From ff2fc39b1affc0a9b47d7436df616eacae2b4cb0 Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Sat, 1 Jun 2019 14:16:15 +0400
Subject: [PATCH 1/2] RFC: Make `..` a pattern syntactically

---
 text/0000-dotdot-patterns.md | 96 ++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 text/0000-dotdot-patterns.md

diff --git a/text/0000-dotdot-patterns.md b/text/0000-dotdot-patterns.md
new file mode 100644
index 00000000000..64f5eb6c24d
--- /dev/null
+++ b/text/0000-dotdot-patterns.md
@@ -0,0 +1,96 @@
+- Feature Name: `dotdot_patterns`
+- Start Date: 2019-06-01
+- RFC PR: [rust-lang/rfcs#0000](https://github.com/rust-lang/rfcs/pull/0000)
+- Rust Issue: [rust-lang/rust#0000](https://github.com/rust-lang/rust/issues/0000)
+
+# Summary
+[summary]: #summary
+
+Make `..` a pattern rather than a syntactic fragment of some other patterns.
+
+# Motivation
+[motivation]: #motivation
+
+The change simplifies pattern grammar and simplifies use of `..` in macros.  
+In particular, the `pat` macro matcher will now accept `..` and `IDENT @ ..`.
+
+# Guide-level explanation
+[guide-level-explanation]: #guide-level-explanation
+
+`..` becomes a pattern syntacticaly.
+The notable consequences of this are listed below.
+
+- `pat` macro matcher will now accept `..` and more complex pattern containing `..`,
+for example `ref x @ ..`.
+
+- A trailing comma is accepted after `..` in tuple struct, tuple or slice pattern.
+```rust
+Variant(a, b, ..,) // OK
+```
+
+- Some nonsensical code can now be accepted under `cfg(FALSE)`.
+```rust
+#[cfg(FALSE)]
+Tuple(.., a, ..) // OK
+```
+
+`..` in "inappropriate" positions is still rejected semantically.
+```rust
+let .. = 10; // Semantic error, `..` is not a part of a "list" pattern
+let Option(.., ..) = 11; // Semantic error, multiple `..`s in a single "list" pattern
+```
+
+# Reference-level explanation
+[reference-level-explanation]: #reference-level-explanation
+
+Pattern grammar is extended with a new production
+```
+PAT = ..
+```
+Special productions allowing `..` in tuple struct, tuple and slice patterns are subsumed by this
+new production and removed.
+
+Semantically, the `..` pattern is accepted
+- Immediately inside a tuple struct/variant pattern `Tuple(PAT, .., PAT)`
+- Immediately inside a tuple pattern `(PAT, .., PAT)`
+- Immediately inside a slice pattern `[PAT, .., PAT]`.
+- Immediately inside a binding pattern inside a slice pattern `[PAT, BINDING @ .., PAT]`.
+
+An error is produced if this pattern is used in any other position.
+
+An error is produced if more that one `..` or `BINDING @ ..` pattern is used inside its containing
+tuple struct / tuple / slice pattern.
+
+`(..)` is still a tuple pattern and not a parenthesized `..` pattern for backward compatibility.
+
+Note that `..` in struct patterns
+```rust
+Struct { field1: PAT, field2, .. }
+```
+is still not a pattern, but a fragment of a struct pattern syntax.
+
+# Drawbacks
+[drawbacks]: #drawbacks
+
+More meaningless code may be accepted under `cfg(FALSE)` where semantic checks are not performed.
+
+# Rationale and alternatives
+[rationale-and-alternatives]: #rationale-and-alternatives
+
+See "Motivation" for the rationale.  
+Status quo is always an alternative.
+
+# Prior art
+[prior-art]: #prior-art
+
+This RFC is a follow up to https://github.com/rust-lang/rfcs/pull/2359.
+
+# Unresolved questions
+[unresolved-questions]: #unresolved-questions
+
+None so far.
+
+# Future possibilities
+[future-possibilities]: #future-possibilities
+
+Accept `BINDING @ ..` in tuple patterns, `(head, tail @ ..)`.

From 52bb5b6be878db9db46b4622e3224b4954167331 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Sun, 30 Jun 2019 23:08:19 +0200
Subject: [PATCH 2/2] RFC 2707

---
 text/{0000-dotdot-patterns.md => 2707-dotdot-patterns.md} | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
 rename text/{0000-dotdot-patterns.md => 2707-dotdot-patterns.md} (94%)

diff --git a/text/0000-dotdot-patterns.md b/text/2707-dotdot-patterns.md
similarity index 94%
rename from text/0000-dotdot-patterns.md
rename to text/2707-dotdot-patterns.md
index 64f5eb6c24d..10b1428d65f 100644
--- a/text/0000-dotdot-patterns.md
+++ b/text/2707-dotdot-patterns.md
@@ -1,7 +1,7 @@
 - Feature Name: `dotdot_patterns`
 - Start Date: 2019-06-01
-- RFC PR: [rust-lang/rfcs#0000](https://github.com/rust-lang/rfcs/pull/0000)
-- Rust Issue: [rust-lang/rust#0000](https://github.com/rust-lang/rust/issues/0000)
+- RFC PR: [rust-lang/rfcs#2707](https://github.com/rust-lang/rfcs/pull/2707)
+- Rust Issue: [rust-lang/rust#62254](https://github.com/rust-lang/rust/issues/62254)
 
 # Summary
 [summary]: #summary