Can't build success with xcode toolchains swift 4.0.3 release

[JackLSH2016]

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What did you do?

ℹ I want to build with xcode toolchains swift 4.0.3 release

What did you expect to happen?

ℹpass build

What happened instead?

ℹ /Users/admin/Desktop/Work/wawameiyan的副本 2/Pods/Charts/Source/Charts/Filters/DataApproximator+N.swift:116:37: Value of type 'EnumeratedSequence<[CGPoint]>' has no member 'compactMap'

Charts Environment

3.1.1
Charts version/Branch/Commit Number:
**Xcode version:**xcode version is 9.3 but with xcode swift 4.0.3 release toolchains build
**Swift version:**Swift4.1
Platform(s) running Charts:
macOS version running Xcode:

Demo Project

ℹ Please link to or upload a project we can download that reproduces the issue.

[liuxuan30]

it's already swift 4.1. So don't use swift 4.0.3