diff --git a/src/etc/_cargo b/src/etc/_cargo
index 1c8c413f16c..12694901ed0 100644
--- a/src/etc/_cargo
+++ b/src/etc/_cargo
@@ -3,426 +3,340 @@
 autoload -U regexp-replace
 
 _cargo() {
-    local state
+    local curcontext="$curcontext" ret=1
+    local -a command_scope_spec common parallel features msgfmt triple target registry
+    local -a state line state_descr # These are set by _arguments
     typeset -A opt_args
 
+    common=(
+        '(-q --quiet)*'{-v,--verbose}'[use verbose output]'
+        '(-q --quiet -v --verbose)'{-q,--quiet}'[no output printed to stdout]'
+        '-Z+[pass unstable (nightly-only) flags to cargo]: :_cargo_unstable_flags'
+        '--frozen[require that Cargo.lock and cache are up-to-date]'
+        '--locked[require that Cargo.lock is up-to-date]'
+        '--color=[specify colorization option]:coloring:(auto always never)'
+        '(- 1 *)'{-h,--help}'[show help message]'
+    )
+
     # leading items in parentheses are an exclusion list for the arguments following that arg
     # See: http://zsh.sourceforge.net/Doc/Release/Completion-System.html#Completion-Functions
     #   - => exclude all other options
     #   1 => exclude positional arg 1
     #   * => exclude all other args
     #   +blah => exclude +blah
-    _arguments \
-        '(- 1 *)'{-h,--help}'[show help message]' \
+    _arguments -s -S -C $common \
         '(- 1 *)--list[list installed commands]' \
+        '(- 1 *)--explain=[provide a detailed explanation of an error message]:error code' \
         '(- 1 *)'{-V,--version}'[show version information]' \
-        {-v,--verbose}'[use verbose output]' \
-        --color'[colorization option]' \
         '(+beta +nightly)+stable[use the stable toolchain]' \
         '(+stable +nightly)+beta[use the beta toolchain]' \
         '(+stable +beta)+nightly[use the nightly toolchain]' \
         '1: :_cargo_cmds' \
         '*:: :->args'
 
+    # These flags are mutually exclusive specifiers for the scope of a command; as
+    # they are used in multiple places without change, they are expanded into the
+    # appropriate command's `_arguments` where appropriate.
+    command_scope_spec=(
+        '(--bin --example --test --lib)--bench=[specify benchmark name]: :_cargo_benchmark_names'
+        '(--bench --bin --test --lib)--example=[specify example name]:example name'
+        '(--bench --example --test --lib)--bin=[specify binary name]:binary name'
+        '(--bench --bin --example --test)--lib=[specify library name]:library name'
+        '(--bench --bin --example --lib)--test=[specify test name]:test name'
+    )
+
+    parallel=(
+        '(-j --jobs)'{-j+,--jobs=}'[specify number of parallel jobs]:jobs [# of CPUs]'
+    )
+
+    features=(
+        '(--all-features)--features=[specify features to activate]:feature'
+        '(--features)--all-features[activate all available features]'
+        "--no-default-features[don't build the default features]"
+    )
+
+    msgfmt='--message-format=[specify error format]:error format [human]:(human json short)'
+    triple='--target=[specify target triple]:target triple'
+    target='--target-dir=[specify directory for all generated artifacts]:directory:_directories'
+    manifest='--manifest-path=[specify path to manifest]:path:_directories'
+    registry='--registry=[specify registry to use]:registry'
+
     case $state in
         args)
+            curcontext="${curcontext%:*}-${words[1]}:"
             case ${words[1]} in
                 bench)
-                    _arguments \
-                        '--features=[space separated feature list]' \
-                        '--all-features[enable all available features]' \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '(-j, --jobs)'{-j,--jobs}'[number of parallel jobs, defaults to # of CPUs]' \
+                    _arguments -s -A "^--" $common $parallel $features $msgfmt $triple $target $manifest \
                         "${command_scope_spec[@]}" \
-                        '--manifest-path=[path to manifest]: :_files -/' \
-                        '--no-default-features[do not build the default features]' \
-                        '--no-run[compile but do not run]' \
-                        '(-p,--package)'{-p=,--package=}'[package to run benchmarks for]:packages:_get_package_names' \
-                        '--target=[target triple]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '--color=:colorization option:(auto always never)' \
+                        '--all-targets[benchmark all targets]' \
+                        "--no-run[compile but don't run]" \
+                        '(-p --package)'{-p+,--package=}'[specify package to run benchmarks for]:package:_cargo_package_names' \
+                        '--exclude=[exclude packages from the benchmark]:spec' \
+                        '--no-fail-fast[run all benchmarks regardless of failure]' \
+                        '1: :_guard "^-*" "bench name"' \
+                        '*:args:_default'
                         ;;
 
                 build)
-                    _arguments \
-                        '--features=[space separated feature list]' \
-                        '--all-features[enable all available features]' \
+                    _arguments -s -S $common $parallel $features $msgfmt $triple $target $manifest \
                         '--all-targets[equivalent to specifying --lib --bins --tests --benches --examples]' \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '(-j, --jobs)'{-j,--jobs}'[number of parallel jobs, defaults to # of CPUs]' \
                         "${command_scope_spec[@]}" \
-                        '--manifest-path=[path to manifest]: :_files -/' \
-                        '--no-default-features[do not build the default features]' \
-                        '(-p,--package)'{-p=,--package=}'[package to build]:packages:_get_package_names' \
-                        '--release=[build in release mode]' \
-                        '--target=[target triple]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '--color=:colorization option:(auto always never)' \
+                        '(-p --package)'{-p+,--package=}'[specify package to build]:package:_cargo_package_names' \
+                        '--release[build in release mode]' \
+                        '--build-plan[output the build plan in JSON]' \
                         ;;
 
                 check)
-                    _arguments \
-                        '--features=[space separated feature list]' \
-                        '--all-features[enable all available features]' \
+                    _arguments -s -S $common $parallel $features $msgfmt $triple $target $manifest \
                         '--all-targets[equivalent to specifying --lib --bins --tests --benches --examples]' \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '(-j, --jobs)'{-j,--jobs}'[number of parallel jobs, defaults to # of CPUs]' \
                         "${command_scope_spec[@]}" \
-                        '--manifest-path=[path to manifest]: :_files -/' \
-                        '--no-default-features[do not check the default features]' \
-                        '(-p,--package)'{-p=,--package=}'[package to check]:packages:_get_package_names' \
-                        '--release=[check in release mode]' \
-                        '--target=[target triple]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '--color=:colorization option:(auto always never)' \
+                        '(-p --package)'{-p+,--package=}'[specify package to check]:package:_cargo_package_names' \
+                        '--release[check in release mode]' \
                         ;;
 
                 clean)
-                    _arguments \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '--manifest-path=[path to manifest]: :_files -/' \
-                        '(-p,--package)'{-p=,--package=}'[package to clean]:packages:_get_package_names' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '--release[whether or not to clean release artifacts]' \
-                        '--target=[target triple(default:all)]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--color=:colorization option:(auto always never)' \
+                    _arguments -s -S $common $triple $target $manifest \
+                        '(-p --package)'{-p+,--package=}'[specify package to clean]:package:_cargo_package_names' \
+                        '--release[clean release artifacts]' \
+                        '--doc[clean just the documentation directory]'
                         ;;
 
                 doc)
-                    _arguments \
-                        '--features=[space separated feature list]' \
-                        '--all-features[enable all available features]' \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '(-j, --jobs)'{-j,--jobs}'[number of parallel jobs, defaults to # of CPUs]' \
-                        '--manifest-path=[path to manifest]: :_files -/' \
+                    _arguments -s -S $common $parallel $features $msgfmt $triple $target $manifest \
                         '--no-deps[do not build docs for dependencies]' \
-                        '--no-default-features[do not build the default features]' \
                         '--document-private-items[include non-public items in the documentation]' \
                         '--open[open docs in browser after the build]' \
-                        '(-p, --package)'{-p,--package}'=[package to document]' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
+                        '(-p --package)'{-p+,--package=}'[specify package to document]:package:_cargo_package_names' \
                         '--release[build artifacts in release mode, with optimizations]' \
-                        '--target=[build for the target triple]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--color=:colorization option:(auto always never)' \
                         ;;
 
                 fetch)
-                    _arguments \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '--manifest-path=[path to manifest]: :_files -/' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--color=:colorization option:(auto always never)' \
+                    _arguments -s -S $common $triple $manifest
                         ;;
 
+                fix)
+                    _arguments -s -S $common $parallel $features $msgfmt $triple $target $manifest \
+                        "${command_scope_spec[@]}" \
+                        '--broken-code[fix code even if it already has compiler errors]' \
+                        '--edition[fix in preparation for the next edition]' \
+                        '--edition-idioms[fix warnings to migrate to the idioms of an edition]' \
+                        '--allow-no-vcs[fix code even if a VCS was not detected]' \
+                        '--allow-dirty[fix code even if the working directory is dirty]' \
+                        '--allow-staged[fix code even if the working directory has staged changes]'
+                ;;
+
                 generate-lockfile)
-                    _arguments \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '--manifest-path=[path to manifest]: :_files -/' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--color=:colorization option:(auto always never)' \
+                    _arguments -s -S $common $manifest
                         ;;
 
                 git-checkout)
-                    _arguments \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '--reference=[REF]' \
-                        '--url=[URL]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--color=:colorization option:(auto always never)' \
+                    _arguments -s -S $common \
+                        '--reference=:reference' \
+                        '--url=:url:_urls'
                         ;;
 
                 help)
-                    _arguments \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '*: :_cargo_cmds' \
+                    _cargo_cmds
                         ;;
 
                 init)
-                    _arguments \
+                    _arguments -s -S $common $registry \
                         '--lib[use library template]' \
-                        '--vcs:initialize a new repo with a given VCS:(git hg none)' \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '--name=[set the resulting package name]' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--color=:colorization option:(auto always never)' \
+                        '--edition=[specify edition to set for the crate generated]:edition:(2015 2018)' \
+                        '--vcs=[initialize a new repo with a given VCS]:vcs:(git hg pijul fossil none)' \
+                        '--name=[set the resulting package name]:name' \
+                        '1:path:_directories'
                         ;;
 
                 install)
-                    _arguments \
-                        '--bin=[only install the specified binary]' \
-                        '--branch=[branch to use when installing from git]' \
-                        '--color=:colorization option:(auto always never)' \
+                    _arguments -s -S $common $parallel $features $triple $registry \
+                        '(-f --force)'{-f,--force}'[force overwriting of existing crates or binaries]' \
+                        '--bin=[only install the specified binary]:binary' \
+                        '--branch=[branch to use when installing from git]:branch' \
                         '--debug[build in debug mode instead of release mode]' \
-                        '--example[install the specified example instead of binaries]' \
-                        '--features=[space separated feature list]' \
-                        '--all-features[enable all available features]' \
-                        '--git=[URL from which to install the crate]' \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '(-j, --jobs)'{-j,--jobs}'[number of parallel jobs, defaults to # of CPUs]' \
-                        '--no-default-features[do not build the default features]' \
-                        '--path=[local filesystem path to crate to install]: :_files -/' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '--rev=[specific commit to use when installing from git]' \
-                        '--root=[directory to install packages into]: :_files -/' \
-                        '--tag=[tag to use when installing from git]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--vers=[version to install from crates.io]' \
+                        '--example=[install the specified example instead of binaries]:example' \
+                        '--git=[specify URL from which to install the crate]:url:_urls' \
+                        '--path=[local filesystem path to crate to install]: :_directories' \
+                        '--rev=[specific commit to use when installing from git]:commit' \
+                        '--root=[directory to install packages into]: :_directories' \
+                        '--tag=[tag to use when installing from git]:tag' \
+                        '--vers=[version to install from crates.io]:version' \
+                        '--list[list all installed packages and their versions]' \
+                        '*: :_guard "^-*" "crate"'
                         ;;
 
                 locate-project)
-                    _arguments \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '--manifest-path=[path to manifest]: :_files -/' \
+                    _arguments -s -S $common $manifest
                         ;;
 
                 login)
-                    _arguments \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '--host=[Host to set the token for]' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--color=:colorization option:(auto always never)' \
+                    _arguments -s -S $common $registry \
+                        '*: :_guard "^-*" "token"'
                         ;;
 
                 metadata)
-                    _arguments \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
+                    _arguments -s -S $common $features $manifest \
                         "--no-deps[output information only about the root package and don't fetch dependencies]" \
-                        '--no-default-features[do not include the default feature]' \
-                        '--manifest-path=[path to manifest]: :_files -/' \
-                        '--features=[space separated feature list]' \
-                        '--all-features[enable all available features]' \
-                        '--format-version=[format version(default: 1)]' \
-                        '--color=:colorization option:(auto always never)' \
+                        '--format-version=[specify format version]:version [1]:(1)'
                         ;;
 
                 new)
-                    _arguments \
+                    _arguments -s -S $common $registry \
                         '--lib[use library template]' \
                         '--vcs:initialize a new repo with a given VCS:(git hg none)' \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '--name=[set the resulting package name]' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--color=:colorization option:(auto always never)' \
+                        '--name=[set the resulting package name]'
                         ;;
 
                 owner)
-                    _arguments \
-                        '(-a, --add)'{-a,--add}'[add owner LOGIN]' \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '--index[registry index]' \
-                        '(-l, --list)'{-l,--list}'[list owners of a crate]' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '(-r, --remove)'{-r,--remove}'[remove owner LOGIN]' \
-                        '--token[API token to use when authenticating]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--color=:colorization option:(auto always never)' \
+                    _arguments -s -S $common $registry \
+                        '(-a --add)'{-a,--add}'[specify name of a user or team to invite as an owner]:name' \
+                        '--index=[specify registry index]:index' \
+                        '(-l --list)'{-l,--list}'[list owners of a crate]' \
+                        '(-r --remove)'{-r,--remove}'[specify name of a user or team to remove as an owner]:name' \
+                        '--token=[specify API token to use when authenticating]:token' \
+                        '*: :_guard "^-*" "crate"'
                         ;;
 
                 package)
-                    _arguments \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '(-l, --list)'{-l,--list}'[print files included in a package without making one]' \
-                        '--manifest-path=[path to manifest]: :_files -/' \
+                    _arguments -s -S $common $parallel $features $triple $target $manifest \
+                        '(-l --list)'{-l,--list}'[print files included in a package without making one]' \
                         '--no-metadata[ignore warnings about a lack of human-usable metadata]' \
-                        '--no-verify[do not build to verify contents]' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--color=:colorization option:(auto always never)' \
+                        '--allow-dirty[allow dirty working directories to be packaged]' \
+                        "--no-verify[don't build to verify contents]"
                         ;;
 
                 pkgid)
-                    _arguments \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '--manifest-path=[path to manifest]: :_files -/' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--color=:colorization option:(auto always never)' \
+                    _arguments -s -S $common $manifest \
+                        '(-p --package)'{-p+,--package=}'[specify package to get ID specifier for]:package:_cargo_package_names' \
+                        '*: :_guard "^-*" "spec"'
                         ;;
 
                 publish)
-                    _arguments \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '--host=[Host to set the token for]' \
-                        '--manifest-path=[path to manifest]: :_files -/' \
-                        '--no-verify[Do not verify tarball until before publish]' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '--token[token to use when uploading]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--color=:colorization option:(auto always never)' \
+                    _arguments -s -S $common $parallel $features $triple $target $manifest $registry \
+                        '--index=[specify registry index]:index' \
+                        '--allow-dirty[allow dirty working directories to be packaged]' \
+                        "--no-verify[don't verify the contents by building them]" \
+                        '--token=[specify token to use when uploading]:token' \
+                        '--dry-run[perform all checks without uploading]'
                         ;;
 
                 read-manifest)
-                    _arguments \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '--manifest-path=[path to manifest]: :_files -/' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--color=:colorization option:(auto always never)' \
+                    _arguments -s -S $common $manifest
                         ;;
 
                 run)
-                    _arguments \
-                        '--example=[name of the bin target]' \
-                        '--features=[space separated feature list]' \
-                        '--all-features[enable all available features]' \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '(-j, --jobs)'{-j,--jobs}'[number of parallel jobs, defaults to # of CPUs]' \
-                        '--manifest-path=[path to manifest]: :_files -/' \
-                        '--bin=[name of the bin target]' \
-                        '--no-default-features[do not build the default features]' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '--release=[build in release mode]' \
-                        '--target=[target triple]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--color=:colorization option:(auto always never)' \
-                        '*: :_normal' \
+                    _arguments -s -S $common $parallel $features $msgfmt $triple $target $manifest \
+                        '--example=[name of the bin target]:name' \
+                        '--bin=[name of the bin target]:name' \
+                        '(-p --package)'{-p+,--package=}'[specify package with the target to run]:package:_cargo_package_names' \
+                        '--release[build in release mode]' \
+                        '*: :_default'
                         ;;
 
                 rustc)
-                    _arguments \
-                        '--color=:colorization option:(auto always never)' \
-                        '--features=[features to compile for the package]' \
-                        '--all-features[enable all available features]' \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '(-j, --jobs)'{-j,--jobs}'=[number of parallel jobs, defaults to # of CPUs]' \
-                        '--manifest-path=[path to the manifest to fetch dependencies for]: :_files -/' \
-                        '--no-default-features[do not compile default features for the package]' \
-                        '(-p, --package)'{-p,--package}'=[profile to compile for]' \
-                        '--profile=[profile to build the selected target for]' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
+                    _arguments -s -S $common $parallel $features $msgfmt $triple $target $manifest \
+                        '(-p --package)'{-p+,--package=}'[specify package to build]:package:_cargo_package_names' \
+                        '--profile=[specify profile to build the selected target for]:profile' \
                         '--release[build artifacts in release mode, with optimizations]' \
-                        '--target=[target triple which compiles will be for]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
                         "${command_scope_spec[@]}" \
+                        '*: : _dispatch rustc rustc -default-'
                         ;;
 
                 rustdoc)
-                    _arguments \
-                        '--color=:colorization option:(auto always never)' \
-                        '--features=[space-separated list of features to also build]' \
-                        '--all-features[enable all available features]' \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '(-j, --jobs)'{-j,--jobs}'=[number of parallel jobs, defaults to # of CPUs]' \
-                        '--manifest-path=[path to the manifest to document]: :_files -/' \
-                        '--no-default-features[do not build the `default` feature]' \
+                    _arguments -s -S $common $parallel $features $msgfmt $triple $target $manifest \
                         '--document-private-items[include non-public items in the documentation]' \
                         '--open[open the docs in a browser after the operation]' \
-                        '(-p, --package)'{-p,--package}'=[package to document]' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
+                        '(-p --package)'{-p+,--package=}'[specify package to document]:package:_cargo_package_names' \
                         '--release[build artifacts in release mode, with optimizations]' \
-                        '--target=[build for the target triple]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
                         "${command_scope_spec[@]}" \
+                        '*: : _dispatch rustdoc rustdoc -default-'
                         ;;
 
                 search)
-                    _arguments \
-                        '--color=:colorization option:(auto always never)' \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '--host=[host of a registry to search in]' \
-                        '--limit=[limit the number of results]' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
+                    _arguments -s -S $common $registry \
+                        '--index=[specify registry index]:index' \
+                        '--limit=[limit the number of results]:results [10]' \
+                        '*: :_guard "^-*" "query"'
                         ;;
 
                 test)
-                    _arguments \
-                        '--features=[space separated feature list]' \
-                        '--all-features[enable all available features]' \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '(-j, --jobs)'{-j,--jobs}'[number of parallel jobs, defaults to # of CPUs]' \
-                        '--manifest-path=[path to manifest]: :_files -/' \
-                        '--test=[test name]: :_test_names' \
-                        '--no-default-features[do not build the default features]' \
+                    _arguments -s -S $common $parallel $features $msgfmt $triple $target $manifest \
+                        '--test=[test name]: :_cargo_test_names' \
                         '--no-fail-fast[run all tests regardless of failure]' \
                         '--no-run[compile but do not run]' \
-                        '(-p,--package)'{-p=,--package=}'[package to run tests for]:packages:_get_package_names' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
+                        '(-p --package)'{-p+,--package=}'[package to run tests for]:package:_cargo_package_names' \
+                        '--all[test all packages in the workspace]' \
                         '--release[build artifacts in release mode, with optimizations]' \
-                        '--target=[target triple]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--color=:colorization option:(auto always never)' \
-                        '1: :_test_names' \
+                        '1: :_cargo_test_names' \
                         '(--doc --bin --example --test --bench)--lib[only test library]' \
                         '(--lib --bin --example --test --bench)--doc[only test documentation]' \
                         '(--lib --doc --example --test --bench)--bin=[binary name]' \
                         '(--lib --doc --bin --test --bench)--example=[example name]' \
                         '(--lib --doc --bin --example --bench)--test=[test name]' \
                         '(--lib --doc --bin --example --test)--bench=[benchmark name]' \
-                        '--message-format:error format:(human json short)' \
-                        '--frozen[require lock and cache up to date]' \
-                        '--locked[require lock up to date]'
+                        '*: :_default'
                         ;;
 
                 uninstall)
-                    _arguments \
-                        '--bin=[only uninstall the binary NAME]' \
-                        '--color=:colorization option:(auto always never)' \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '(-q, --quiet)'{-q,--quiet}'[less output printed to stdout]' \
+                    _arguments -s -S $common \
+                        '(-p --package)'{-p+,--package=}'[specify package to uninstall]:package:_cargo_package_names' \
+                        '--bin=[only uninstall the specified binary]:name' \
                         '--root=[directory to uninstall packages from]: :_files -/' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
+                        '*:crate:_cargo_installed_crates -F line'
                         ;;
 
                 update)
-                    _arguments \
+                    _arguments -s -S $common $manifest \
                         '--aggressive=[force dependency update]' \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '--manifest-path=[path to manifest]: :_files -/' \
-                        '(-p,--package)'{-p=,--package=}'[package to update]:packages:_get_package_names' \
-                        '--precise=[update single dependency to PRECISE]: :' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--color=:colorization option:(auto always never)' \
+                        "--dry-run[don't actually write the lockfile]" \
+                        '(-p --package)'{-p+,--package=}'[specify package to update]:package:_cargo_package_names' \
+                        '--precise=[update single dependency to precise release]:release'
                         ;;
 
                 verify-project)
-                    _arguments \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '--manifest-path=[path to manifest]: :_files -/' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--color=:colorization option:(auto always never)' \
+                    _arguments -s -S $common $manifest
                         ;;
 
                 version)
-                    _arguments \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--color=:colorization option:(auto always never)' \
+                    _arguments -s -S $common
                         ;;
 
                 yank)
-                    _arguments \
-                        '(-h, --help)'{-h,--help}'[show help message]' \
-                        '--index[registry index]' \
-                        '(-q, --quiet)'{-q,--quiet}'[no output printed to stdout]' \
-                        '--token[API token to use when authenticating]' \
+                    _arguments -s -S $common $registry \
+                        '--vers=[specify yank version]:version' \
                         '--undo[undo a yank, putting a version back into the index]' \
-                        '(-v, --verbose)'{-v,--verbose}'[use verbose output]' \
-                        '--color=:colorization option:(auto always never)' \
-                        '--vers[yank version]' \
+                        '--index=[specify registry index to yank from]:registry index' \
+                        '--token=[specify API token to use when authenticating]:token' \
+                        '*: :_guard "^-*" "crate"'
                         ;;
+                *)
+                    # allow plugins to define their own functions
+                    if ! _call_function ret _cargo-${words[1]}; then
+                        # fallback on default completion for unknown commands
+                        _default && ret=0
+                    fi
+                    (( ! ret ))
+                ;;
             esac
             ;;
     esac
 }
 
+_cargo_unstable_flags() {
+    local flags
+    flags=( help ${${${(M)${(f)"$(_call_program flags cargo -Z help)"}:#*--*}/ #-- #/:}##*-Z } )
+    _describe -t flags 'unstable flag' flags
+}
+
+_cargo_installed_crates() {
+    local expl
+    _description crates expl 'crate'
+    compadd "$@" "$expl[@]" - ${${${(f)"$(cargo install --list)"}:# *}%% *}
+}
+
 _cargo_cmds() {
     local -a commands
-    # This uses Parameter Expansion Flags, which is an Zsh built-in features.
+    # This uses Parameter Expansion Flags, which are a built-in Zsh feature.
     # See more: http://zsh.sourceforge.net/Doc/Release/Expansion.html#Parameter-Expansion-Flags
     # and       http://zsh.sourceforge.net/Doc/Release/Expansion.html#Parameter-Expansion
     #
@@ -433,29 +347,22 @@ _cargo_cmds() {
     # Then it replaces those spaces between item and description with a `:`
     #
     # [1]: https://github.com/zsh-users/zsh-completions/blob/master/zsh-completions-howto.org#patterns
-    commands=( ${${${(M)"${(f)$(cargo --list)}":#    *}/ ##/}/ ##/:} )
-    _describe 'command' commands
+    commands=( ${${${(M)"${(f)$(_call_program commands cargo --list)}":#    *}/ ##/}/ ##/:} )
+    _describe -t commands 'command' commands
 }
 
 
 #FIXME: Disabled until fixed
 #gets package names from the manifest file
-_get_package_names() {
-    :
-}
-
-#TODO:see if it makes sense to have 'locate-project' to have non-json output.
-#strips package name from json stuff
-_locate_manifest() {
-    local manifest=$(cargo locate-project 2>/dev/null)
-    regexp-replace manifest '\{"root":"|"\}' ''
-    echo "$manifest"
+_cargo_package_names() {
+    _message -e packages package
 }
 
 # Extracts the values of "name" from the array given in $1 and shows them as
 # command line options for completion
-_get_names_from_array() {
-    local manifest=$(_locate_manifest)
+_cargo_names_from_array() {
+    # strip json from the path
+    local manifest=${${${"$(cargo locate-project)"}%\"\}}##*\"}
     if [[ -z $manifest ]]; then
         return 0
     fi
@@ -488,25 +395,13 @@ _get_names_from_array() {
 }
 
 #Gets the test names from the manifest file
-_test_names() {
-    _get_names_from_array "test"
+_cargo_test_names() {
+    _cargo_names_from_array "test"
 }
 
 #Gets the bench names from the manifest file
-_benchmark_names() {
-    _get_names_from_array "bench"
+_cargo_benchmark_names() {
+    _cargo_names_from_array "bench"
 }
 
-# These flags are mutually exclusive specifiers for the scope of a command; as
-# they are used in multiple places without change, they are expanded into the
-# appropriate command's `_arguments` where appropriate.
-set command_scope_spec
-command_scope_spec=(
-    '(--bin --example --test --lib)--bench=[benchmark name]: :_benchmark_names'
-    '(--bench --bin --test --lib)--example=[example name]'
-    '(--bench --example --test --lib)--bin=[binary name]'
-    '(--bench --bin --example --test)--lib=[library name]'
-    '(--bench --bin --example --lib)--test=[test name]'
-)
-
 _cargo