Hi,

Rust after this patch is not reproducible.

Binary files /gnu/store/nbyxci7zgv9z5zrkzw9c5wppgv3bk1rd-rust-1.24.1/lib/librustc-7b5ea53516e6ab59.so and /gnu/store/nbyxci7zgv9z5zrkzw9c5wppgv3bk1rd-rust-1.24.1-check/lib/librustc-7b5ea53516e6ab59.so differ
Binary files /gnu/store/nbyxci7zgv9z5zrkzw9c5wppgv3bk1rd-rust-1.24.1/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc-7b5ea53516e6ab59.so and /gnu/store/nbyxci7zgv9z5zrkzw9c5wppgv3bk1rd-rust-1.24.1-check/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc-7b5ea53516e6ab59.so differ

diffoscope says:

│ │ │ -  [26] .rustc            PROGBITS        0000000000000000 be3030 6e5dd5 00      0   0 16
│ │ │ -  [27] .symtab           SYMTAB          0000000000000000 12c8e08 158340 18     28 54351  8
│ │ │ -  [28] .strtab           STRTAB          0000000000000000 1421148 3b00e3 00      0   0  1
│ │ │ -  [29] .shstrtab         STRTAB          0000000000000000 17d122b 0000fe 00      0   0  1
│ │ │ +  [26] .rustc            PROGBITS        0000000000000000 be3030 6e6b05 00      0   0 16
│ │ │ +  [27] .symtab           SYMTAB          0000000000000000 12c9b38 158340 18     28 54351  8
│ │ │ +  [28] .strtab           STRTAB          0000000000000000 1421e78 3b00e3 00      0   0  1
│ │ │ +  [29] .shstrtab         STRTAB          0000000000000000 17d1f5b 0000fe 00      0   0  1
│ │ │  Key to Flags:
[...]
│ │ │ -  1603: 0000000000000000 0x6e5dd5 OBJECT  GLOBAL DEFAULT   26 rust_metadata_rustc_d87c35d223a98218627136b41e7e5b87
│ │ │ +  1603: 0000000000000000 0x6e6b05 OBJECT  GLOBAL DEFAULT   26 rust_metadata_rustc_d87c35d223a98218627136b41e7e5b87

And a metadata body part is missing in the second round.