Fix unused 'mut' warning for capture's root variable

3 files changed, 46 insertions, 17 deletions

diff --git a/src/test/ui/closures/2229_closure_analysis/run_pass/move_closure.rs b/src/test/ui/closures/2229_closure_analysis/run_pass/move_closure.rs
index 83ed1c28462..4007a5a48aa 100644
--- a/src/test/ui/closures/2229_closure_analysis/run_pass/move_closure.rs
+++ b/src/test/ui/closures/2229_closure_analysis/run_pass/move_closure.rs
@@ -29,19 +29,36 @@ fn struct_contains_ref_to_another_struct() {
     c();
 }
 
-fn no_ref() {
-    struct S(String);
-    struct T(S);
+#[derive(Debug)]
+struct S(String);
 
-    let t = T(S("s".into()));
+#[derive(Debug)]
+struct T(S);
+
+fn no_ref() {
+    let mut t = T(S("s".into()));
     let mut c = move || {
         t.0.0 = "new S".into();
     };
     c();
 }
 
+fn no_ref_nested() {
+    let mut t = T(S("s".into()));
+    let c = || {
+        println!("{:?}", t.0);
+        let mut c = move || {
+            t.0.0 = "new S".into();
+            println!("{:?}", t.0.0);
+        };
+        c();
+    };
+    c();
+}
+
 fn main() {
     simple_ref();
     struct_contains_ref_to_another_struct();
     no_ref();
+    no_ref_nested();
 }
diff --git a/src/test/ui/closures/2229_closure_analysis/run_pass/move_closure.stderr b/src/test/ui/closures/2229_closure_analysis/run_pass/move_closure.stderr
index 724b683bfbf..c1d8ba575d6 100644
--- a/src/test/ui/closures/2229_closure_analysis/run_pass/move_closure.stderr
+++ b/src/test/ui/closures/2229_closure_analysis/run_pass/move_closure.stderr
@@ -7,15 +7,5 @@ LL | #![feature(capture_disjoint_fields)]
    = note: `#[warn(incomplete_features)]` on by default
    = note: see issue #53488 <https://github.com/rust-lang/rust/issues/53488> for more information
 
-warning: variable does not need to be mutable
-  --> $DIR/move_closure.rs:36:9
-   |
-LL |     let mut t = T(S("s".into()));
-   |         ----^
-   |         |
-   |         help: remove this `mut`
-   |
-   = note: `#[warn(unused_mut)]` on by default
-
-warning: 2 warnings emitted
+warning: 1 warning emitted
 
diff --git a/src/test/ui/closures/2229_closure_analysis/run_pass/mut_ref_struct_mem.rs b/src/test/ui/closures/2229_closure_analysis/run_pass/mut_ref_struct_mem.rs
index 82e723cc825..2dba923647a 100644
--- a/src/test/ui/closures/2229_closure_analysis/run_pass/mut_ref_struct_mem.rs
+++ b/src/test/ui/closures/2229_closure_analysis/run_pass/mut_ref_struct_mem.rs
@@ -2,14 +2,14 @@
 
 // Test that we can mutate a place through a mut-borrow
 // that is captured by the closure
-//
+
 // More specifically we test that the if the mutable reference isn't root variable of a capture
 // but rather accessed while acessing the precise capture.
 
 #![feature(capture_disjoint_fields)]
 //~^ WARNING: the feature `capture_disjoint_fields` is incomplete
 
-fn main() {
+fn mut_tuple() {
     let mut t = (10, 10);
 
     let t1 = (&mut t, 10);
@@ -21,3 +21,25 @@ fn main() {
 
     c();
 }
+
+fn mut_tuple_nested() {
+    let mut t = (10, 10);
+
+    let t1 = (&mut t, 10);
+
+    let mut c = || {
+        let mut c = || {
+            // Mutable because (*t.0) is mutable
+            t1.0.0 += 10;
+        };
+
+        c();
+    };
+
+    c();
+}
+
+fn main() {
+    mut_tuple();
+    mut_tuple_nested();
+}