diff --git a/Cargo.toml b/Cargo.toml
index 1529c86..929314e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -46,4 +46,10 @@
 # section. You need to delete this section and then publish with --allow-dirty.
 # A PR https://github.com/rust-lang/cargo/pull/6535 proposes to make it no
 # longer an error to publish with a patch section.
+#
+# Travis builds that are in progress at the time that you publish may spuriously
+# fail. This is because they'll be building a local proc-macro2 which carries
+# the second-most-recent version number, pulling in quote which resolves to a
+# dependency on the just-published most recent version number. Thus the patch
+# will fail to apply because the version numbers are different.
 proc-macro2 = { path = "." }