[SR-4654] Struct extension implicitly imported from framework

[swift-ci]

Previous ID	SR-4654
Radar	None
Original Reporter	rermolov (JIRA User)
Type	Bug
Status	Resolved
Resolution	Duplicate

Environment

Apple Swift version 3.1 (swiftlang-802.0.51 clang-802.0.41)

Additional Detail from JIRA

Votes	1
Component/s
Labels	Bug
Assignee	None
Priority	Medium

md5: 5abb5d6469bc94cf525cf75ec7dd1249

duplicates:

• [SR-3908] Extension methods visible without importing module in a file #46493

Issue Description:

Struct extension from framework is accessible in file even if framework is not imported.

Example

Module A:

extension Date {
  public var someField: Int64 {
    return 123
  }
}

File1 from app:

import A
// do other stuff

File2 from app:

// no import A
Date().someField // compiles without errors

Expected behavior

Struct extensions should not be available without explicit framework import, like classes.

In general cases it is not a big deal, but it becomes a problem when you have module B with same extension, because in that case compilation fails with

ambiguous use of 'someField'

and you can't solve this issue by importing only one framework.