go type_error ai_generated true

cannot range over func() (value of type func())

ID: go/cannot-range-over-function

Also available as: JSON · Markdown · 中文
90%Fix Rate
85%Confidence
1Evidence
2023-06-20First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
Go 1.18 active — — —
Go 1.19 active — — —
Go 1.20 active — — —
Go 1.21 active — — —
Go 1.22 active — — —

Root Cause

Trying to use range on a function type instead of a slice, map, string, channel, or array.

generic

中文

尝试对函数类型使用 range 迭代，而不是对切片、映射、字符串、通道或数组使用。

Official Documentation

https://go.dev/ref/spec#For_range

Workarounds

  1. 95% success Ensure the function returns a slice or another iterable type, then range over the return value 
    Ensure the function returns a slice or another iterable type, then range over the return value
  2. 85% success Use a channel if you want to iterate over values produced by a function (goroutine + channel pattern) 
    Use a channel if you want to iterate over values produced by a function (goroutine + channel pattern)

中文步骤

  1. 确保函数返回一个切片或其他可迭代类型，然后对返回值进行 range 迭代
  2. 如果想迭代函数产生的值，使用通道（goroutine + 通道模式）

Dead Ends

Common approaches that don't work:

  1. 70% fail

    If the function returns a single value that is not iterable, the same error occurs on the return type.

  2. 95% fail

    Go does not allow range on interface{} either; it must be a concrete iterable type.