Before the recent changes to rustbuild, when changing `libcompiler_builtins/lib.rs`, it has rebuilt the entire stage0 artifacts and thus the entire compiler. Now its only doing: ``` Finished debug [unoptimized] target(s) in 0.0 secs Synchronisiere Submodul-URL für 'src/compiler-rt' Synchronisiere Submodul-URL für 'src/jemalloc' Synchronisiere Submodul-URL für 'src/liblibc' Synchronisiere Submodul-URL für 'src/llvm' Synchronisiere Submodul-URL für 'src/rt/hoedown' Synchronisiere Submodul-URL für 'src/rust-installer' HEAD ist jetzt bei a8fc4c1 Merge pull request #28 from xen0n/preprocessor-firefighting HEAD ist jetzt bei e058ca6 Change how the default zone is found HEAD ist jetzt bei e49e9bb Auto merge of #478 - jackpot51:patch-1, r=alexcrichton HEAD ist jetzt bei ceb177e Merge pull request #60 from japaric/gh38406 HEAD ist jetzt bei a3736a0 Merge pull request #6 from intelfx/patch-1 HEAD ist jetzt bei 4f99485 Merge pull request #54 from brson/docdir Building stage0 std artifacts (i686-unknown-linux-gnu -> i686-unknown-linux-gnu) Compiling compiler_builtins v0.0.0 (file://rust/src/libcompiler_builtins) Compiling std v0.0.0 (file://rust/src/libstd) Compiling std_shim v0.1.0 (file://rust/src/rustc/std_shim) Finished release [optimized] target(s) in 9.0 secs Copying stage0 std from stage0 (i686-unknown-linux-gnu -> i686-unknown-linux-gnu / i686-unknown-linux-gnu) Building stage0 test artifacts (i686-unknown-linux-gnu -> i686-unknown-linux-gnu) Finished release [optimized] target(s) in 0.0 secs Copying stage0 test from stage0 (i686-unknown-linux-gnu -> i686-unknown-linux-gnu / i686-unknown-linux-gnu) Building stage0 compiler artifacts (i686-unknown-linux-gnu -> i686-unknown-linux-gnu) Finished release [optimized] target(s) in 0.0 secs Copying stage0 rustc from stage0 (i686-unknown-linux-gnu -> i686-unknown-linux-gnu / i686-unknown-linux-gnu) Copying stage1 compiler (i686-unknown-linux-gnu) Building stage1 std artifacts (i686-unknown-linux-gnu -> i686-unknown-linux-gnu) Compiling compiler_builtins v0.0.0 (file://rust/src/libcompiler_builtins) Compiling std v0.0.0 (file://rust/src/libstd) Compiling std_shim v0.1.0 (file://rust/src/rustc/std_shim) Finished release [optimized] target(s) in 10.10 secs Copying stage1 std from stage1 (i686-unknown-linux-gnu -> i686-unknown-linux-gnu / i686-unknown-linux-gnu) Building stage1 test artifacts (i686-unknown-linux-gnu -> i686-unknown-linux-gnu) Finished release [optimized] target(s) in 0.0 secs Copying stage1 test from stage1 (i686-unknown-linux-gnu -> i686-unknown-linux-gnu / i686-unknown-linux-gnu) Building stage1 compiler artifacts (i686-unknown-linux-gnu -> i686-unknown-linux-gnu) Finished release [optimized] target(s) in 0.0 secs Copying stage1 rustc from stage1 (i686-unknown-linux-gnu -> i686-unknown-linux-gnu / i686-unknown-linux-gnu) Copying stage2 compiler (i686-unknown-linux-gnu) Copying stage2 std from stage1 (i686-unknown-linux-gnu -> i686-unknown-linux-gnu / i686-unknown-linux-gnu) Copying stage2 test from stage1 (i686-unknown-linux-gnu -> i686-unknown-linux-gnu / i686-unknown-linux-gnu) Building stage2 tool compiletest (i686-unknown-linux-gnu) Finished release [optimized] target(s) in 0.0 secs Check compiletest suite=run-pass mode=run-pass (i686-unknown-linux-gnu -> i686-unknown-linux-gnu) ``` Later on, you are getting an error like "found possibly newer version of crate `compiler_builtins` which `test` depends on".