diff --git a/src/core/channel/client_channel.c b/src/core/channel/client_channel.c
index 2e25033..7f6b71e 100644
--- a/src/core/channel/client_channel.c
+++ b/src/core/channel/client_channel.c
@@ -380,18 +380,18 @@
           gpr_mu_lock(&chand->mu_config);
           lb_policy = chand->lb_policy;
           if (lb_policy) {
-            grpc_transport_stream_op *op = &calld->waiting_op;
-            grpc_pollset *bind_pollset = op->bind_pollset;
+            grpc_transport_stream_op *waiting_op = &calld->waiting_op;
+            grpc_pollset *bind_pollset = waiting_op->bind_pollset;
             grpc_metadata_batch *initial_metadata =
-                &op->send_ops->ops[0].data.metadata;
+                &waiting_op->send_ops->ops[0].data.metadata;
             GRPC_LB_POLICY_REF(lb_policy, "pick");
             gpr_mu_unlock(&chand->mu_config);
             calld->state = CALL_WAITING_FOR_PICK;
 
-            GPR_ASSERT(op->bind_pollset);
-            GPR_ASSERT(op->send_ops);
-            GPR_ASSERT(op->send_ops->nops >= 1);
-            GPR_ASSERT(op->send_ops->ops[0].type == GRPC_OP_METADATA);
+            GPR_ASSERT(waiting_op->bind_pollset);
+            GPR_ASSERT(waiting_op->send_ops);
+            GPR_ASSERT(waiting_op->send_ops->nops >= 1);
+            GPR_ASSERT(waiting_op->send_ops->ops[0].type == GRPC_OP_METADATA);
             gpr_mu_unlock(&calld->mu_state);
 
             grpc_iomgr_closure_init(&calld->async_setup_task, picked_target,
diff --git a/src/core/channel/http_client_filter.c b/src/core/channel/http_client_filter.c
index ec832a0..136292b 100644
--- a/src/core/channel/http_client_filter.c
+++ b/src/core/channel/http_client_filter.c
@@ -119,21 +119,21 @@
     size_t nops = op->send_ops->nops;
     grpc_stream_op *ops = op->send_ops->ops;
     for (i = 0; i < nops; i++) {
-      grpc_stream_op *op = &ops[i];
-      if (op->type != GRPC_OP_METADATA) continue;
+      grpc_stream_op *stream_op = &ops[i];
+      if (stream_op->type != GRPC_OP_METADATA) continue;
       calld->sent_initial_metadata = 1;
-      grpc_metadata_batch_filter(&op->data.metadata, client_strip_filter, elem);
+      grpc_metadata_batch_filter(&stream_op->data.metadata, client_strip_filter, elem);
       /* Send : prefixed headers, which have to be before any application
          layer headers. */
-      grpc_metadata_batch_add_head(&op->data.metadata, &calld->method,
+      grpc_metadata_batch_add_head(&stream_op->data.metadata, &calld->method,
                                    GRPC_MDELEM_REF(channeld->method));
-      grpc_metadata_batch_add_head(&op->data.metadata, &calld->scheme,
+      grpc_metadata_batch_add_head(&stream_op->data.metadata, &calld->scheme,
                                    GRPC_MDELEM_REF(channeld->scheme));
-      grpc_metadata_batch_add_tail(&op->data.metadata, &calld->te_trailers,
+      grpc_metadata_batch_add_tail(&stream_op->data.metadata, &calld->te_trailers,
                                    GRPC_MDELEM_REF(channeld->te_trailers));
-      grpc_metadata_batch_add_tail(&op->data.metadata, &calld->content_type,
+      grpc_metadata_batch_add_tail(&stream_op->data.metadata, &calld->content_type,
                                    GRPC_MDELEM_REF(channeld->content_type));
-      grpc_metadata_batch_add_tail(&op->data.metadata, &calld->user_agent,
+      grpc_metadata_batch_add_tail(&stream_op->data.metadata, &calld->user_agent,
                                    GRPC_MDELEM_REF(channeld->user_agent));
       break;
     }
diff --git a/src/core/channel/http_server_filter.c b/src/core/channel/http_server_filter.c
index 0955ae3..0ed9fa9 100644
--- a/src/core/channel/http_server_filter.c
+++ b/src/core/channel/http_server_filter.c
@@ -197,10 +197,10 @@
     size_t nops = op->send_ops->nops;
     grpc_stream_op *ops = op->send_ops->ops;
     for (i = 0; i < nops; i++) {
-      grpc_stream_op *op = &ops[i];
-      if (op->type != GRPC_OP_METADATA) continue;
+      grpc_stream_op *stream_op = &ops[i];
+      if (stream_op->type != GRPC_OP_METADATA) continue;
       calld->sent_status = 1;
-      grpc_metadata_batch_add_head(&op->data.metadata, &calld->status,
+      grpc_metadata_batch_add_head(&stream_op->data.metadata, &calld->status,
                                    GRPC_MDELEM_REF(channeld->status_ok));
       break;
     }
diff --git a/src/core/iomgr/resolve_address_posix.c b/src/core/iomgr/resolve_address_posix.c
index ce6972b..91754eb 100644
--- a/src/core/iomgr/resolve_address_posix.c
+++ b/src/core/iomgr/resolve_address_posix.c
@@ -50,6 +50,7 @@
 #include <grpc/support/string_util.h>
 #include <grpc/support/thd.h>
 #include <grpc/support/time.h>
+#include <grpc/support/useful.h>
 
 typedef struct {
   char *name;
@@ -106,8 +107,7 @@
   if (s != 0) {
     /* Retry if well-known service name is recognized */
     char *svc[][2] = {{"http", "80"}, {"https", "443"}};
-    int i;
-    for (i = 0; i < (int)(sizeof(svc) / sizeof(svc[0])); i++) {
+    for (i = 0; i < GPR_ARRAY_SIZE(svc); i++) {
       if (strcmp(port, svc[i][0]) == 0) {
         s = getaddrinfo(host, svc[i][1], &hints, &result);
         break;
diff --git a/src/core/security/credentials.c b/src/core/security/credentials.c
index a764413..87669b9 100644
--- a/src/core/security/credentials.c
+++ b/src/core/security/credentials.c
@@ -223,7 +223,7 @@
   grpc_security_status status = GRPC_SECURITY_OK;
   size_t i = 0;
   const char *overridden_target_name = NULL;
-  grpc_arg arg;
+  grpc_arg new_arg;
 
   for (i = 0; args && i < args->num_args; i++) {
     grpc_arg *arg = &args->args[i];
@@ -238,10 +238,10 @@
   if (status != GRPC_SECURITY_OK) {
     return status;
   }
-  arg.type = GRPC_ARG_STRING;
-  arg.key = GRPC_ARG_HTTP2_SCHEME;
-  arg.value.string = "https";
-  *new_args = grpc_channel_args_copy_and_add(args, &arg, 1);
+  new_arg.type = GRPC_ARG_STRING;
+  new_arg.key = GRPC_ARG_HTTP2_SCHEME;
+  new_arg.value.string = "https";
+  *new_args = grpc_channel_args_copy_and_add(args, &new_arg, 1);
   return status;
 }
 
diff --git a/src/core/support/cmdline.c b/src/core/support/cmdline.c
index 45a3182..87f60bc 100644
--- a/src/core/support/cmdline.c
+++ b/src/core/support/cmdline.c
@@ -192,9 +192,9 @@
   exit(1);
 }
 
-static void extra_state(gpr_cmdline *cl, char *arg) {
+static void extra_state(gpr_cmdline *cl, char *str) {
   if (!cl->extra_arg) print_usage_and_die(cl);
-  cl->extra_arg(cl->extra_arg_user_data, arg);
+  cl->extra_arg(cl->extra_arg_user_data, str);
 }
 
 static arg *find_arg(gpr_cmdline *cl, char *name) {
@@ -214,7 +214,7 @@
   return a;
 }
 
-static void value_state(gpr_cmdline *cl, char *arg) {
+static void value_state(gpr_cmdline *cl, char *str) {
   long intval;
   char *end;
 
@@ -222,80 +222,80 @@
 
   switch (cl->cur_arg->type) {
     case ARGTYPE_INT:
-      intval = strtol(arg, &end, 0);
+      intval = strtol(str, &end, 0);
       if (*end || intval < INT_MIN || intval > INT_MAX) {
-        fprintf(stderr, "expected integer, got '%s' for %s\n", arg,
+        fprintf(stderr, "expected integer, got '%s' for %s\n", str,
                 cl->cur_arg->name);
         print_usage_and_die(cl);
       }
       *(int *)cl->cur_arg->value = (int)intval;
       break;
     case ARGTYPE_BOOL:
-      if (0 == strcmp(arg, "1") || 0 == strcmp(arg, "true")) {
+      if (0 == strcmp(str, "1") || 0 == strcmp(str, "true")) {
         *(int *)cl->cur_arg->value = 1;
-      } else if (0 == strcmp(arg, "0") || 0 == strcmp(arg, "false")) {
+      } else if (0 == strcmp(str, "0") || 0 == strcmp(str, "false")) {
         *(int *)cl->cur_arg->value = 0;
       } else {
-        fprintf(stderr, "expected boolean, got '%s' for %s\n", arg,
+        fprintf(stderr, "expected boolean, got '%s' for %s\n", str,
                 cl->cur_arg->name);
         print_usage_and_die(cl);
       }
       break;
     case ARGTYPE_STRING:
-      *(char **)cl->cur_arg->value = arg;
+      *(char **)cl->cur_arg->value = str;
       break;
   }
 
   cl->state = normal_state;
 }
 
-static void normal_state(gpr_cmdline *cl, char *arg) {
+static void normal_state(gpr_cmdline *cl, char *str) {
   char *eq = NULL;
   char *tmp = NULL;
   char *arg_name = NULL;
 
-  if (0 == strcmp(arg, "-help") || 0 == strcmp(arg, "--help") ||
-      0 == strcmp(arg, "-h")) {
+  if (0 == strcmp(str, "-help") || 0 == strcmp(str, "--help") ||
+      0 == strcmp(str, "-h")) {
     print_usage_and_die(cl);
   }
 
   cl->cur_arg = NULL;
 
-  if (arg[0] == '-') {
-    if (arg[1] == '-') {
-      if (arg[2] == 0) {
+  if (str[0] == '-') {
+    if (str[1] == '-') {
+      if (str[2] == 0) {
         /* handle '--' to move to just extra args */
         cl->state = extra_state;
         return;
       }
-      arg += 2;
+      str += 2;
     } else {
-      arg += 1;
+      str += 1;
     }
-    /* first byte of arg is now past the leading '-' or '--' */
-    if (arg[0] == 'n' && arg[1] == 'o' && arg[2] == '-') {
-      /* arg is of the form '--no-foo' - it's a flag disable */
-      arg += 3;
-      cl->cur_arg = find_arg(cl, arg);
+    /* first byte of str is now past the leading '-' or '--' */
+    if (str[0] == 'n' && str[1] == 'o' && str[2] == '-') {
+      /* str is of the form '--no-foo' - it's a flag disable */
+      str += 3;
+      cl->cur_arg = find_arg(cl, str);
       if (cl->cur_arg->type != ARGTYPE_BOOL) {
-        fprintf(stderr, "%s is not a flag argument\n", arg);
+        fprintf(stderr, "%s is not a flag argument\n", str);
         print_usage_and_die(cl);
       }
       *(int *)cl->cur_arg->value = 0;
       return; /* early out */
     }
-    eq = strchr(arg, '=');
+    eq = strchr(str, '=');
     if (eq != NULL) {
       /* copy the string into a temp buffer and extract the name */
-      tmp = arg_name = gpr_malloc((size_t)(eq - arg + 1));
-      memcpy(arg_name, arg, (size_t)(eq - arg));
-      arg_name[eq - arg] = 0;
+      tmp = arg_name = gpr_malloc((size_t)(eq - str + 1));
+      memcpy(arg_name, str, (size_t)(eq - str));
+      arg_name[eq - str] = 0;
     } else {
-      arg_name = arg;
+      arg_name = str;
     }
     cl->cur_arg = find_arg(cl, arg_name);
     if (eq != NULL) {
-      /* arg was of the type --foo=value, parse the value */
+      /* str was of the type --foo=value, parse the value */
       value_state(cl, eq + 1);
     } else if (cl->cur_arg->type != ARGTYPE_BOOL) {
       /* flag types don't have a '--foo value' variant, other types do */
@@ -305,7 +305,7 @@
       *(int *)cl->cur_arg->value = 1;
     }
   } else {
-    extra_state(cl, arg);
+    extra_state(cl, str);
   }
 
   gpr_free(tmp);
diff --git a/src/core/surface/call.c b/src/core/surface/call.c
index 4168c2e..21911ab 100644
--- a/src/core/surface/call.c
+++ b/src/core/surface/call.c
@@ -1473,18 +1473,18 @@
 
   is_trailing = call->read_state >= READ_STATE_GOT_INITIAL_METADATA;
   for (l = md->list.head; l != NULL; l = l->next) {
-    grpc_mdelem *md = l->md;
-    grpc_mdstr *key = md->key;
+    grpc_mdelem *mdel = l->md;
+    grpc_mdstr *key = mdel->key;
     if (key == grpc_channel_get_status_string(call->channel)) {
-      set_status_code(call, STATUS_FROM_WIRE, decode_status(md));
+      set_status_code(call, STATUS_FROM_WIRE, decode_status(mdel));
     } else if (key == grpc_channel_get_message_string(call->channel)) {
-      set_status_details(call, STATUS_FROM_WIRE, GRPC_MDSTR_REF(md->value));
+      set_status_details(call, STATUS_FROM_WIRE, GRPC_MDSTR_REF(mdel->value));
     } else if (key ==
                grpc_channel_get_compression_algorithm_string(call->channel)) {
-      set_compression_algorithm(call, decode_compression(md));
+      set_compression_algorithm(call, decode_compression(mdel));
     } else if (key == grpc_channel_get_encodings_accepted_by_peer_string(
                           call->channel)) {
-      set_encodings_accepted_by_peer(call, md->value->slice);
+      set_encodings_accepted_by_peer(call, mdel->value->slice);
     } else {
       dest = &call->buffered_metadata[is_trailing];
       if (dest->count == dest->capacity) {
@@ -1493,9 +1493,9 @@
             gpr_realloc(dest->metadata, sizeof(grpc_metadata) * dest->capacity);
       }
       mdusr = &dest->metadata[dest->count++];
-      mdusr->key = grpc_mdstr_as_c_string(md->key);
-      mdusr->value = grpc_mdstr_as_c_string(md->value);
-      mdusr->value_length = GPR_SLICE_LENGTH(md->value->slice);
+      mdusr->key = grpc_mdstr_as_c_string(mdel->key);
+      mdusr->value = grpc_mdstr_as_c_string(mdel->value);
+      mdusr->value_length = GPR_SLICE_LENGTH(mdel->value->slice);
       if (call->owned_metadata_count == call->owned_metadata_capacity) {
         call->owned_metadata_capacity =
             GPR_MAX(call->owned_metadata_capacity + 8,
@@ -1504,8 +1504,8 @@
             gpr_realloc(call->owned_metadata,
                         sizeof(grpc_mdelem *) * call->owned_metadata_capacity);
       }
-      call->owned_metadata[call->owned_metadata_count++] = md;
-      l->md = 0;
+      call->owned_metadata[call->owned_metadata_count++] = mdel;
+      l->md = NULL;
     }
   }
   if (gpr_time_cmp(md->deadline, gpr_inf_future(md->deadline.clock_type)) !=
diff --git a/src/core/surface/secure_channel_create.c b/src/core/surface/secure_channel_create.c
index 9b554ee..6eb31ad 100644
--- a/src/core/surface/secure_channel_create.c
+++ b/src/core/surface/secure_channel_create.c
@@ -191,7 +191,7 @@
   grpc_arg connector_arg;
   grpc_channel_args *args_copy;
   grpc_channel_args *new_args_from_connector;
-  grpc_channel_security_connector *connector;
+  grpc_channel_security_connector *security_connector;
   grpc_mdctx *mdctx;
   grpc_resolver *resolver;
   subchannel_factory *f;
@@ -208,7 +208,7 @@
   }
 
   if (grpc_credentials_create_security_connector(
-          creds, target, args, NULL, &connector, &new_args_from_connector) !=
+          creds, target, args, NULL, &security_connector, &new_args_from_connector) !=
       GRPC_SECURITY_OK) {
     return grpc_lame_client_channel_create(
         target, GRPC_STATUS_INVALID_ARGUMENT,
@@ -216,7 +216,7 @@
   }
   mdctx = grpc_mdctx_create();
 
-  connector_arg = grpc_security_connector_to_arg(&connector->base);
+  connector_arg = grpc_security_connector_to_arg(&security_connector->base);
   args_copy = grpc_channel_args_copy_and_add(
       new_args_from_connector != NULL ? new_args_from_connector : args,
       &connector_arg, 1);
@@ -235,8 +235,8 @@
   gpr_ref_init(&f->refs, 1);
   grpc_mdctx_ref(mdctx);
   f->mdctx = mdctx;
-  GRPC_SECURITY_CONNECTOR_REF(&connector->base, "subchannel_factory");
-  f->security_connector = connector;
+  GRPC_SECURITY_CONNECTOR_REF(&security_connector->base, "subchannel_factory");
+  f->security_connector = security_connector;
   f->merge_args = grpc_channel_args_copy(args_copy);
   f->master = channel;
   GRPC_CHANNEL_INTERNAL_REF(channel, "subchannel_factory");
@@ -249,7 +249,7 @@
                                    resolver);
   GRPC_RESOLVER_UNREF(resolver, "create");
   grpc_subchannel_factory_unref(&f->base);
-  GRPC_SECURITY_CONNECTOR_UNREF(&connector->base, "channel_create");
+  GRPC_SECURITY_CONNECTOR_UNREF(&security_connector->base, "channel_create");
 
   grpc_channel_args_destroy(args_copy);
   if (new_args_from_connector != NULL) {
diff --git a/src/core/surface/server.c b/src/core/surface/server.c
index 3d404f7..126349b 100644
--- a/src/core/surface/server.c
+++ b/src/core/surface/server.c
@@ -298,15 +298,15 @@
  * request_matcher
  */
 
-static void request_matcher_init(request_matcher *request_matcher,
+static void request_matcher_init(request_matcher *rm,
                                  size_t entries) {
-  memset(request_matcher, 0, sizeof(*request_matcher));
-  request_matcher->requests = gpr_stack_lockfree_create(entries);
+  memset(rm, 0, sizeof(*rm));
+  rm->requests = gpr_stack_lockfree_create(entries);
 }
 
-static void request_matcher_destroy(request_matcher *request_matcher) {
-  GPR_ASSERT(gpr_stack_lockfree_pop(request_matcher->requests) == -1);
-  gpr_stack_lockfree_destroy(request_matcher->requests);
+static void request_matcher_destroy(request_matcher *rm) {
+  GPR_ASSERT(gpr_stack_lockfree_pop(rm->requests) == -1);
+  gpr_stack_lockfree_destroy(rm->requests);
 }
 
 static void kill_zombie(void *elem, int success) {
@@ -314,10 +314,10 @@
 }
 
 static void request_matcher_zombify_all_pending_calls(
-    request_matcher *request_matcher) {
-  while (request_matcher->pending_head) {
-    call_data *calld = request_matcher->pending_head;
-    request_matcher->pending_head = calld->pending_next;
+    request_matcher *rm) {
+  while (rm->pending_head) {
+    call_data *calld = rm->pending_head;
+    rm->pending_head = calld->pending_next;
     gpr_mu_lock(&calld->mu_state);
     calld->state = ZOMBIED;
     gpr_mu_unlock(&calld->mu_state);
@@ -405,7 +405,7 @@
 }
 
 static void finish_start_new_rpc(grpc_server *server, grpc_call_element *elem,
-                                 request_matcher *request_matcher) {
+                                 request_matcher *rm) {
   call_data *calld = elem->call_data;
   int request_id;
 
@@ -418,17 +418,17 @@
     return;
   }
 
-  request_id = gpr_stack_lockfree_pop(request_matcher->requests);
+  request_id = gpr_stack_lockfree_pop(rm->requests);
   if (request_id == -1) {
     gpr_mu_lock(&server->mu_call);
     gpr_mu_lock(&calld->mu_state);
     calld->state = PENDING;
     gpr_mu_unlock(&calld->mu_state);
-    if (request_matcher->pending_head == NULL) {
-      request_matcher->pending_tail = request_matcher->pending_head = calld;
+    if (rm->pending_head == NULL) {
+      rm->pending_tail = rm->pending_head = calld;
     } else {
-      request_matcher->pending_tail->pending_next = calld;
-      request_matcher->pending_tail = calld;
+      rm->pending_tail->pending_next = calld;
+      rm->pending_tail = calld;
     }
     calld->pending_next = NULL;
     gpr_mu_unlock(&server->mu_call);
@@ -1082,7 +1082,7 @@
 static grpc_call_error queue_call_request(grpc_server *server,
                                           requested_call *rc) {
   call_data *calld = NULL;
-  request_matcher *request_matcher = NULL;
+  request_matcher *rm = NULL;
   int request_id;
   if (gpr_atm_acq_load(&server->shutdown_flag)) {
     fail_call(server, rc);
@@ -1096,22 +1096,22 @@
   }
   switch (rc->type) {
     case BATCH_CALL:
-      request_matcher = &server->unregistered_request_matcher;
+      rm = &server->unregistered_request_matcher;
       break;
     case REGISTERED_CALL:
-      request_matcher = &rc->data.registered.registered_method->request_matcher;
+      rm = &rc->data.registered.registered_method->request_matcher;
       break;
   }
   server->requested_calls[request_id] = *rc;
   gpr_free(rc);
-  if (gpr_stack_lockfree_push(request_matcher->requests, request_id)) {
+  if (gpr_stack_lockfree_push(rm->requests, request_id)) {
     /* this was the first queued request: we need to lock and start
        matching calls */
     gpr_mu_lock(&server->mu_call);
-    while ((calld = request_matcher->pending_head) != NULL) {
-      request_id = gpr_stack_lockfree_pop(request_matcher->requests);
+    while ((calld = rm->pending_head) != NULL) {
+      request_id = gpr_stack_lockfree_pop(rm->requests);
       if (request_id == -1) break;
-      request_matcher->pending_head = calld->pending_next;
+      rm->pending_head = calld->pending_next;
       gpr_mu_unlock(&server->mu_call);
       gpr_mu_lock(&calld->mu_state);
       if (calld->state == ZOMBIED) {
@@ -1160,12 +1160,12 @@
 }
 
 grpc_call_error grpc_server_request_registered_call(
-    grpc_server *server, void *rm, grpc_call **call, gpr_timespec *deadline,
+    grpc_server *server, void *rmp, grpc_call **call, gpr_timespec *deadline,
     grpc_metadata_array *initial_metadata, grpc_byte_buffer **optional_payload,
     grpc_completion_queue *cq_bound_to_call,
     grpc_completion_queue *cq_for_notification, void *tag) {
   requested_call *rc = gpr_malloc(sizeof(*rc));
-  registered_method *registered_method = rm;
+  registered_method *rm = rmp;
   if (!grpc_cq_is_server_cq(cq_for_notification)) {
     gpr_free(rc);
     return GRPC_CALL_ERROR_NOT_SERVER_COMPLETION_QUEUE;
@@ -1177,7 +1177,7 @@
   rc->cq_bound_to_call = cq_bound_to_call;
   rc->cq_for_notification = cq_for_notification;
   rc->call = call;
-  rc->data.registered.registered_method = registered_method;
+  rc->data.registered.registered_method = rm;
   rc->data.registered.deadline = deadline;
   rc->data.registered.initial_metadata = initial_metadata;
   rc->data.registered.optional_payload = optional_payload;