Auto merge of #23682 - tamird:DRY-is-empty, r=alexcrichton

r? @alexcrichton

src/test/bench/core-std.rs

@@ -43,7 +43,7 @@ fn maybe_run_test<F>(argv: &[String], name: String, test: F) where F: FnOnce() {
 
     if env::var_os("RUST_BENCH").is_some() {
         run_test = true
-    } else if argv.len() > 0 {
+    } else if !argv.is_empty() {
         run_test = argv.iter().any(|x| x == &"all".to_string()) || argv.iter().any(|x| x == &name)
     }
 
@@ -60,7 +60,7 @@ fn shift_push() {
     let mut v1 = repeat(1).take(30000).collect::<Vec<_>>();
     let mut v2 = Vec::new();
 
-    while v1.len() > 0 {
+    while !v1.is_empty() {
         v2.push(v1.remove(0));
     }
 }

src/test/bench/shootout-k-nucleotide-pipes.rs

@@ -184,7 +184,7 @@ fn main() {
    for line in rdr.lines() {
        let line = line.unwrap().trim().to_string();
 
-       if line.len() == 0 { continue; }
+       if line.is_empty() { continue; }
 
        match (line.as_bytes()[0] as char, proc_mode) {
 

src/test/bench/shootout-k-nucleotide.rs

@@ -252,7 +252,7 @@ fn generate_frequencies(mut input: &[u8], frame: usize) -> Table {
     }
     frequencies.lookup(code, BumpCallback);
 
-    while input.len() != 0 && input[0] != ('>' as u8) {
+    while !input.is_empty() && input[0] != ('>' as u8) {
         code = code.rotate(input[0], frame);
         frequencies.lookup(code, BumpCallback);
         input = &input[1..];

src/test/bench/shootout-nbody.rs

@@ -196,7 +196,7 @@ fn shift_mut_ref<'a, T>(r: &mut &'a mut [T]) -> Option<&'a mut T> {
     use std::mem;
     use std::raw::Repr;
 
-    if r.len() == 0 { return None }
+    if r.is_empty() { return None }
     unsafe {
         let mut raw = r.repr();
         let ret = raw.data as *mut T;

src/test/run-pass/dst-struct-sole.rs

@@ -79,7 +79,7 @@ pub fn main() {
 
     // Zero size vec.
     let f5: &Fat<[isize]> = &Fat { ptr: [] };
-    assert!(f5.ptr.len() == 0);
+    assert!(f5.ptr.is_empty());
     let f5: &Fat<[Bar]> = &Fat { ptr: [] };
-    assert!(f5.ptr.len() == 0);
+    assert!(f5.ptr.is_empty());
 }

src/test/run-pass/dst-struct.rs

@@ -98,9 +98,9 @@ pub fn main() {
 
     // Zero size vec.
     let f5: &Fat<[isize]> = &Fat { f1: 5, f2: "some str", ptr: [] };
-    assert!(f5.ptr.len() == 0);
+    assert!(f5.ptr.is_empty());
     let f5: &Fat<[Bar]> = &Fat { f1: 5, f2: "some str", ptr: [] };
-    assert!(f5.ptr.len() == 0);
+    assert!(f5.ptr.is_empty());
 
     // Deeply nested.
     let f1 = Fat { f1: 5, f2: "some str", ptr: Fat { f1: 8, f2: "deep str", ptr: [1, 2, 3]} };

src/test/run-pass/issue-12860.rs

@@ -30,7 +30,7 @@ fn main() {
     let middle = XYZ{x: 0, y: 0, z: 0};
     border.insert(middle);
 
-    while border.len() > 0 && connected.len() < 10000 {
+    while !border.is_empty() && connected.len() < 10000 {
         let choice = *(border.iter().next().unwrap());
         border.remove(&choice);
         connected.insert(choice);

src/test/run-pass/issue-3556.rs

@@ -44,5 +44,5 @@ pub fn main()
                     "foo".to_string(), "foo".to_string(), "foo".to_string(),
                     "foo".to_string());
     let v = format!("{:?}", u);    // this is the line that causes the seg fault
-    assert!(v.len() > 0);
+    assert!(!v.is_empty());
 }