Problems for source package rust-async-backtrace

BuildDepends

Package declares a build time dependency on librust-loom-0.5+default-dev (>= 0.5.6-~~) <!nocheck> which cannot be satisfied on armhf. Package rust-async-backtrace does not exist on armhf.
Package declares a build time dependency on librust-loom-0.5+default-dev (>= 0.5.6-~~) <!nocheck> which cannot be satisfied on ppc64el. Package rust-async-backtrace does not exist on ppc64el.
Package declares a build time dependency on librust-loom-0.5+default-dev (>= 0.5.6-~~) <!nocheck> which cannot be satisfied on mips64el. Package rust-async-backtrace does not exist on mips64el.
Package declares a build time dependency on librust-loom-0.5+default-dev (>= 0.5.6-~~) <!nocheck> which cannot be satisfied on armel. Package rust-async-backtrace does not exist on armel.
Package declares a build time dependency on librust-loom-0.5+default-dev (>= 0.5.6-~~) <!nocheck> which cannot be satisfied on s390x. Package rust-async-backtrace does not exist on s390x.
Package declares a build time dependency on librust-loom-0.5+default-dev (>= 0.5.6-~~) <!nocheck> which cannot be satisfied on i386. Package rust-async-backtrace does not exist on i386.

Malformed Build-Depends

Package declares a build time dependency on 'cargo:native <!nocheck>' which is broken Syntax.
Package declares a build time dependency on 'rustc:native <!nocheck>' which is broken Syntax.