From bc9363376e0ae3dff683b67c035812ae274008af Mon Sep 17 00:00:00 2001
From: Max Taldykin <jorpic@gmail.com>
Date: Thu, 27 Dec 2018 20:11:25 +0300
Subject: [PATCH] Check pattern equality while checking declaration equality

---
 clippy_lints/src/utils/hir_utils.rs |  4 +++-
 tests/ui/copies.rs                  | 11 +++++++++++
 tests/ui/copies.stderr              | 24 ++++++++++++------------
 3 files changed, 26 insertions(+), 13 deletions(-)

diff --git a/clippy_lints/src/utils/hir_utils.rs b/clippy_lints/src/utils/hir_utils.rs
index 73169414a028..77f9dc6e5f1c 100644
--- a/clippy_lints/src/utils/hir_utils.rs
+++ b/clippy_lints/src/utils/hir_utils.rs
@@ -54,7 +54,9 @@ impl<'a, 'tcx: 'a> SpanlessEq<'a, 'tcx> {
         match (&left.node, &right.node) {
             (&StmtKind::Decl(ref l, _), &StmtKind::Decl(ref r, _)) => {
                 if let (&DeclKind::Local(ref l), &DeclKind::Local(ref r)) = (&l.node, &r.node) {
-                    both(&l.ty, &r.ty, |l, r| self.eq_ty(l, r)) && both(&l.init, &r.init, |l, r| self.eq_expr(l, r))
+                    self.eq_pat(&l.pat, &r.pat)
+                        && both(&l.ty, &r.ty, |l, r| self.eq_ty(l, r))
+                        && both(&l.init, &r.init, |l, r| self.eq_expr(l, r))
                 } else {
                     false
                 }
diff --git a/tests/ui/copies.rs b/tests/ui/copies.rs
index 00e1d726207a..43671c336fea 100644
--- a/tests/ui/copies.rs
+++ b/tests/ui/copies.rs
@@ -335,6 +335,17 @@ fn if_same_then_else() -> Result<&'static str, ()> {
         let foo = "";
         return Ok(&foo[0..]);
     }
+
+    // See #3559
+    if true {
+        let foo = "";
+        let (x, y) = (1, 2);
+        return Ok(&foo[x..y]);
+    } else {
+        let foo = "";
+        let (y, x) = (1, 2);
+        return Ok(&foo[x..y]);
+    }
 }
 
 #[warn(clippy::ifs_same_cond)]
diff --git a/tests/ui/copies.stderr b/tests/ui/copies.stderr
index e41fac0f6869..e69f2879aab4 100644
--- a/tests/ui/copies.stderr
+++ b/tests/ui/copies.stderr
@@ -352,40 +352,40 @@ note: same as this
     | |_____^
 
 error: this `if` has the same condition as a previous if
-   --> $DIR/copies.rs:347:15
+   --> $DIR/copies.rs:358:15
     |
-347 |     } else if b {
+358 |     } else if b {
     |               ^
     |
     = note: `-D clippy::ifs-same-cond` implied by `-D warnings`
 note: same as this
-   --> $DIR/copies.rs:346:8
+   --> $DIR/copies.rs:357:8
     |
-346 |     if b {
+357 |     if b {
     |        ^
 
 error: this `if` has the same condition as a previous if
-   --> $DIR/copies.rs:352:15
+   --> $DIR/copies.rs:363:15
     |
-352 |     } else if a == 1 {
+363 |     } else if a == 1 {
     |               ^^^^^^
     |
 note: same as this
-   --> $DIR/copies.rs:351:8
+   --> $DIR/copies.rs:362:8
     |
-351 |     if a == 1 {
+362 |     if a == 1 {
     |        ^^^^^^
 
 error: this `if` has the same condition as a previous if
-   --> $DIR/copies.rs:358:15
+   --> $DIR/copies.rs:369:15
     |
-358 |     } else if 2 * a == 1 {
+369 |     } else if 2 * a == 1 {
     |               ^^^^^^^^^^
     |
 note: same as this
-   --> $DIR/copies.rs:356:8
+   --> $DIR/copies.rs:367:8
     |
-356 |     if 2 * a == 1 {
+367 |     if 2 * a == 1 {
     |        ^^^^^^^^^^
 
 error: aborting due to 20 previous errors