This reverts commit a034f87146e60e1db2327c6f6807c47406a1bb0b. Conflicts: src/comp/middle/check_alt.rs src/comp/middle/trans_alt.rs src/comp/syntax/ast.rs src/comp/syntax/ast_util.rs src/comp/syntax/fold.rs src/comp/syntax/print/pprust.rs Conflicts: src/comp/middle/trans_alt.rs
This reverts commit ce0f054f9d56df4e60291fc2e1b89ce979cf374f.