Add closure allocations check to CI

.travis.yml

@@ -44,6 +44,11 @@ jobs:
           env: DMD=2.070.2.s* F=devel
 
         # Additional stages
+        #
+        - stage: Closure allocation check
+          env: DMD=2.070.2.s* F=devel
+          install: beaver dlang install
+          script: ci/closures.sh
 
         - stage: D2 Release
           if: tag IS present AND NOT tag =~ \+d2$

ci/closures.sh

@@ -0,0 +1,12 @@
+#!/bin/sh
+set -xe
+
+# Enables printing of all potential GC allocation sources to stdout
+export DFLAGS=-vgc
+
+# Prepare sources
+beaver dlang make d2conv
+
+# Ensure that there are no lines about closure allocations in the output
+# Filters away errors from submodules to focus on swarm own code only
+! beaver dlang make fasttest 2>&1 | grep "\./src/.*\<closure\>"