Closure capture borrow diagnostics for disjoint captures

17 files changed, 264 insertions, 12 deletions

diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-1.rs b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-1.rs
new file mode 100644
index 00000000000..2f3358dcd8d
--- /dev/null
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-1.rs
@@ -0,0 +1,20 @@
+#![feature(capture_disjoint_fields)]
+//~^ WARNING: the feature `capture_disjoint_fields` is incomplete
+
+#[derive(Debug)]
+struct Point {
+    x: i32,
+    y: i32,
+}
+fn main() {
+    let mut p = Point {x: 1, y: 2 };
+
+    let y = &mut p.y;
+    let mut c = || {
+    //~^ ERROR cannot borrow `p` as mutable more than once at a time
+       let x = &mut p.x;
+       println!("{:?}", p);
+    };
+    c();
+    *y+=1;
+}
diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-1.stderr b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-1.stderr
new file mode 100644
index 00000000000..e15067b264d
--- /dev/null
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-1.stderr
@@ -0,0 +1,28 @@
+warning: the feature `capture_disjoint_fields` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/borrowck-1.rs:1:12
+   |
+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
+
+error[E0499]: cannot borrow `p` as mutable more than once at a time
+  --> $DIR/borrowck-1.rs:13:17
+   |
+LL |     let y = &mut p.y;
+   |             -------- first mutable borrow occurs here
+LL |     let mut c = || {
+   |                 ^^ second mutable borrow occurs here
+LL |
+LL |        let x = &mut p.x;
+   |                     --- capture is mutable because of use here
+LL |        println!("{:?}", p);
+   |                         - second borrow occurs due to use of `p` in closure
+...
+LL |     *y+=1;
+   |     ----- first borrow later used here
+
+error: aborting due to previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0499`.
diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-2.rs b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-2.rs
new file mode 100644
index 00000000000..06c6a87eb10
--- /dev/null
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-2.rs
@@ -0,0 +1,20 @@
+#![feature(capture_disjoint_fields)]
+//~^ WARNING: the feature `capture_disjoint_fields` is incomplete
+
+#[derive(Debug)]
+struct Point {
+    x: i32,
+    y: i32,
+}
+fn main() {
+    let mut p = Point {x: 1, y: 2 };
+
+    let y = &p.y;
+    let mut c = || {
+    //~^ ERROR cannot borrow `p` as mutable because it is also borrowed as immutable
+       println!("{:?}", p);
+       let x = &mut p.x;
+    };
+    c();
+    println!("{}", y);
+}
diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-2.stderr b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-2.stderr
new file mode 100644
index 00000000000..a195b981eaa
--- /dev/null
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-2.stderr
@@ -0,0 +1,28 @@
+warning: the feature `capture_disjoint_fields` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/borrowck-2.rs:1:12
+   |
+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
+
+error[E0502]: cannot borrow `p` as mutable because it is also borrowed as immutable
+  --> $DIR/borrowck-2.rs:13:17
+   |
+LL |     let y = &p.y;
+   |             ---- immutable borrow occurs here
+LL |     let mut c = || {
+   |                 ^^ mutable borrow occurs here
+LL |
+LL |        println!("{:?}", p);
+   |                         - second borrow occurs due to use of `p` in closure
+LL |        let x = &mut p.x;
+   |                     --- capture is mutable because of use here
+...
+LL |     println!("{}", y);
+   |                    - immutable borrow later used here
+
+error: aborting due to previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0502`.
diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-3.rs b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-3.rs
new file mode 100644
index 00000000000..ba998f78c87
--- /dev/null
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-3.rs
@@ -0,0 +1,19 @@
+#![feature(capture_disjoint_fields)]
+//~^ WARNING: the feature `capture_disjoint_fields` is incomplete
+
+#[derive(Debug)]
+struct Point {
+    x: String,
+    y: String,
+}
+fn main() {
+    let mut c = {
+        let mut p = Point {x: "1".to_string(), y: "2".to_string() };
+        || {
+           let x = &mut p.x;
+           println!("{:?}", p);
+            //~^ ERROR `p` does not live long enough
+        }
+    };
+    c();
+}
diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-3.stderr b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-3.stderr
new file mode 100644
index 00000000000..b54c729a307
--- /dev/null
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-3.stderr
@@ -0,0 +1,27 @@
+warning: the feature `capture_disjoint_fields` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/borrowck-3.rs:1:12
+   |
+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
+
+error[E0597]: `p` does not live long enough
+  --> $DIR/borrowck-3.rs:14:29
+   |
+LL |     let mut c = {
+   |         ----- borrow later stored here
+LL |         let mut p = Point {x: "1".to_string(), y: "2".to_string() };
+LL |         || {
+   |         -- value captured here
+LL |            let x = &mut p.x;
+LL |            println!("{:?}", p);
+   |                             ^ borrowed value does not live long enough
+...
+LL |     };
+   |     - `p` dropped here while still borrowed
+
+error: aborting due to previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0597`.
diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-4.rs b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-4.rs
new file mode 100644
index 00000000000..4fab0189c27
--- /dev/null
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-4.rs
@@ -0,0 +1,21 @@
+#![feature(capture_disjoint_fields)]
+//~^ WARNING: the feature `capture_disjoint_fields` is incomplete
+
+#[derive(Debug)]
+struct Point {
+    x: i32,
+    y: i32,
+}
+fn foo () -> impl FnMut()->() {
+    let mut p = Point {x: 1, y: 2 };
+    let mut c = || {
+    //~^ ERROR closure may outlive the current function, but it borrows `p`
+       p.x+=5;
+       println!("{:?}", p);
+    };
+    c
+}
+fn main() {
+    let c = foo();
+    c();
+}
diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-4.stderr b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-4.stderr
new file mode 100644
index 00000000000..905fa3475ed
--- /dev/null
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-4.stderr
@@ -0,0 +1,31 @@
+warning: the feature `capture_disjoint_fields` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/borrowck-4.rs:1:12
+   |
+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
+
+error[E0373]: closure may outlive the current function, but it borrows `p`, which is owned by the current function
+  --> $DIR/borrowck-4.rs:11:17
+   |
+LL |     let mut c = || {
+   |                 ^^ may outlive borrowed value `p`
+...
+LL |        println!("{:?}", p);
+   |                         - `p` is borrowed here
+   |
+note: closure is returned here
+  --> $DIR/borrowck-4.rs:9:14
+   |
+LL | fn foo () -> impl FnMut()->() {
+   |              ^^^^^^^^^^^^^^^^
+help: to force the closure to take ownership of `p` (and any other referenced variables), use the `move` keyword
+   |
+LL |     let mut c = move || {
+   |                 ^^^^^^^
+
+error: aborting due to previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0373`.
diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-closures-mut-and-imm.rs b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-closures-mut-and-imm.rs
new file mode 100644
index 00000000000..b23947ad5d1
--- /dev/null
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-closures-mut-and-imm.rs
@@ -0,0 +1,26 @@
+// Tests that two closures cannot simultaneously have mutable
+// and immutable access to the variable. Issue #6801.
+
+#![feature(capture_disjoint_fields)]
+//~^ WARNING: the feature `capture_disjoint_fields` is incomplete
+#![feature(box_syntax)]
+
+#[derive(Debug)]
+struct Point {
+    x: i32,
+    y: i32,
+}
+
+fn a() {
+    let mut p = Point {x: 3, y:4};
+    let c2 = || p.y * 5;
+    let c1 = || {
+    //~^ ERROR cannot borrow `p` as mutable because it is also borrowed as immutable
+        dbg!(&p);
+        p.x = 4;
+    };
+    drop(c2);
+}
+
+fn main() {
+}
diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-closures-mut-and-imm.stderr b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-closures-mut-and-imm.stderr
new file mode 100644
index 00000000000..58975c6f46f
--- /dev/null
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/borrowck/borrowck-closures-mut-and-imm.stderr
@@ -0,0 +1,30 @@
+warning: the feature `capture_disjoint_fields` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/borrowck-closures-mut-and-imm.rs:4:12
+   |
+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
+
+error[E0502]: cannot borrow `p` as mutable because it is also borrowed as immutable
+  --> $DIR/borrowck-closures-mut-and-imm.rs:17:14
+   |
+LL |     let c2 = || p.y * 5;
+   |              -- --- first borrow occurs due to use of `p.y` in closure
+   |              |
+   |              immutable borrow occurs here
+LL |     let c1 = || {
+   |              ^^ mutable borrow occurs here
+LL |
+LL |         dbg!(&p);
+   |               - second borrow occurs due to use of `p` in closure
+LL |         p.x = 4;
+   |         --- capture is mutable because of use here
+LL |     };
+LL |     drop(c2);
+   |          -- immutable borrow later used here
+
+error: aborting due to previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0502`.
diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/box.stderr b/src/test/ui/closures/2229_closure_analysis/diagnostics/box.stderr
index 17a9332fb3e..174faa33c49 100644
--- a/src/test/ui/closures/2229_closure_analysis/diagnostics/box.stderr
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/box.stderr
@@ -13,7 +13,7 @@ error[E0506]: cannot assign to `e.0.0.m.x` because it is borrowed
 LL |     let mut c = || {
    |                 -- borrow of `e.0.0.m.x` occurs here
 LL |         e.0.0.m.x = format!("not-x");
-   |         - borrow occurs due to use in closure
+   |         --------- borrow occurs due to use in closure
 ...
 LL |     e.0.0.m.x = format!("not-x");
    |     ^^^^^^^^^ assignment to borrowed `e.0.0.m.x` occurs here
@@ -27,7 +27,7 @@ error[E0502]: cannot borrow `e.0.0.m.x` as immutable because it is also borrowed
 LL |     let mut c = || {
    |                 -- mutable borrow occurs here
 LL |         e.0.0.m.x = format!("not-x");
-   |         - first borrow occurs due to use of `e.0.0.m.x` in closure
+   |         --------- first borrow occurs due to use of `e.0.0.m.x` in closure
 ...
 LL |     println!("{}", e.0.0.m.x);
    |                    ^^^^^^^^^ immutable borrow occurs here
@@ -41,7 +41,7 @@ error[E0506]: cannot assign to `e.0.0.m.x` because it is borrowed
 LL |     let c = || {
    |             -- borrow of `e.0.0.m.x` occurs here
 LL |         println!("{}", e.0.0.m.x);
-   |                        - borrow occurs due to use in closure
+   |                        --------- borrow occurs due to use in closure
 ...
 LL |     e.0.0.m.x = format!("not-x");
    |     ^^^^^^^^^ assignment to borrowed `e.0.0.m.x` occurs here
diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/cant-mutate-imm-borrow.stderr b/src/test/ui/closures/2229_closure_analysis/diagnostics/cant-mutate-imm-borrow.stderr
index 861bc44b78d..39a11fb3327 100644
--- a/src/test/ui/closures/2229_closure_analysis/diagnostics/cant-mutate-imm-borrow.stderr
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/cant-mutate-imm-borrow.stderr
@@ -14,7 +14,7 @@ LL |     let mut c = || {
    |                 ^^ cannot borrow as mutable
 LL |
 LL |         z.0.0.0 = format!("X1");
-   |         - mutable borrow occurs due to use of `z.0.0.0` in closure
+   |         ------- mutable borrow occurs due to use of `z.0.0.0` in closure
 
 error: aborting due to previous error; 1 warning emitted
 
diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/cant-mutate-imm.rs b/src/test/ui/closures/2229_closure_analysis/diagnostics/cant-mutate-imm.rs
index 997ecc7dddd..928c866726f 100644
--- a/src/test/ui/closures/2229_closure_analysis/diagnostics/cant-mutate-imm.rs
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/cant-mutate-imm.rs
@@ -11,7 +11,7 @@ fn mut_error_struct() {
 
     let mut c = || {
         z.0.0.0 = 20;
-        //~^ ERROR: cannot assign to `z`, as it is not declared as mutable
+        //~^ ERROR: cannot assign to `z.0.0.0`, as it is not declared as mutable
     };
 
     c();
@@ -23,7 +23,7 @@ fn mut_error_box() {
 
     let mut c = || {
         bx.0 = 20;
-        //~^ ERROR: cannot assign to `bx`, as it is not declared as mutable
+        //~^ ERROR: cannot assign to `*bx.0`, as it is not declared as mutable
     };
 
     c();
diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/cant-mutate-imm.stderr b/src/test/ui/closures/2229_closure_analysis/diagnostics/cant-mutate-imm.stderr
index 5e15635ac6e..9fb8dd4a1c3 100644
--- a/src/test/ui/closures/2229_closure_analysis/diagnostics/cant-mutate-imm.stderr
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/cant-mutate-imm.stderr
@@ -7,7 +7,7 @@ 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
 
-error[E0594]: cannot assign to `z`, as it is not declared as mutable
+error[E0594]: cannot assign to `z.0.0.0`, as it is not declared as mutable
   --> $DIR/cant-mutate-imm.rs:13:9
    |
 LL |     let z = (y, 10);
@@ -16,7 +16,7 @@ LL |     let z = (y, 10);
 LL |         z.0.0.0 = 20;
    |         ^^^^^^^^^^^^ cannot assign
 
-error[E0594]: cannot assign to `bx`, as it is not declared as mutable
+error[E0594]: cannot assign to `*bx.0`, as it is not declared as mutable
   --> $DIR/cant-mutate-imm.rs:25:9
    |
 LL |     let bx = Box::new(x);
diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/multilevel-path.stderr b/src/test/ui/closures/2229_closure_analysis/diagnostics/multilevel-path.stderr
index e5a396c4e98..a3d1f550557 100644
--- a/src/test/ui/closures/2229_closure_analysis/diagnostics/multilevel-path.stderr
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/multilevel-path.stderr
@@ -13,7 +13,7 @@ error[E0499]: cannot borrow `w.p.x` as mutable more than once at a time
 LL |     let mut c = || {
    |                 -- first mutable borrow occurs here
 LL |         w.p.x += 20;
-   |         - first borrow occurs due to use of `w.p.x` in closure
+   |         ----- first borrow occurs due to use of `w.p.x` in closure
 ...
 LL |     let py = &mut w.p.x;
    |              ^^^^^^^^^^ second mutable borrow occurs here
diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/mut_ref.stderr b/src/test/ui/closures/2229_closure_analysis/diagnostics/mut_ref.stderr
index 8cb2ed2235d..831e486db82 100644
--- a/src/test/ui/closures/2229_closure_analysis/diagnostics/mut_ref.stderr
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/mut_ref.stderr
@@ -17,7 +17,7 @@ LL |     let c = || {
    |             ^^ `ref_mref_x` is a `&` reference, so the data it refers to cannot be borrowed as mutable
 LL |
 LL |         **ref_mref_x = y;
-   |           ---------- mutable borrow occurs due to use of `**ref_mref_x` in closure
+   |         ------------ mutable borrow occurs due to use of `**ref_mref_x` in closure
 
 error[E0596]: cannot borrow `**mref_ref_x` as mutable, as it is behind a `&` reference
   --> $DIR/mut_ref.rs:27:13
@@ -26,7 +26,7 @@ LL |     let c = || {
    |             ^^ cannot borrow as mutable
 LL |
 LL |         **mref_ref_x = y;
-   |           ---------- mutable borrow occurs due to use of `**mref_ref_x` in closure
+   |         ------------ mutable borrow occurs due to use of `**mref_ref_x` in closure
 
 error: aborting due to 2 previous errors; 1 warning emitted
 
diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/simple-struct-min-capture.stderr b/src/test/ui/closures/2229_closure_analysis/diagnostics/simple-struct-min-capture.stderr
index 45a61cd98b1..f1748fda151 100644
--- a/src/test/ui/closures/2229_closure_analysis/diagnostics/simple-struct-min-capture.stderr
+++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/simple-struct-min-capture.stderr
@@ -13,7 +13,9 @@ error[E0502]: cannot borrow `p` as immutable because it is also borrowed as muta
 LL |     let mut c = || {
    |                 -- mutable borrow occurs here
 LL |         p.x += 10;
-   |         - first borrow occurs due to use of `p` in closure
+   |         --- capture is mutable because of use here
+LL |         println!("{:?}", p);
+   |                          - first borrow occurs due to use of `p` in closure
 ...
 LL |     println!("{:?}", p);
    |                      ^ immutable borrow occurs here