This commit is about not calling .length or .si...

This commit is about not calling .length or .size on Lists. Sometimes it
is unavoidable; not often. I created some methods for the compiler which
should probably be in the collections, which do things like test if two
sequences have the same length in a more efficient manner than calling
length on each.

Also, wouldn't it be wonderful to have some mechanism for finding these
issues in a more automated way. Like say an annotation:

  LinearSeqLike {
    @badjuju("Calling length on linear seqs is O(n)")
    def length: Int = whee
  }

Or since I imagine everyone thinks they're calling length with lists of
2 or 3, an optional runtime check which yelled if it sees you calling
length on a 600 element list, or worse:

  var i = 0
  while (i < myList.length) { // you don't want to see what this does
    f(myList(i)) ; i += 1;
  }

Uniformity of interface without uniformity of behavior leaves us with
traps. No review.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/compiler/scala/tools/nsc/backend/icode/Linearizers.scala b/src/compiler/scala/tools/nsc/backend/icode/Linearizers.scala
index aaf8037768..2151fdaaf2 100644
--- a/src/compiler/scala/tools/nsc/backend/icode/Linearizers.scala
+++ b/src/compiler/scala/tools/nsc/backend/icode/Linearizers.scala
@@ -60,7 +60,7 @@ trait Linearizers { self: ICodes =>
     }
 
     def processElement(b: BasicBlock) =
-      if (b.size > 0) {
+      if (b.nonEmpty) {
         add(b);
         b.lastInstruction match {
           case JUMP(whereto) =>
@@ -118,7 +118,7 @@ trait Linearizers { self: ICodes =>
     }
 
     def dfs(b: BasicBlock): Unit =
-      if (b.size > 0 && add(b))
+      if (b.nonEmpty && add(b))
         b.successors foreach dfs;
 
     /**