[nahime0]

Problem

Autoloaded class files were lexed with the entry file's source identity 0, and the resolver of their own includes rewound the identity counter (Span::reset_source_ids). Two physically different files therefore produced equal spans for statements at the same line and column, and every span-keyed checker result leaked between them: throw_access_sites, builtin_call_types, loop_storage_types, the call-type memo, the local binding decisions.

Concrete miscompile (the Ivory repro, PSR-4 App\ -> src/): src/Fixed.lfc:9:9 initializes a readonly property, src/Counter.lfc:9:9 is a plain $this->total = ... write. Counter::add() got Fixed's readonly guard and the program died with

Fatal error: Uncaught Error: Cannot modify readonly property App\Fixed::$value in .../main.lfc:9

instead of printing 2. Ivory hit this as soon as it had a second class with a readonly property assigned in a constructor (6 unrelated tests broke). The same collision also made two autoloaded files with a retype at the same position fail with Cannot re-bind $x here, and checker errors inside an autoloaded file printed a bare error[7:16] that read as a position in the entry file.

Fix

The span identity approach comes from #1921 by @JGamboa; this PR ports that part as a focused change.

1. fix(autoload): autoload::load_autoloaded_file lexes each file with Span::fresh_source_id() and resolves its includes through a new resolver::resolve_collecting_includes_continuing, which does not rewind the counter. Span::reset_source_ids moved from the shared resolver body to the root entry resolve_collecting_includes_with_defines, so it runs once per compile. Every file a compile loads now has its own identity, so equal coordinates in two files are distinct map keys.
2. fix(diagnostics): each loader registers the path behind the identity it hands out (Span::register_source_path, per thread like the counter), and print_error / print_warning name Span::source_path() first. The span wins over a file tag because the pipeline tags every lowering, export and --emit-ir refusal with the entry filename (found by Greptile); the tag is kept only for spans with no registered source, which is every entry-file span. A checker or lowering error inside an included or autoloaded file now prints error[<path>:line:col].

Difference from #1921

#1921 also registers the entry file, so every positioned diagnostic becomes error[file:line:col]. That is a CLI-wide format change beyond #1445, so I left it out: the entry file is never registered and its diagnostics keep error[line:col]. It stays compatible with landing that change later. The other parts of #1921 (autoload prelude probe, monotonic method variadics, checker cost indexes, schema error spans) are untouched here and remain #1921's.

Tests

• tests/codegen/spl/autoload_span_identity.rs (new):
  • the exact three-file LFC repro through the CLI, expects 2 (fails on main with the readonly error above);
  • a PHP variant through the in-process multi-file harness with the plain write autoloaded first, checking that the readonly class still rejects its own second write;
  • two autoloaded files with retypes at the same position compile and run (0s / 1t; main: Cannot re-bind $x here, the autoload part of Give Span a file identity so cross-file same-position collisions stop being compile errors #778);
  • --check on an autoloaded file with an undefined class names src/Broken.lfc:7:16 (main: error[7:16]).
• tests/codegen/include_paths.rs: a checker error inside a required file names lib.php:3:12 (main: error[3:12]), and a lowering refusal inside a required file (--emit-ir) names lib.php:6:5 (main: error[main.php:6:5]).
• Unit tests: span::tests::registered_source_paths_name_the_file_of_their_spans, errors::report::tests::diagnostic_file_falls_back_to_the_span_source.

I reproduced the failing behaviour of the integration fixtures on main with an existing build; the new code itself is validated by CI only (no local cargo runs on this shared machine).

Not addressed

• The runtime location of a thrown error (Throwable::getFile(), the in <file>:<line> suffix of the uncaught report) is still the per-module entry script path for code that came from an included or autoloaded file (lower_throwable_get_file). With this fix the bogus readonly error no longer happens, but a genuine error raised in a class file still names main.lfc. That needs a per-throwable file slot in the runtime and is left for a follow-up.
• The Cannot re-bind message and its cli-reference.md section still say a position carries no file; after this PR neither of the causes they list (two files, a file required twice) can trigger it. Left for a follow-up so the message and docs change together.

Fixes #1445. Overlaps #1921.

[greptile-apps]

Confidence Score: 5/5

[Medium impact] The PR appears safe to merge; the previous filename issue is fixed and no new actionable issues were found.

Summary

This PR gives included and autoloaded files distinct span identities and records their paths for diagnostics.

• Autoloaded class files keep their checker results separate.
• Diagnostics from loaded files name the file they came from.

_{Reviews (2) · Last reviewed commit: "fix(diagnostics): let the span's source ..." · Reviewed by Greptile}