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| author | Brian Anderson <banderson@mozilla.com> | 2011-10-16 16:19:12 -0700 |
|---|---|---|
| committer | Brian Anderson <banderson@mozilla.com> | 2011-10-20 18:23:48 -0700 |
| commit | 391e12124b4ee96849b8b5959c2cab824400a384 (patch) | |
| tree | 3fa064c4121e80f29bdd779575f29707e5f61201 /src/comp | |
| parent | 342a400e79c44e8035b944129617734009a5abcb (diff) | |
| download | rust-391e12124b4ee96849b8b5959c2cab824400a384.tar.gz rust-391e12124b4ee96849b8b5959c2cab824400a384.zip | |
Tweak typecheck to enforce covariance on higher-order function arguments
Diffstat (limited to 'src/comp')
| -rw-r--r-- | src/comp/middle/ty.rs | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/src/comp/middle/ty.rs b/src/comp/middle/ty.rs index 71521abb538..84532e718e5 100644 --- a/src/comp/middle/ty.rs +++ b/src/comp/middle/ty.rs @@ -2004,8 +2004,11 @@ mod unify { (ures_err(terr_mode_mismatch(expected_input.mode, actual_input.mode))); } else { expected_input.mode }; + // The variance changes (flips basically) when descending + // into arguments of function types let result = unify_step( - cx, expected_input.ty, actual_input.ty, variance); + cx, expected_input.ty, actual_input.ty, + variance_transform(variance, contravariant)); alt result { ures_ok(rty) { result_ins += [{mode: result_mode, ty: rty}]; } _ { ret fn_common_res_err(result); } |