Auto merge of #199 - fitzgen:replace-template-alias, r=emilio
Auto merge of #199 - fitzgen:replace-template-alias, r=emilio

Do not overwrite existing replacements

It turns out that we can end up overwriting existing replacements. This commit embeds the assumption that the first replacement definition is the correct one, and warns on all attempts to overwrite the first replacement definition with a new one. Additionally, it adds some debug logging about replacements.

This actually isn't enough to fix the test case in #89, but it is a good start.

r? @emilio

emilio/rust-bindgen,rust-lang/rust-bindgen,rust-lang/rust-bindgen,emilio/rust-bindgen,jdub/rust-bindgen,jdub/rust-bindgen,emilio/rust-bindgen,rust-lang/rust-bindgen,rust-lang/rust-bindgen,jdub/rust-bindgen,emilio/rust-bindgen,emilio/rust-bindgen,jdub/rust-bindgen