in which the unused-parens lint comes to cover function and method args

Resolves rust-lang#46137.

Author: zackmdavis

src/liballoc/vec_deque.rs

@@ -2480,7 +2480,7 @@ impl<T> From<VecDeque<T>> for Vec<T> {
             if other.is_contiguous() {
                 ptr::copy(buf.offset(tail as isize), buf, len);
             } else {
-                if (tail - head) >= cmp::min((cap - tail), head) {
+                if (tail - head) >= cmp::min(cap - tail, head) {
                     // There is enough free space in the centre for the shortest block so we can
                     // do this in at most three copy moves.
                     if (cap - tail) > head {

src/librustc_apfloat/ieee.rs

@@ -1434,7 +1434,7 @@ impl<S: Semantics> Float for IeeeFloat<S> {
         let max_change = S::MAX_EXP as i32 - (S::MIN_EXP as i32 - sig_bits) + 1;
 
         // Clamp to one past the range ends to let normalize handle overflow.
-        let exp_change = cmp::min(cmp::max(exp as i32, (-max_change - 1)), max_change);
+        let exp_change = cmp::min(cmp::max(exp as i32, -max_change - 1), max_change);
         self.exp = self.exp.saturating_add(exp_change as ExpInt);
         self = self.normalize(round, Loss::ExactlyZero).value;
         if self.is_nan() {

src/librustc_lint/unused.rs

@@ -302,6 +302,18 @@ impl EarlyLintPass for UnusedParens {
             Assign(_, ref value) => (value, "assigned value", false),
             AssignOp(.., ref value) => (value, "assigned value", false),
             InPlace(_, ref value) => (value, "emplacement value", false),
+            Call(_, ref args) => {
+                for arg in args {
+                    self.check_unused_parens_core(cx, arg, "function argument", false)
+                }
+                return;
+            },
+            MethodCall(_, ref args) => {
+                for arg in &args[1..] { // first "argument" is self (which sometimes needs parens)
+                    self.check_unused_parens_core(cx, arg, "method argument", false)
+                }
+                return;
+            }
             _ => return,
         };
         self.check_unused_parens_core(cx, &value, msg, struct_lit_needs_parens);

src/librustc_mir/dataflow/impls/borrows.rs

@@ -131,7 +131,7 @@ impl<'tcx> fmt::Display for BorrowData<'tcx> {
 }
 
 impl ReserveOrActivateIndex {
-    fn reserved(i: BorrowIndex) -> Self { ReserveOrActivateIndex::new((i.index() * 2)) }
+    fn reserved(i: BorrowIndex) -> Self { ReserveOrActivateIndex::new(i.index() * 2) }
     fn active(i: BorrowIndex) -> Self { ReserveOrActivateIndex::new((i.index() * 2) + 1) }
 
     pub(crate) fn is_reservation(self) -> bool { self.index() % 2 == 0 }

src/librustc_resolve/lib.rs

@@ -963,7 +963,7 @@ impl<'a> ModuleData<'a> {
             unresolved_invocations: RefCell::new(FxHashSet()),
             no_implicit_prelude: false,
             glob_importers: RefCell::new(Vec::new()),
-            globs: RefCell::new((Vec::new())),
+            globs: RefCell::new(Vec::new()),
             traits: RefCell::new(None),
             populated: Cell::new(normal_ancestor_id.is_local()),
             span,

src/libstd/sys/unix/thread.rs

@@ -311,8 +311,8 @@ pub mod guard {
 
     #[cfg(target_os = "macos")]
     pub unsafe fn current() -> Option<usize> {
-        Some((libc::pthread_get_stackaddr_np(libc::pthread_self()) as usize -
-              libc::pthread_get_stacksize_np(libc::pthread_self())))
+        Some(libc::pthread_get_stackaddr_np(libc::pthread_self()) as usize -
+             libc::pthread_get_stacksize_np(libc::pthread_self()))
     }
 
     #[cfg(any(target_os = "openbsd", target_os = "bitrig"))]

src/test/compile-fail/lint-unnecessary-parens.rs

@@ -13,19 +13,19 @@
 #[derive(Eq, PartialEq)]
 struct X { y: bool }
 impl X {
-    fn foo(&self) -> bool { self.y }
+    fn foo(&self, conjunct: bool) -> bool { self.y && conjunct }
 }
 
 fn foo() -> isize {
     return (1); //~ ERROR unnecessary parentheses around `return` value
 }
-fn bar() -> X {
-    return (X { y: true }); //~ ERROR unnecessary parentheses around `return` value
+fn bar(y: bool) -> X {
+    return (X { y }); //~ ERROR unnecessary parentheses around `return` value
 }
 
 fn main() {
     foo();
-    bar();
+    bar((true)); //~ ERROR unnecessary parentheses around function argument
 
     if (true) {} //~ ERROR unnecessary parentheses around `if` condition
     while (true) {} //~ ERROR unnecessary parentheses around `while` condition
@@ -40,13 +40,15 @@ fn main() {
     if (X { y: true } == v) {}
     if (X { y: false }.y) {}
 
-    while (X { y: false }.foo()) {}
+    while (X { y: false }.foo(true)) {}
     while (true | X { y: false }.y) {}
 
     match (X { y: false }) {
         _ => {}
     }
 
+    X { y: false }.foo((true)); //~ ERROR unnecessary parentheses around method argument
+
     let mut _a = (0); //~ ERROR unnecessary parentheses around assigned value
     _a = (0); //~ ERROR unnecessary parentheses around assigned value
     _a += (1); //~ ERROR unnecessary parentheses around assigned value