librustc: Allow &mut to be loaned; allow self to be loaned; make &mut loanable to &. r=nmatsakis

src/test/compile-fail/borrowck-autoref-3261.rs

@@ -20,7 +20,7 @@ fn main() {
     do (&mut x).with |opt| {  //~ ERROR illegal borrow
         match opt {
             &Right(ref f) => {
-                x = X(Left((0,0)));
+                x = X(Left((0,0))); //~ ERROR assigning to captured outer mutable variable
                 (*f)()
             },
             _ => fail

src/test/compile-fail/borrowck-call-method-from-mut-aliasable.rs

@@ -19,7 +19,7 @@ impl Foo {
 }
 
 fn a(x: &mut Foo) {
-    x.f(); //~ ERROR illegal borrow unless pure
+    x.f();
     x.g();
     x.h();
 }

src/test/compile-fail/borrowck-imm-field-mut-base.rs

@@ -22,8 +22,9 @@ fn main() {
     let q = &mut b.foo; //~ ERROR loan of mutable field as mutable conflicts with prior loan
     //~^ ERROR loan of mutable local variable as mutable conflicts with prior loan
     let r = &mut b; //~ ERROR loan of mutable local variable as mutable conflicts with prior loan
+    //~^ ERROR loan of mutable local variable as mutable conflicts with prior loan
     io::println(fmt!("*p = %u", *p));
     q.x += 1;
     r.foo.x += 1;
     io::println(fmt!("*p = %u", *p));
-}
+}

src/test/compile-fail/borrowck-imm-ref-to-mut-rec-field-issue-3162-c.rs

@@ -10,9 +10,9 @@
 
 fn main() {
     let mut _a = 3;
-    let _b = &mut _a;
+    let _b = &mut _a; //~ NOTE loan of mutable local variable granted here
     {
-        let _c = &*_b; //~ ERROR illegal borrow unless pure
-        _a = 4; //~ NOTE impure due to assigning to mutable local variable
+        let _c = &*_b;
+        _a = 4; //~ ERROR assigning to mutable local variable prohibited
     }
 }

src/test/compile-fail/borrowck-uniq-via-ref.rs

@@ -11,7 +11,7 @@
 fn borrow(_v: &int) {}
 
 fn box_mut(v: &mut ~int) {
-    borrow(*v); //~ ERROR illegal borrow unless pure
+    borrow(*v); // OK: &mut -> &imm
 }
 
 fn box_rec_mut(v: &{mut f: ~int}) {
@@ -19,11 +19,11 @@ fn box_rec_mut(v: &{mut f: ~int}) {
 }
 
 fn box_mut_rec(v: &mut {f: ~int}) {
-    borrow(v.f); //~ ERROR illegal borrow unless pure
+    borrow(v.f); // OK: &mut -> &imm
 }
 
 fn box_mut_recs(v: &mut {f: {g: {h: ~int}}}) {
-    borrow(v.f.g.h); //~ ERROR illegal borrow unless pure
+    borrow(v.f.g.h); // OK: &mut -> &imm
 }
 
 fn box_imm(v: &~int) {

src/test/compile-fail/borrowck-wg-borrow-mut-to-imm-fail-2.rs

@@ -0,0 +1,6 @@
+fn main() {
+    let mut b = ~3;
+    let _x = &mut *b;   //~ NOTE prior loan as mutable granted here
+    let _y = &mut *b;   //~ ERROR loan of dereference of mutable ~ pointer as mutable conflicts with prior loan
+}
+

src/test/compile-fail/borrowck-wg-borrow-mut-to-imm-fail-3.rs

@@ -0,0 +1,8 @@
+fn main() {
+    let mut a = ~3;
+    let mut b = &mut a; //~ NOTE loan of mutable local variable granted here
+    let _c = &mut *b;
+    let mut d = /*move*/ a; //~ ERROR moving out of mutable local variable prohibited due to outstanding loan
+    *d += 1;
+}
+

src/test/compile-fail/borrowck-wg-borrow-mut-to-imm-fail.rs

@@ -0,0 +1,7 @@
+fn main() {
+    let mut b = ~3;
+    let _x = &mut *b;   //~ NOTE loan of mutable local variable granted here
+    let mut y = /*move*/ b; //~ ERROR moving out of mutable local variable prohibited
+    *y += 1;
+}
+

src/test/compile-fail/borrowck-wg-move-base-2.rs

@@ -0,0 +1,11 @@
+fn foo(x: &mut int) {
+    let mut a = 3;
+    let mut _y = &mut *x;
+    let _z = &mut *_y;
+    _y = &mut a; //~ ERROR assigning to mutable local variable prohibited
+}
+
+fn main() {
+}
+
+

src/test/compile-fail/regions-escape-loop-via-vec.rs

@@ -15,7 +15,7 @@ fn broken() {
     while x < 10 {
         let mut z = x;
         _y.push(&mut z); //~ ERROR illegal borrow
-        x += 1;
+        x += 1; //~ ERROR assigning to mutable local variable prohibited due to outstanding loan
     }
 }
 

src/test/run-pass/borrowck-binding-mutbl.rs

@@ -16,8 +16,7 @@ fn main() {
 
     match x {
       {f: ref mut v} => {
-        impure(*v); //~ ERROR illegal borrow unless pure
-        //~^ NOTE impure due to access to impure function
+        impure(*v);
       }
     }
 }

src/test/run-pass/borrowck-lend-args.rs

@@ -15,8 +15,7 @@ fn borrow_from_arg_imm_ref(&&v: ~int) {
 }
 
 fn borrow_from_arg_mut_ref(v: &mut ~int) {
-    borrow(*v); //~ ERROR illegal borrow unless pure
-    //~^ NOTE impure due to access to impure function
+    borrow(*v);
 }
 
 fn borrow_from_arg_move(-v: ~int) {

src/test/run-pass/borrowck-wg-borrow-mut-to-imm-2.rs

@@ -0,0 +1,13 @@
+struct Cat;
+
+fn bar(_: &Cat) {
+}
+
+fn foo(cat: &mut Cat) {
+    bar(&*cat);
+}
+
+fn main() {
+    let mut mimi = ~Cat;
+    foo(mimi);
+}

src/test/run-pass/borrowck-wg-borrow-mut-to-imm-3.rs

@@ -0,0 +1,18 @@
+struct Wizard {
+    spells: ~[&static/str]
+}
+
+impl Wizard {
+    fn cast(&mut self) {
+        for self.spells.each |&spell| {
+            io::println(spell);
+        }
+    }
+}
+
+fn main() {
+    let mut harry = Wizard {
+        spells: ~[ "expelliarmus", "expecto patronum", "incendio" ]
+    };
+    harry.cast();
+}

src/test/run-pass/borrowck-wg-borrow-mut-to-imm.rs

@@ -0,0 +1,12 @@
+fn g(x: &Option<int>) {
+    io::println(x.get().to_str());
+}
+
+fn f(x: &mut Option<int>) {
+    g(&*x);
+}
+
+fn main() {
+    let mut x = ~Some(3);
+    f(x);
+}