From e84efc4a4656e54a4f08b99592d5d98ac5726449 Mon Sep 17 00:00:00 2001
From: Dawer <7803845+iDawer@users.noreply.github.com>
Date: Tue, 11 May 2021 17:18:16 +0500
Subject: Replace the old match checking algorithm

---
 .../hir_ty/src/diagnostics/match_check/pat_util.rs | 52 ++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 crates/hir_ty/src/diagnostics/match_check/pat_util.rs

(limited to 'crates/hir_ty/src/diagnostics/match_check/pat_util.rs')

diff --git a/crates/hir_ty/src/diagnostics/match_check/pat_util.rs b/crates/hir_ty/src/diagnostics/match_check/pat_util.rs
new file mode 100644
index 000000000..eb0b07a52
--- /dev/null
+++ b/crates/hir_ty/src/diagnostics/match_check/pat_util.rs
@@ -0,0 +1,52 @@
+use std::iter::{Enumerate, ExactSizeIterator};
+
+pub(crate) struct EnumerateAndAdjust<I> {
+    enumerate: Enumerate<I>,
+    gap_pos: usize,
+    gap_len: usize,
+}
+
+impl<I> Iterator for EnumerateAndAdjust<I>
+where
+    I: Iterator,
+{
+    type Item = (usize, <I as Iterator>::Item);
+
+    fn next(&mut self) -> Option<(usize, <I as Iterator>::Item)> {
+        self.enumerate
+            .next()
+            .map(|(i, elem)| (if i < self.gap_pos { i } else { i + self.gap_len }, elem))
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.enumerate.size_hint()
+    }
+}
+
+pub(crate) trait EnumerateAndAdjustIterator {
+    fn enumerate_and_adjust(
+        self,
+        expected_len: usize,
+        gap_pos: Option<usize>,
+    ) -> EnumerateAndAdjust<Self>
+    where
+        Self: Sized;
+}
+
+impl<T: ExactSizeIterator> EnumerateAndAdjustIterator for T {
+    fn enumerate_and_adjust(
+        self,
+        expected_len: usize,
+        gap_pos: Option<usize>,
+    ) -> EnumerateAndAdjust<Self>
+    where
+        Self: Sized,
+    {
+        let actual_len = self.len();
+        EnumerateAndAdjust {
+            enumerate: self.enumerate(),
+            gap_pos: gap_pos.unwrap_or(expected_len),
+            gap_len: expected_len - actual_len,
+        }
+    }
+}
-- 
cgit v1.2.3


From f571b62a13aff662c9d1c17206342479f8529633 Mon Sep 17 00:00:00 2001
From: Dawer <7803845+iDawer@users.noreply.github.com>
Date: Sun, 16 May 2021 18:11:45 +0500
Subject: minor: doc comment pat_util

---
 crates/hir_ty/src/diagnostics/match_check/pat_util.rs | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'crates/hir_ty/src/diagnostics/match_check/pat_util.rs')

diff --git a/crates/hir_ty/src/diagnostics/match_check/pat_util.rs b/crates/hir_ty/src/diagnostics/match_check/pat_util.rs
index eb0b07a52..b89b4f2bf 100644
--- a/crates/hir_ty/src/diagnostics/match_check/pat_util.rs
+++ b/crates/hir_ty/src/diagnostics/match_check/pat_util.rs
@@ -1,3 +1,7 @@
+//! Pattern untilities.
+//!
+//! Originates from `rustc_hir::pat_util`
+
 use std::iter::{Enumerate, ExactSizeIterator};
 
 pub(crate) struct EnumerateAndAdjust<I> {
-- 
cgit v1.2.3