Auto merge of #32202 - arielb1:slice-patterns, r=nikomatsakis

Implement RFC495 semantics for slice patterns

non-MIR translation is still not supported for these and will happily ICE.

This is a [breaking-change] for many uses of slice_patterns.

[RFC 495 text](https://github.com/rust-lang/rfcs/blob/master/text/0495-array-pattern-changes.md)

2 files changed, 9 insertions, 7 deletions

diff --git a/src/librustdoc/clean/inline.rs b/src/librustdoc/clean/inline.rs
index f5d54123f37..f5ca125aca9 100644
--- a/src/librustdoc/clean/inline.rs
+++ b/src/librustdoc/clean/inline.rs
@@ -22,6 +22,7 @@ use rustc::hir::def_id::DefId;
 use rustc::hir::print as pprust;
 use rustc::ty::{self, TyCtxt};
 use rustc::ty::subst;
+use rustc::util::common::slice_pat;
 
 use rustc_const_eval::lookup_const_by_id;
 
@@ -197,10 +198,10 @@ fn build_struct<'a, 'tcx>(cx: &DocContext, tcx: TyCtxt<'a, 'tcx, 'tcx>,
     let variant = tcx.lookup_adt_def(did).struct_variant();
 
     clean::Struct {
-        struct_type: match &*variant.fields {
-            [] => doctree::Unit,
-            [_] if variant.kind == ty::VariantKind::Tuple => doctree::Newtype,
-            [..] if variant.kind == ty::VariantKind::Tuple => doctree::Tuple,
+        struct_type: match slice_pat(&&*variant.fields) {
+            &[] => doctree::Unit,
+            &[_] if variant.kind == ty::VariantKind::Tuple => doctree::Newtype,
+            &[..] if variant.kind == ty::VariantKind::Tuple => doctree::Tuple,
             _ => doctree::Plain,
         },
         generics: (&t.generics, &predicates, subst::TypeSpace).clean(cx),
diff --git a/src/librustdoc/html/format.rs b/src/librustdoc/html/format.rs
index 92401a5c55f..760e84622cf 100644
--- a/src/librustdoc/html/format.rs
+++ b/src/librustdoc/html/format.rs
@@ -20,6 +20,7 @@ use std::iter::repeat;
 
 use rustc::middle::cstore::LOCAL_CRATE;
 use rustc::hir::def_id::{CRATE_DEF_INDEX, DefId};
+use rustc::util::common::slice_pat;
 use syntax::abi::Abi;
 use rustc::hir;
 
@@ -474,9 +475,9 @@ impl fmt::Display for clean::Type {
                        decl.decl)
             }
             clean::Tuple(ref typs) => {
-                match &**typs {
-                    [] => primitive_link(f, clean::PrimitiveTuple, "()"),
-                    [ref one] => {
+                match slice_pat(&&**typs) {
+                    &[] => primitive_link(f, clean::PrimitiveTuple, "()"),
+                    &[ref one] => {
                         primitive_link(f, clean::PrimitiveTuple, "(")?;
                         write!(f, "{},", one)?;
                         primitive_link(f, clean::PrimitiveTuple, ")")