False CORE::try/catch ambiguity warnings break Try::Tiny consumers

[fglock]

Summary

PerlOnJava emits false Ambiguous call resolved as CORE::try() and CORE::catch() warnings when compiling modules that import try/catch from Try::Tiny. These warnings make otherwise passing CPAN tests fail under Test::NoWarnings.

Reproduction

The issue was observed while testing TBX::Min version 0.08 in CPAN random run 20260921-124328-13959 at PerlOnJava commit d8e4fd417.

The distribution's standard Perl suite passes all 162 tests. Under PerlOnJava, both the JVM backend and interpreter backend reproduce the warnings with the dependency set used by the run. A minimal load reproducer is:

use DateTime::Format::Strptime;

The warnings include:

Ambiguous call resolved as CORE::try(), qualify as such or use &
Ambiguous call resolved as CORE::catch(), qualify as such or use &

They originate in Try::Tiny consumers including DateTime::Format::Strptime, Module::Implementation, DateTime, and DateTime::TimeZone. PerlOnJava reports these warnings even though the code imports and calls the Try::Tiny functions; standard Perl does not report them for the same suite.

CPAN impact

TBX::Min reports 8 failed test programs out of 10 and 8 failed subtests out of 162. In each affected test program, the only failure is the Test::NoWarnings check; functional assertions pass.

The distribution contains no XS or native code, so no native reverse-dependency analysis is applicable.

Expected behavior

PerlOnJava should match standard Perl warning behavior: importing try and catch from Try::Tiny should not produce false ambiguity warnings merely because Perl has a CORE::try construct.

Environment

• PerlOnJava backends: JVM and interpreter
• Standard Perl oracle: Perl 5.42.2 on macOS
• Affected dependency: DateTime::Format::Strptime 1.80
• CPAN distribution: TBX::Min 0.08

[fglock]

Additional CPAN impact: Dist::Zilla 6.039 fails because the same false CORE::try / CORE::catch ambiguity warnings are captured as command output.

In CPAN random run 20260924-115230-59978, standard Perl 5.42.2 passed the unmodified Dist::Zilla suite completely (57 files, 504 tests). PerlOnJava's JVM acceptance run failed 38 of 531 subtests across 5 files. The t/commands/listdeps.t failures are directly attributable to the warnings: its expected dependency-list output contains extra diagnostics from Try::Tiny consumers, including Class::MOP, Moose, Module::Implementation, Class::Load, Log::Dispatchouli, and Dist::Zilla::Dist::Builder.

The focused interpreter run reproduces the same warnings before the first listdeps subtest completes. This confirms that the issue affects both execution backends and now blocks a central CPAN release-management tool, not only test suites that use Test::NoWarnings.

Focused reproducer with Dist::Zilla's normal test prerequisites:

prove -v t/commands/listdeps.t

Expected: only dependency-list output is captured. Actual on PerlOnJava: Ambiguous call resolved as CORE::try() and CORE::catch() diagnostics are added to that output.