diff --git a/src/bootstrap/src/core/build_steps/test.rs b/src/bootstrap/src/core/build_steps/test.rs index dcbaf20796f..870fe6a9f16 100644 --- a/src/bootstrap/src/core/build_steps/test.rs +++ b/src/bootstrap/src/core/build_steps/test.rs @@ -1735,6 +1735,14 @@ NOTE: if you're sure you want to do this, please open an issue as to why. In the builder.initial_cargo.clone() } else { // We need to properly build cargo using the suitable stage compiler. + + // HACK: currently tool stages are off-by-one compared to compiler stages, i.e. if + // you give `tool::Cargo` a stage 1 rustc, it will cause stage 2 rustc to be built + // and produce a cargo built with stage 2 rustc. To fix this, we need to chop off + // the compiler stage by 1 to align with expected `./x test run-make --stage N` + // behavior, i.e. we need to pass `N - 1` compiler stage to cargo. See also Miri + // which does a similar hack. + let compiler = builder.compiler(builder.top_stage - 1, compiler.host); builder.ensure(tool::Cargo { compiler, target: compiler.host }) };