let Foo::bar = 0u32 {}
    |            ^^^^^^^^
 
-error[E0533]: expected unit struct, unit variant or constant, found associated function `Foo::bar`
+error[E0533]: expected unit struct, unit variant or constant, found associated function `<Foo>::bar`
   --> $DIR/method-path-in-pattern.rs:28:12
    |
 LL |     if let <Foo>::bar = 0u32 {}
diff --git a/src/test/ui/privacy/associated-item-privacy-trait.rs b/src/test/ui/privacy/associated-item-privacy-trait.rs
index 03347d5b99a..b1482bc040f 100644
--- a/src/test/ui/privacy/associated-item-privacy-trait.rs
+++ b/src/test/ui/privacy/associated-item-privacy-trait.rs
@@ -21,9 +21,9 @@ mod priv_trait {
         Pub.method();
         //~^ ERROR type `for<'r> fn(&'r Self) {<Self as priv_trait::PrivTr>::method}` is private
         <Pub as PrivTr>::CONST;
-        //~^ ERROR associated constant `PrivTr::CONST` is private
+        //~^ ERROR associated constant `<Pub as PrivTr>::CONST` is private
         let _: <Pub as PrivTr>::AssocTy;
-        //~^ ERROR associated type `PrivTr::AssocTy` is private
+        //~^ ERROR associated type `<Pub as PrivTr>::AssocTy` is private
         pub type InSignatureTy = <Pub as PrivTr>::AssocTy;
         //~^ ERROR trait `priv_trait::PrivTr` is private
         pub trait InSignatureTr: PrivTr {}
@@ -115,7 +115,7 @@ mod priv_parent_substs {
         <Priv as PubTr<_>>::CONST;
         //~^ ERROR type `priv_parent_substs::Priv` is private
 
-        let _: <Pub as PubTr>::AssocTy;  // FIXME no longer an error?!
+        let _: <Pub as PubTr>::AssocTy; // FIXME no longer an error?!
         let _: <Pub as PubTr<_>>::AssocTy;
         //~^ ERROR type `priv_parent_substs::Priv` is private
         let _: <Priv as PubTr<_>>::AssocTy;
diff --git a/src/test/ui/privacy/associated-item-privacy-trait.stderr b/src/test/ui/privacy/associated-item-privacy-trait.stderr
index c30cc947d45..b9f3e35d722 100644
--- a/src/test/ui/privacy/associated-item-privacy-trait.stderr
+++ b/src/test/ui/privacy/associated-item-privacy-trait.stderr
@@ -31,7 +31,7 @@ LL |     priv_trait::mac!();
    |
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: associated constant `PrivTr::CONST` is private
+error: associated constant `<Pub as PrivTr>::CONST` is private
   --> $DIR/associated-item-privacy-trait.rs:23:9
    |
 LL |         <Pub as PrivTr>::CONST;
@@ -42,7 +42,7 @@ LL |     priv_trait::mac!();
    |
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: associated type `PrivTr::AssocTy` is private
+error: associated type `<Pub as PrivTr>::AssocTy` is private
   --> $DIR/associated-item-privacy-trait.rs:25:16
    |
 LL |         let _: <Pub as PrivTr>::AssocTy;
diff --git a/src/test/ui/qualified/qualified-path-params.stderr b/src/test/ui/qualified/qualified-path-params.stderr
index 7ff43f4404c..4214e2503c3 100644
--- a/src/test/ui/qualified/qualified-path-params.stderr
+++ b/src/test/ui/qualified/qualified-path-params.stderr
@@ -1,4 +1,4 @@
-error[E0533]: expected unit struct, unit variant or constant, found associated function `<<S as Tr>::A>::f<u8>`
+error[E0533]: expected unit struct, unit variant or constant, found associated function `<S as Tr>::A::f::<u8>`
   --> $DIR/qualified-path-params.rs:20:9
    |
 LL |         <S as Tr>::A::f::<u8> => {}