Negative case of len() -> is_empty()

`s/([^\(\s]+\.)len\(\) [(?:!=)>] 0/!$1is_empty()/g`

Author: tamird

src/compiletest/compiletest.rs

@@ -368,7 +368,7 @@ pub fn make_metrics_test_closure(config: &Config, testfile: &Path) -> test::Test
 fn extract_gdb_version(full_version_line: Option<String>) -> Option<String> {
     match full_version_line {
         Some(ref full_version_line)
-          if full_version_line.trim().len() > 0 => {
+          if !full_version_line.trim().is_empty() => {
             let full_version_line = full_version_line.trim();
 
             // used to be a regex "(^|[^0-9])([0-9]\.[0-9])([^0-9]|$)"
@@ -408,7 +408,7 @@ fn extract_lldb_version(full_version_line: Option<String>) -> Option<String> {
 
     match full_version_line {
         Some(ref full_version_line)
-          if full_version_line.trim().len() > 0 => {
+          if !full_version_line.trim().is_empty() => {
             let full_version_line = full_version_line.trim();
 
             for (pos, l) in full_version_line.char_indices() {
@@ -426,7 +426,7 @@ fn extract_lldb_version(full_version_line: Option<String>) -> Option<String> {
                 let vers = full_version_line[pos + 5..].chars().take_while(|c| {
                     c.is_digit(10)
                 }).collect::<String>();
-                if vers.len() > 0 { return Some(vers) }
+                if !vers.is_empty() { return Some(vers) }
             }
             println!("Could not extract LLDB version from line '{}'",
                      full_version_line);

src/libcollections/btree/node.rs

@@ -1225,7 +1225,7 @@ impl<K, V> Node<K, V> {
     /// because we have one too many, and our parent now has one too few
     fn split(&mut self) -> (K, V, Node<K, V>) {
         // Necessary for correctness, but in a private function
-        debug_assert!(self.len() > 0);
+        debug_assert!(!self.is_empty());
 
         let mut right = if self.is_leaf() {
             Node::new_leaf(self.capacity())

src/libcore/char.rs

@@ -227,7 +227,7 @@ impl CharExt for char {
 #[inline]
 pub fn encode_utf8_raw(code: u32, dst: &mut [u8]) -> Option<usize> {
     // Marked #[inline] to allow llvm optimizing it away
-    if code < MAX_ONE_B && dst.len() >= 1 {
+    if code < MAX_ONE_B && !dst.is_empty() {
         dst[0] = code as u8;
         Some(1)
     } else if code < MAX_TWO_B && dst.len() >= 2 {
@@ -258,7 +258,7 @@ pub fn encode_utf8_raw(code: u32, dst: &mut [u8]) -> Option<usize> {
 #[inline]
 pub fn encode_utf16_raw(mut ch: u32, dst: &mut [u16]) -> Option<usize> {
     // Marked #[inline] to allow llvm optimizing it away
-    if (ch & 0xFFFF) == ch  && dst.len() >= 1 {
+    if (ch & 0xFFFF) == ch && !dst.is_empty() {
         // The BMP falls through (assuming non-surrogate, as it should)
         dst[0] = ch as u16;
         Some(1)

src/libfmt_macros/lib.rs

@@ -371,7 +371,7 @@ impl<'a> Parser<'a> {
             None => {
                 let tmp = self.cur.clone();
                 match self.word() {
-                    word if word.len() > 0 => {
+                    word if !word.is_empty() => {
                         if self.consume('$') {
                             CountIsName(word)
                         } else {
@@ -463,7 +463,7 @@ mod tests {
     fn musterr(s: &str) {
         let mut p = Parser::new(s);
         p.next();
-        assert!(p.errors.len() != 0);
+        assert!(!p.errors.is_empty());
     }
 
     #[test]

src/libgetopts/lib.rs

@@ -804,7 +804,7 @@ fn format_option(opt: &OptGroup) -> String {
     }
 
     // Use short_name is possible, but fallback to long_name.
-    if opt.short_name.len() > 0 {
+    if !opt.short_name.is_empty() {
         line.push('-');
         line.push_str(&opt.short_name[..]);
     } else {

src/librustc/metadata/encoder.rs

@@ -469,7 +469,7 @@ fn each_auxiliary_node_id<F>(item: &ast::Item, callback: F) -> bool where
         ast::ItemStruct(ref struct_def, _) => {
             // If this is a newtype struct, return the constructor.
             match struct_def.ctor_id {
-                Some(ctor_id) if struct_def.fields.len() > 0 &&
+                Some(ctor_id) if !struct_def.fields.is_empty() &&
                         struct_def.fields[0].node.kind.is_unnamed() => {
                     continue_ = callback(ctor_id);
                 }

src/librustc/metadata/loader.rs

@@ -307,13 +307,13 @@ impl<'a> Context<'a> {
     }
 
     pub fn report_load_errs(&mut self) {
-        let message = if self.rejected_via_hash.len() > 0 {
+        let message = if !self.rejected_via_hash.is_empty() {
             format!("found possibly newer version of crate `{}`",
                     self.ident)
-        } else if self.rejected_via_triple.len() > 0 {
+        } else if !self.rejected_via_triple.is_empty() {
             format!("couldn't find crate `{}` with expected target triple {}",
                     self.ident, self.triple)
-        } else if self.rejected_via_kind.len() > 0 {
+        } else if !self.rejected_via_kind.is_empty() {
             format!("found staticlib `{}` instead of rlib or dylib", self.ident)
         } else {
             format!("can't find crate for `{}`", self.ident)
@@ -325,15 +325,15 @@ impl<'a> Context<'a> {
         };
         self.sess.span_err(self.span, &message[..]);
 
-        if self.rejected_via_triple.len() > 0 {
+        if !self.rejected_via_triple.is_empty() {
             let mismatches = self.rejected_via_triple.iter();
             for (i, &CrateMismatch{ ref path, ref got }) in mismatches.enumerate() {
                 self.sess.fileline_note(self.span,
                     &format!("crate `{}`, path #{}, triple {}: {}",
                             self.ident, i+1, got, path.display()));
             }
         }
-        if self.rejected_via_hash.len() > 0 {
+        if !self.rejected_via_hash.is_empty() {
             self.sess.span_note(self.span, "perhaps this crate needs \
                                             to be recompiled?");
             let mismatches = self.rejected_via_hash.iter();
@@ -353,7 +353,7 @@ impl<'a> Context<'a> {
                 }
             }
         }
-        if self.rejected_via_kind.len() > 0 {
+        if !self.rejected_via_kind.is_empty() {
             self.sess.fileline_help(self.span, "please recompile this crate using \
                                             --crate-type lib");
             let mismatches = self.rejected_via_kind.iter();

src/librustc/middle/dead.rs

@@ -182,7 +182,7 @@ impl<'a, 'tcx> MarkSymbolVisitor<'a, 'tcx> {
 
     fn mark_live_symbols(&mut self) {
         let mut scanned = HashSet::new();
-        while self.worklist.len() > 0 {
+        while !self.worklist.is_empty() {
             let id = self.worklist.pop().unwrap();
             if scanned.contains(&id) {
                 continue

src/librustc/middle/infer/error_reporting.rs

@@ -966,7 +966,7 @@ impl<'a, 'tcx> Rebuilder<'a, 'tcx> {
     fn pick_lifetime(&self,
                      region_names: &HashSet<ast::Name>)
                      -> (ast::Lifetime, FreshOrKept) {
-        if region_names.len() > 0 {
+        if !region_names.is_empty() {
             // It's not necessary to convert the set of region names to a
             // vector of string and then sort them. However, it makes the
             // choice of lifetime name deterministic and thus easier to test.

src/librustc/middle/infer/region_inference/mod.rs

@@ -246,7 +246,7 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
     }
 
     fn in_snapshot(&self) -> bool {
-        self.undo_log.borrow().len() > 0
+        !self.undo_log.borrow().is_empty()
     }
 
     pub fn start_snapshot(&self) -> RegionSnapshot {