From cecfdeab196f30cf12bfa757e3e15ce9e3417689 Mon Sep 17 00:00:00 2001
From: flip1995 <uwdkn@student.kit.edu>
Date: Tue, 3 Apr 2018 16:41:30 +0200
Subject: [PATCH] Don't trigger while_immutable_condition for mutable fields of
 tuples/structs

---
 clippy_lints/src/loops.rs     | 12 ++++++------
 tests/ui/infinite_loop.rs     |  6 ++++++
 tests/ui/infinite_loop.stderr | 24 ++++++++++++------------
 3 files changed, 24 insertions(+), 18 deletions(-)

diff --git a/clippy_lints/src/loops.rs b/clippy_lints/src/loops.rs
index 6f04940ae31..9a6b7627b47 100644
--- a/clippy_lints/src/loops.rs
+++ b/clippy_lints/src/loops.rs
@@ -2237,7 +2237,7 @@ struct MutVarsDelegate {
 }
 
 impl<'tcx> MutVarsDelegate {
-    fn update(&mut self, cat: &'tcx Categorization, sp: Span) {
+    fn update(&mut self, cat: &'tcx Categorization) {
         match *cat {
             Categorization::Local(id) =>
                 if let Some(used) = self.used_mutably.get_mut(&id) {
@@ -2249,7 +2249,7 @@ impl<'tcx> MutVarsDelegate {
                 //`while`-body, not just the ones in the condition.
                 self.skip = true
             },
-            Categorization::Deref(ref cmt, _) => self.update(&cmt.cat, sp),
+            Categorization::Deref(ref cmt, _) | Categorization::Interior(ref cmt, _) => self.update(&cmt.cat),
             _ => {}
         }
     }
@@ -2263,14 +2263,14 @@ impl<'tcx> Delegate<'tcx> for MutVarsDelegate {
 
     fn consume_pat(&mut self, _: &Pat, _: cmt<'tcx>, _: ConsumeMode) {}
 
-    fn borrow(&mut self, _: NodeId, sp: Span, cmt: cmt<'tcx>, _: ty::Region, bk: ty::BorrowKind, _: LoanCause) {
+    fn borrow(&mut self, _: NodeId, _: Span, cmt: cmt<'tcx>, _: ty::Region, bk: ty::BorrowKind, _: LoanCause) {
         if let ty::BorrowKind::MutBorrow = bk {
-            self.update(&cmt.cat, sp)
+            self.update(&cmt.cat)
         }
     }
 
-    fn mutate(&mut self, _: NodeId, sp: Span, cmt: cmt<'tcx>, _: MutateMode) {
-        self.update(&cmt.cat, sp)
+    fn mutate(&mut self, _: NodeId, _: Span, cmt: cmt<'tcx>, _: MutateMode) {
+        self.update(&cmt.cat)
     }
 
     fn decl_without_init(&mut self, _: NodeId, _: Span) {}
diff --git a/tests/ui/infinite_loop.rs b/tests/ui/infinite_loop.rs
index 4029f9a9b29..353d34134eb 100644
--- a/tests/ui/infinite_loop.rs
+++ b/tests/ui/infinite_loop.rs
@@ -55,6 +55,12 @@ fn immutable_condition() {
         }
     };
     c();
+
+    let mut tup = (0, 0);
+    while tup.0 < 5 {
+        tup.0 += 1;
+        println!("OK - tup.0 gets mutated")
+    }
 }
 
 fn unused_var() {
diff --git a/tests/ui/infinite_loop.stderr b/tests/ui/infinite_loop.stderr
index d24fd925e6d..26ec9582fb4 100644
--- a/tests/ui/infinite_loop.stderr
+++ b/tests/ui/infinite_loop.stderr
@@ -19,39 +19,39 @@ error: Variable in the condition are not mutated in the loop body. This either l
    |           ^^^^^
 
 error: Variable in the condition are not mutated in the loop body. This either leads to an infinite or to a never running loop.
-  --> $DIR/infinite_loop.rs:64:11
+  --> $DIR/infinite_loop.rs:70:11
    |
-64 |     while i < 3 {
+70 |     while i < 3 {
    |           ^^^^^
 
 error: Variable in the condition are not mutated in the loop body. This either leads to an infinite or to a never running loop.
-  --> $DIR/infinite_loop.rs:69:11
+  --> $DIR/infinite_loop.rs:75:11
    |
-69 |     while i < 3 && j > 0 {
+75 |     while i < 3 && j > 0 {
    |           ^^^^^^^^^^^^^^
 
 error: Variable in the condition are not mutated in the loop body. This either leads to an infinite or to a never running loop.
-  --> $DIR/infinite_loop.rs:73:11
+  --> $DIR/infinite_loop.rs:79:11
    |
-73 |     while i < 3 {
+79 |     while i < 3 {
    |           ^^^^^
 
 error: Variable in the condition are not mutated in the loop body. This either leads to an infinite or to a never running loop.
-  --> $DIR/infinite_loop.rs:88:11
+  --> $DIR/infinite_loop.rs:94:11
    |
-88 |     while i < 3 {
+94 |     while i < 3 {
    |           ^^^^^
 
 error: Variable in the condition are not mutated in the loop body. This either leads to an infinite or to a never running loop.
-  --> $DIR/infinite_loop.rs:93:11
+  --> $DIR/infinite_loop.rs:99:11
    |
-93 |     while i < 3 {
+99 |     while i < 3 {
    |           ^^^^^
 
 error: Variable in the condition are not mutated in the loop body. This either leads to an infinite or to a never running loop.
-   --> $DIR/infinite_loop.rs:156:15
+   --> $DIR/infinite_loop.rs:162:15
     |
-156 |         while self.count < n {
+162 |         while self.count < n {
     |               ^^^^^^^^^^^^^^
 
 error: aborting due to 9 previous errors