[tomtourwe]

What

static Function<String,Integer> parser() { return Util::parse; } printed = Util ::parse,
which Kotlin types as a KFunction1, no java.util.function.Function (return type mismatch); a local
Function<String, Integer> f = Util::parse lost its declared type the same way. As an argument
Kotlin converts the reference itself, which is why that case compiled.

Now: Function<String, Int>(Util ::parse) for returned and assigned values, when the interface
has no wildcard type arguments; arguments are unchanged.
Test: TestJavaToKotlinCalls.staticReferenceReturnedAsFunction (output compiles with kotlinc).

How it was found

A mutation-testing run (PIT) over the lines that maddi's latest 100 commits changed listed the changed code no
existing test checks. Tests written for those lines, from what each commit says the code should do, exposed this
bug while writing tests for aa93b0e; the bug is older than that commit.

Tests

On devel 07b926b: the new test fails without the fix and passes with it.
With this fix and the nine others of this series applied together, every maddi test passes
(run on 7bc974b: 2,743 tests, 0 failures).

🤖 Generated with Claude Code

[bnaudts]

Thanks. Devel had already fixed this independently (the method-reference SAM constructor in KotlinExpressionPrinter.assigned()). So the fix itself isn't taken. Your test passes without it on devel, and it is kept as a regression test in 00e31a8, with you as author. Closing this PR.

The whole batch (#146–#155) passes the Kotlin, C#, printer, front-end, inspection and bytecode suites on JDK 26 and JDK 27. It goes into devel with the next merge of the ws/maddi-bug branch.

🤖 Generated with Claude Code