Auto merge of #68101 - JohnTitor:rollup-mvmjukr, r=JohnTitor

Rollup of 8 pull requests

Successful merges:

 - #66045 (Add method Result::into_ok)
 - #67258 (Introduce `X..`, `..X`, and `..=X` range patterns)
 - #68014 (Unify output of "variant not found" errors)
 - #68019 (Build compiletest with in-tree libtest)
 - #68039 (remove explicit strip-hidden pass from compiler doc generation)
 - #68050 (Canonicalize rustc_error imports)
 - #68059 (Allow specifying LLVM args in target specifications)
 - #68075 (rustbuild: Cleanup book generation)

Failed merges:

 - #68089 (Unstabilize `Vec::remove_item`)

r? @ghost

10 files changed, 19 insertions, 15 deletions

diff --git a/src/libsyntax/Cargo.toml b/src/libsyntax/Cargo.toml
index e4f0398fb42..7d9f715e9fe 100644
--- a/src/libsyntax/Cargo.toml
+++ b/src/libsyntax/Cargo.toml
@@ -13,8 +13,8 @@ doctest = false
 rustc_serialize = { path = "../libserialize", package = "serialize" }
 log = "0.4"
 scoped-tls = "1.0"
+rustc_errors = { path = "../librustc_errors" }
 rustc_span = { path = "../librustc_span" }
-errors = { path = "../librustc_errors", package = "rustc_errors" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_feature = { path = "../librustc_feature" }
 rustc_index = { path = "../librustc_index" }
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 1d3bb7d8768..33acba8eba0 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -649,7 +649,7 @@ pub enum PatKind {
     Lit(P<Expr>),
 
     /// A range pattern (e.g., `1...2`, `1..=2` or `1..2`).
-    Range(P<Expr>, P<Expr>, Spanned<RangeEnd>),
+    Range(Option<P<Expr>>, Option<P<Expr>>, Spanned<RangeEnd>),
 
     /// A slice pattern `[a, b, c]`.
     Slice(Vec<P<Pat>>),
diff --git a/src/libsyntax/attr/builtin.rs b/src/libsyntax/attr/builtin.rs
index b308d479545..958e4373cc0 100644
--- a/src/libsyntax/attr/builtin.rs
+++ b/src/libsyntax/attr/builtin.rs
@@ -6,7 +6,7 @@ use crate::feature_gate::feature_err;
 use crate::print::pprust;
 use crate::sess::ParseSess;
 
-use errors::{struct_span_err, Applicability, Handler};
+use rustc_errors::{struct_span_err, Applicability, Handler};
 use rustc_feature::{find_gated_cfg, is_builtin_attr_name, Features, GatedCfg};
 use rustc_macros::HashStable_Generic;
 use rustc_span::hygiene::Transparency;
diff --git a/src/libsyntax/attr/mod.rs b/src/libsyntax/attr/mod.rs
index 8449b61f7b0..ec05dab451a 100644
--- a/src/libsyntax/attr/mod.rs
+++ b/src/libsyntax/attr/mod.rs
@@ -384,7 +384,7 @@ pub fn find_by_name(attrs: &[Attribute], name: Symbol) -> Option<&Attribute> {
 
 pub fn allow_internal_unstable<'a>(
     attrs: &[Attribute],
-    span_diagnostic: &'a errors::Handler,
+    span_diagnostic: &'a rustc_errors::Handler,
 ) -> Option<impl Iterator<Item = Symbol> + 'a> {
     find_by_name(attrs, sym::allow_internal_unstable).and_then(|attr| {
         attr.meta_item_list()
diff --git a/src/libsyntax/feature_gate/check.rs b/src/libsyntax/feature_gate/check.rs
index 52eb20d320f..4eee4e943c2 100644
--- a/src/libsyntax/feature_gate/check.rs
+++ b/src/libsyntax/feature_gate/check.rs
@@ -4,9 +4,9 @@ use crate::attr;
 use crate::sess::ParseSess;
 use crate::visit::{self, FnKind, Visitor};
 
-use errors::{error_code, struct_span_err, Applicability, DiagnosticBuilder, Handler};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_error_codes::*;
+use rustc_errors::{error_code, struct_span_err, Applicability, DiagnosticBuilder, Handler};
 use rustc_feature::{find_feature_issue, GateIssue};
 use rustc_feature::{AttributeGate, BUILTIN_ATTRIBUTE_MAP};
 use rustc_feature::{Feature, Features, State as FeatureState, UnstableFeatures};
@@ -911,6 +911,7 @@ pub fn check_crate(
     gate_all!(raw_ref_op, "raw address of syntax is experimental");
     gate_all!(const_trait_bound_opt_out, "`?const` on trait bounds is experimental");
     gate_all!(const_trait_impl, "const trait impls are experimental");
+    gate_all!(half_open_range_patterns, "half-open range patterns are unstable");
 
     // All uses of `gate_all!` below this point were added in #65742,
     // and subsequently disabled (with the non-early gating readded).
diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index b197eab7394..7ee4ca4603c 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -18,7 +18,6 @@
 #![recursion_limit = "256"]
 
 use ast::AttrId;
-pub use errors;
 use rustc_data_structures::sync::Lock;
 use rustc_index::bit_set::GrowableBitSet;
 use rustc_span::edition::{Edition, DEFAULT_EDITION};
diff --git a/src/libsyntax/mut_visit.rs b/src/libsyntax/mut_visit.rs
index 264ba25cede..58d4e46111b 100644
--- a/src/libsyntax/mut_visit.rs
+++ b/src/libsyntax/mut_visit.rs
@@ -1075,8 +1075,8 @@ pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
         PatKind::Box(inner) => vis.visit_pat(inner),
         PatKind::Ref(inner, _mutbl) => vis.visit_pat(inner),
         PatKind::Range(e1, e2, Spanned { span: _, node: _ }) => {
-            vis.visit_expr(e1);
-            vis.visit_expr(e2);
+            visit_opt(e1, |e| vis.visit_expr(e));
+            visit_opt(e2, |e| vis.visit_expr(e));
             vis.visit_span(span);
         }
         PatKind::Tuple(elems) | PatKind::Slice(elems) | PatKind::Or(elems) => {
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index dd9976510dc..11c8cb8ef75 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -2329,14 +2329,18 @@ impl<'a> State<'a> {
             }
             PatKind::Lit(ref e) => self.print_expr(&**e),
             PatKind::Range(ref begin, ref end, Spanned { node: ref end_kind, .. }) => {
-                self.print_expr(begin);
-                self.s.space();
+                if let Some(e) = begin {
+                    self.print_expr(e);
+                    self.s.space();
+                }
                 match *end_kind {
                     RangeEnd::Included(RangeSyntax::DotDotDot) => self.s.word("..."),
                     RangeEnd::Included(RangeSyntax::DotDotEq) => self.s.word("..="),
                     RangeEnd::Excluded => self.s.word(".."),
                 }
-                self.print_expr(end);
+                if let Some(e) = end {
+                    self.print_expr(e);
+                }
             }
             PatKind::Slice(ref elts) => {
                 self.s.word("[");
diff --git a/src/libsyntax/show_span.rs b/src/libsyntax/show_span.rs
index fb641239dfa..b70e2ce0d3e 100644
--- a/src/libsyntax/show_span.rs
+++ b/src/libsyntax/show_span.rs
@@ -29,7 +29,7 @@ impl FromStr for Mode {
 }
 
 struct ShowSpanVisitor<'a> {
-    span_diagnostic: &'a errors::Handler,
+    span_diagnostic: &'a rustc_errors::Handler,
     mode: Mode,
 }
 
@@ -60,7 +60,7 @@ impl<'a> Visitor<'a> for ShowSpanVisitor<'a> {
     }
 }
 
-pub fn run(span_diagnostic: &errors::Handler, mode: &str, krate: &ast::Crate) {
+pub fn run(span_diagnostic: &rustc_errors::Handler, mode: &str, krate: &ast::Crate) {
     let mode = match mode.parse().ok() {
         Some(mode) => mode,
         None => return,
diff --git a/src/libsyntax/visit.rs b/src/libsyntax/visit.rs
index ebb49abebb0..3c2ebacbc4e 100644
--- a/src/libsyntax/visit.rs
+++ b/src/libsyntax/visit.rs
@@ -492,8 +492,8 @@ pub fn walk_pat<'a, V: Visitor<'a>>(visitor: &mut V, pattern: &'a Pat) {
         }
         PatKind::Lit(ref expression) => visitor.visit_expr(expression),
         PatKind::Range(ref lower_bound, ref upper_bound, _) => {
-            visitor.visit_expr(lower_bound);
-            visitor.visit_expr(upper_bound);
+            walk_list!(visitor, visit_expr, lower_bound);
+            walk_list!(visitor, visit_expr, upper_bound);
         }
         PatKind::Wild | PatKind::Rest => {}
         PatKind::Tuple(ref elems) | PatKind::Slice(ref elems) | PatKind::Or(ref elems) => {