`swift run --repl` fails to properly load dependencies

Is it reproducible with SwiftPM command-line tools: swift build, swift test, swift package etc?

• Confirmed reproduction steps with SwiftPM CLI. The description text must include reproduction steps with either of command-line SwiftPM commands, swift build, swift test, swift package etc.

Description

This is a re-write of https://github.com/swiftlang/swift/issues/90687, because I’ve been told the package manager is a better location for the bug.

Setup: A package that has a target (e.g. Dest) depending on non-Swift target(s) (e.g. Dep1 and Dep2, tested with C, ObjC), and whose target(s) do not contain a module.modulemap.

Issue: Running swift run --repl gives a REPL in which Dest cannot be imported (we get a “missing required module” error, for the modules Dep1 and Dep2, other dependencies work fine).

Expected behavior

The import should work.

Actual behavior

We get the error missing required modules: 'CMacroExports', 'CNSTaskHelptender'.

Steps to reproduce

1. git clone https://github.com/xcode-actions/swift-process-invocation.git
2. cd swift-process-invocation
3. swift run --repl
4. Once in the REPL (if you can get there; there is another issue that can prevent getting there, but relaunching should do the trick), try to import ProcessInvocation.

Swift Package Manager version/commit hash

Swift Package Manager - Swift 6.4.0-dev (Xcode 27.0 beta 3 (27A5218g))

Swift & OS version (output of swift --version ; uname -a)

swift-driver version: 1.168.4 Apple Swift version 6.4 (swiftlang-6.4.0.25.4 clang-2100.3.25.1) Target: arm64-apple-macosx27.0.0 Darwin Frizlabs-MacBook-Pro-Beta-Mojo.local 27.0.0 Darwin Kernel Version 27.0.0: Mon Jun 29 21:26:19 PDT 2026; root:xnu-13432.0.50.501.3~1/RELEASE_ARM64_T6031 arm64