Added go completion script. Taken from /misc/zsh/go

plugins/go/go.plugin.zsh

+# install in /etc/zsh/zshrc or your personal .zshrc
+
+# gc
+prefixes=(5 6 8)
+for p in $prefixes; do
+	compctl -g "*.${p}" ${p}l
+	compctl -g "*.go" ${p}g
+done
+
+# standard go tools
+compctl -g "*.go" gofmt
+
+# gccgo
+compctl -g "*.go" gccgo
+
+# go tool
+__go_tool_complete() {
+  typeset -a commands build_flags
+  commands+=(
+    'build[compile packages and dependencies]'
+    'clean[remove object files]'
+    'doc[run godoc on package sources]'
+    'fix[run go tool fix on packages]'
+    'fmt[run gofmt on package sources]'
+    'get[download and install packages and dependencies]'
+    'help[display help]'
+    'install[compile and install packages and dependencies]'
+    'list[list packages]'
+    'run[compile and run Go program]'
+    'test[test packages]'
+    'tool[run specified go tool]'
+    'version[print Go version]'
+    'vet[run go tool vet on packages]'
+  )
+  if (( CURRENT == 2 )); then
+    # explain go commands
+    _values 'go tool commands' ${commands[@]}
+    return
+  fi
+  build_flags=(
+    '-a[force reinstallation of packages that are already up-to-date]'
+    '-n[print the commands but do not run them]'
+    "-p[number of parallel builds]:number"
+    '-x[print the commands]'
+    "-work[print temporary directory name and keep it]"
+    "-gcflags[flags for 5g/6g/8g]:flags"
+    "-ldflags[flags for 5l/6l/8l]:flags"
+    "-gccgoflags[flags for gccgo]:flags"
+  )
+  __go_list() {
+      local expl importpaths
+      declare -a importpaths
+      importpaths=($(go list ${words[$CURRENT]}... 2>/dev/null))
+      _wanted importpaths expl 'import paths' compadd "$@" - "${importpaths[@]}"
+  }
+  case ${words[2]} in
+  clean|doc)
+      _arguments -s -w : '*:importpaths:__go_list'
+      ;;
+  fix|fmt|list|vet)
+      _alternative ':importpaths:__go_list' ':files:_path_files -g "*.go"'
+      ;;
+  install)
+      _arguments -s -w : ${build_flags[@]} \
+        "-v[show package names]" \
+	'*:importpaths:__go_list'
+      ;;
+  get)
+      _arguments -s -w : \
+        ${build_flags[@]}
+      ;;
+  build)
+      _arguments -s -w : \
+        ${build_flags[@]} \
+        "-v[show package names]" \
+        "-o[output file]:file:_files" \
+        "*:args:{ _alternative ':importpaths:__go_list' ':files:_path_files -g \"*.go\"' }"
+      ;;
+  test)
+      _arguments -s -w : \
+        ${build_flags[@]} \
+        "-c[do not run, compile the test binary]" \
+        "-i[do not run, install dependencies]" \
+        "-v[print test output]" \
+        "-x[print the commands]" \
+        "-short[use short mode]" \
+        "-parallel[number of parallel tests]:number" \
+        "-cpu[values of GOMAXPROCS to use]:number list" \
+        "-run[run tests and examples matching regexp]:regexp" \
+        "-bench[run benchmarks matching regexp]:regexp" \
+        "-benchtime[run each benchmark during n seconds]:duration" \
+        "-timeout[kill test after that duration]:duration" \
+        "-cpuprofile[write CPU profile to file]:file:_files" \
+        "-memprofile[write heap profile to file]:file:_files" \
+        "-memprofilerate[set heap profiling rate]:number" \
+        "*:args:{ _alternative ':importpaths:__go_list' ':files:_path_files -g \"*.go\"' }"
+      ;;
+  help)
+      _values "${commands[@]}" \
+        'gopath[GOPATH environment variable]' \
+        'importpath[description of import paths]' \
+        'remote[remote import path syntax]' \
+        'testflag[description of testing flags]' \
+        'testfunc[description of testing functions]'
+      ;;
+  run)
+      _arguments -s -w : \
+          ${build_flags[@]} \
+          '*:file:_path_files -g "*.go"'
+      ;;
+  tool)
+      if (( CURRENT == 3 )); then
+          _values "go tool" $(go tool)
+          return
+      fi
+      case ${words[3]} in
+      [568]g)
+          _arguments -s -w : \
+              '-I[search for packages in DIR]:includes:_path_files -/' \
+              '-L[show full path in file:line prints]' \
+              '-S[print the assembly language]' \
+              '-V[print the compiler version]' \
+              '-e[no limit on number of errors printed]' \
+              '-h[panic on an error]' \
+              '-l[disable inlining]' \
+              '-m[print optimization decisions]' \
+              '-o[file specify output file]:file' \
+              '-p[assumed import path for this code]:importpath' \
+              '-u[disable package unsafe]' \
+              "*:file:_files -g '*.go'"
+          ;;
+      [568]l)
+          local O=${words[3]%l}
+          _arguments -s -w : \
+              '-o[file specify output file]:file' \
+              '-L[search for packages in DIR]:includes:_path_files -/' \
+              "*:file:_files -g '*.[ao$O]'"
+          ;;
+      dist)
+          _values "dist tool" banner bootstrap clean env install version
+          ;;
+      *)
+          # use files by default
+          _files
+          ;;
+      esac
+      ;;
+  esac
+}
+
+compdef __go_tool_complete go