diff --git a/mk/tests.mk b/mk/tests.mk
index be1d3ac057c..e6b9bffa03e 100644
--- a/mk/tests.mk
+++ b/mk/tests.mk
@@ -261,6 +261,15 @@ tidy:
 		| xargs -n 10 $(CFG_PYTHON) $(S)src/etc/tidy.py
 		$(Q)echo $(ALL_HS) \
 		| xargs -n 10 $(CFG_PYTHON) $(S)src/etc/tidy.py
+		$(Q)find $(S)src -type f -perm +111 \
+		    -not -name '*.rs' -and -not -name '*.py' \
+		    -and -not -name '*.sh' \
+		| grep '^$(S)src/llvm' -v \
+		| grep '^$(S)src/libuv' -v \
+		| grep '^$(S)src/gyp' -v \
+		| grep '^$(S)src/etc' -v \
+		| grep '^$(S)src/rt/jemalloc' -v \
+		| xargs $(CFG_PYTHON) $(S)src/etc/check-binaries.py
 
 endif
 
diff --git a/src/etc/check-binaries.py b/src/etc/check-binaries.py
new file mode 100755
index 00000000000..ebd2a9376b6
--- /dev/null
+++ b/src/etc/check-binaries.py
@@ -0,0 +1,18 @@
+# Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+# file at the top-level directory of this distribution and at
+# http://rust-lang.org/COPYRIGHT.
+#
+# Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+# http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+# <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+# option. This file may not be copied, modified, or distributed
+# except according to those terms.
+
+import sys
+
+offenders = sys.argv[1:]
+if len(offenders) > 0:
+    print("Binaries checked into src:")
+    for offender in offenders:
+        print(offender)
+    sys.exit(1)
diff --git a/src/libsyntax/syntax b/src/libsyntax/syntax
deleted file mode 100755
index 942ee88bd0e..00000000000
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diff --git a/src/rt/sundown/html/html.c b/src/rt/sundown/html/html.c
old mode 100755
new mode 100644
diff --git a/src/test/compile-fail/issue-3763 b/src/test/compile-fail/issue-3763
deleted file mode 100755
index 4415d099181..00000000000
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diff --git a/src/test/compile-fail/liveness-unused b/src/test/compile-fail/liveness-unused
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diff --git a/src/test/run-pass/issue-3559 b/src/test/run-pass/issue-3559
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index 505b9b65512..00000000000
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diff --git a/src/test/run-pass/issue-3702 b/src/test/run-pass/issue-3702
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diff --git a/src/test/run-pass/issue-4016 b/src/test/run-pass/issue-4016
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diff --git a/src/test/run-pass/issue-4092 b/src/test/run-pass/issue-4092
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