diff --git a/cc/image.bzl b/cc/image.bzl
index 90a3f5617..2cf7347e1 100644
--- a/cc/image.bzl
+++ b/cc/image.bzl
@@ -76,13 +76,11 @@ def cc_image(name, base=None, deps=[], layers=[], binary=None, **kwargs):
   elif deps:
     fail("kwarg does nothing when binary is specified", "deps")
 
-  index = 0
   base = base or DEFAULT_BASE
-  for dep in layers:
+  for index, dep in enumerate(layers):
     this_name = "%s.%d" % (name, index)
     dep_layer(name=this_name, base=base, dep=dep)
     base = this_name
-    index += 1
 
   visibility = kwargs.get('visibility', None)
   app_layer(name=name, base=base, binary=binary, layers=layers,
diff --git a/contrib/push-all.bzl b/contrib/push-all.bzl
index d1a81ba09..21f334049 100644
--- a/contrib/push-all.bzl
+++ b/contrib/push-all.bzl
@@ -38,8 +38,7 @@ def _impl(ctx):
 
   scripts = []
   runfiles = []
-  index = 0
-  for tag in images:
+  for index, tag in enumerate(images.keys()):
     image = images[tag]
     # Leverage our efficient intermediate representation to push.
     legacy_base_arg = ""
@@ -77,7 +76,6 @@ def _impl(ctx):
 
     scripts += [out]
     runfiles += [out]
-    index += 1
 
   ctx.template_action(
     template = ctx.file._all_tpl,
diff --git a/d/image.bzl b/d/image.bzl
index 44a3fd3a0..8a518566c 100644
--- a/d/image.bzl
+++ b/d/image.bzl
@@ -49,13 +49,11 @@ def d_image(name, base=None, deps=[], layers=[], binary=None, **kwargs):
   elif deps:
     fail("kwarg does nothing when binary is specified", "deps")
 
-  index = 0
   base = base or DEFAULT_BASE
-  for dep in layers:
+  for index, dep in enumerate(layers):
     this_name = "%s_%d" % (name, index)
     dep_layer(name=this_name, base=base, dep=dep)
     base = this_name
-    index += 1
 
   visibility = kwargs.get('visibility', None)
   app_layer(name=name, base=base, binary=binary, layers=layers,
diff --git a/go/image.bzl b/go/image.bzl
index a85e61f2d..f8320b4a9 100644
--- a/go/image.bzl
+++ b/go/image.bzl
@@ -80,13 +80,11 @@ def go_image(name, base=None, deps=[], layers=[], binary=None, **kwargs):
   elif deps:
     fail("kwarg does nothing when binary is specified", "deps")
 
-  index = 0
   base = base or DEFAULT_BASE
-  for dep in layers:
+  for index, dep in enumerate(layers):
     this_name = "%s.%d" % (name, index)
     dep_layer(name=this_name, base=base, dep=dep)
     base = this_name
-    index += 1
 
   visibility = kwargs.get('visibility', None)
   app_layer(name=name, base=base, binary=binary, layers=layers,
diff --git a/java/image.bzl b/java/image.bzl
index 4ce121def..a64419a8c 100644
--- a/java/image.bzl
+++ b/java/image.bzl
@@ -238,13 +238,11 @@ def java_image(name, base=None, main_class=None,
                      deps=(deps + layers) or None, runtime_deps=runtime_deps,
                      jvm_flags=jvm_flags, **kwargs)
 
-  index = 0
   base = base or DEFAULT_JAVA_BASE
-  for dep in layers:
+  for index, dep in enumerate(layers):
     this_name = "%s.%d" % (name, index)
     jar_dep_layer(name=this_name, base=base, dep=dep)
     base = this_name
-    index += 1
 
   visibility = kwargs.get('visibility', None)
   jar_app_layer(name=name, base=base, binary=binary_name,
@@ -353,13 +351,11 @@ def war_image(name, base=None, deps=[], layers=[], **kwargs):
 
   native.java_library(name=library_name, deps=deps + layers, **kwargs)
 
-  index = 0
   base = base or DEFAULT_JETTY_BASE
-  for dep in layers:
+  for index, dep in enumerate(layers):
     this_name = "%s.%d" % (name, index)
     _war_dep_layer(name=this_name, base=base, dep=dep)
     base = this_name
-    index += 1
 
   visibility = kwargs.get('visibility', None)
   _war_app_layer(name=name, base=base, library=library_name, layers=layers,
diff --git a/nodejs/image.bzl b/nodejs/image.bzl
index 581471281..617018599 100644
--- a/nodejs/image.bzl
+++ b/nodejs/image.bzl
@@ -122,13 +122,11 @@ def nodejs_image(name, base=None, data=[], layers=[],
 
   # TODO(mattmoor): Consider making the directory into which the app
   # is placed configurable.
-  index = 0
   base = base or DEFAULT_BASE
-  for dep in layers:
+  for index, dep in enumerate(layers):
     this_name = "%s.%d" % (name, index)
     _dep_layer(name=this_name, base=base, dep=dep, binary=binary_name)
     base = this_name
-    index += 1
 
   visibility = kwargs.get('visibility', None)
   app_layer(name=name, base=base, entrypoint=['sh', '-c'],
diff --git a/python/image.bzl b/python/image.bzl
index 24e5ec546..2adbd70e0 100644
--- a/python/image.bzl
+++ b/python/image.bzl
@@ -74,13 +74,11 @@ def py_image(name, base=None, deps=[], layers=[], **kwargs):
 
   # TODO(mattmoor): Consider making the directory into which the app
   # is placed configurable.
-  index = 0
   base = base or DEFAULT_BASE
-  for dep in layers:
+  for index, dep in enumerate(layers):
     this_name = "%s.%d" % (name, index)
     dep_layer(name=this_name, base=base, dep=dep)
     base = this_name
-    index += 1
 
   visibility = kwargs.get('visibility', None)
   app_layer(name=name, base=base, entrypoint=['/usr/bin/python'],
diff --git a/python3/image.bzl b/python3/image.bzl
index 5f1703442..5b844b0f1 100644
--- a/python3/image.bzl
+++ b/python3/image.bzl
@@ -74,13 +74,11 @@ def py3_image(name, base=None, deps=[], layers=[], **kwargs):
 
   # TODO(mattmoor): Consider making the directory into which the app
   # is placed configurable.
-  index = 0
   base = base or DEFAULT_BASE
-  for dep in layers:
+  for index, dep in enumerate(layers):
     this_name = "%s.%d" % (name, index)
     dep_layer(name=this_name, base=base, dep=dep)
     base = this_name
-    index += 1
 
   visibility = kwargs.get('visibility', None)
   app_layer(name=name, base=base, entrypoint=['/usr/bin/python'],
diff --git a/rust/image.bzl b/rust/image.bzl
index 52a490573..46ce10be6 100644
--- a/rust/image.bzl
+++ b/rust/image.bzl
@@ -49,13 +49,11 @@ def rust_image(name, base=None, deps=[], layers=[], binary=None, **kwargs):
   elif deps:
     fail("kwarg does nothing when binary is specified", "deps")
 
-  index = 0
   base = base or DEFAULT_BASE
-  for dep in layers:
+  for index, dep in enumerate(layers):
     this_name = "%s_%d" % (name, index)
     dep_layer(name=this_name, base=base, dep=dep)
     base = this_name
-    index += 1
 
   visibility = kwargs.get('visibility', None)
   app_layer(name=name, base=base, binary=binary, layers=layers,
diff --git a/scala/image.bzl b/scala/image.bzl
index a6a151fc2..380b81b69 100644
--- a/scala/image.bzl
+++ b/scala/image.bzl
@@ -47,13 +47,11 @@ def scala_image(name, base=None, main_class=None,
                       deps=(deps + layers) or None, runtime_deps=runtime_deps,
                       jvm_flags=jvm_flags, **kwargs)
 
-  index = 0
   base = base or DEFAULT_JAVA_BASE
-  for dep in layers:
+  for index, dep in enumerate(layers):
     this_name = "%s.%d" % (name, index)
     jar_dep_layer(name=this_name, base=base, dep=dep)
     base = this_name
-    index += 1
 
   visibility = kwargs.get('visibility', None)
   jar_app_layer(name=name, base=base, binary=binary_name,