only call next() once per iteration in Enumerate. fixes #6284

this definition is now inlined too.

base/iterator.jl

@@ -10,7 +10,8 @@ enumerate(itr) = Enumerate(itr)
 length(e::Enumerate) = length(e.itr)
 start(e::Enumerate) = (1, start(e.itr))
 function next(e::Enumerate, state)
-    (state[1],next(e.itr,state[2])[1]), (state[1]+1,next(e.itr,state[2])[2])
+    n = next(e.itr,state[2])
+    (state[1],n[1]), (state[1]+1,n[2])
 end
 done(e::Enumerate, state) = done(e.itr, state[2])
 

test/functional.jl

@@ -47,3 +47,11 @@ end
 # zip and filter iterators
 # issue #4718
 @test collect(filter(x->x[1], zip([true, false, true, false],"abcd"))) == {(true,'a'),(true,'c')}
+
+# enumerate (issue #6284)
+let b = IOBuffer("1\n2\n3\n"), a = {}
+    for (i,x) in enumerate(eachline(b))
+        push!(a, (i,x))
+    end
+    @test a == {(1,"1\n"),(2,"2\n"),(3,"3\n")}
+end