gen-c: lower the element type of a local array - #3449
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Closes #3448 var x : [4]GF16; -> GF16 x[4]; error: use of undeclared identifier 'GF16' The same element is `uint16_t` in a parameter (`uint16_t a[static 4]`) and in a struct field (`uint16_t f[4];`). Only the local path passed the t27 text through, because it gated on `is_primitive` -- and the note retiring that very gate sits two hundred lines below, on `param_type_to_c`: W583: this used to be gated on `is_primitive`, which lists only the integer scalars -- so `f32`, `f64`, `str`, `string` and `gf16` took the pass-through arm and reached C unmapped even after `type_to_c` learned them. Same sentence, same file, other position. Two more defects live in the same eight lines. `var x : []u8;` emitted `uint8_t x[];`, which is not a definition; and `var x : []const u8;` emitted `const u8* x`, because the qualifier lives INSIDE the element text and this path did not strip it. The first slice repair was wrong, and the corpus said so: rewriting every `[]T` local to a pointer broke `T x[] = { ... }`, which is legal C and takes its size from the initialiser list. +5 errors, nothing better, in the one file carrying the shape. `size.is_empty() && node.children.is_empty()` is that measurement kept as code. MEASURED, and this is the part that matters beyond this commit. CLANG'S DEFAULT -ferror-limit=20 HAS BEEN CENSORING EVERY TOTAL I HAVE PUBLISHED THIS SESSION. 141 files reach the limit. The corpus emits 15133 errors, not the 3849 reported. The per-file splits were sound, because they were counted per file; the totals were floors. this change 15133 -> 15126 3 files better, 0 worse #3447, re-measured 15188 -> 15133 published as 3849 -> 3825 The direction and the per-file conclusions stand; the magnitudes were understated. It surfaced because a repair that removes real errors showed a ZERO delta -- three files sitting at exactly 20 before and after. tools/backend_parity_table.py gains the fourth position. Its first probe there measured the wrong thing: `var x : T;` with no initialiser is declared by C and Rust and emitted by NEITHER Zig nor Verilog, so the table was reading their dead-code removal. Initialising from a parameter of the same type fixed it, and the self-check now covers all four positions. Four mutants, four dead. 14 seals refreshed in the same commit. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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Closes #3450 Refs #3448 One instrument had been censoring its own totals -- clang's default `-ferror-limit=20`, which made every C error count published for this repository a floor. The obvious next question is whether the others do the same, and nobody had asked. Planting 50 known errors per language: clang (default) 20 TRUNCATES clang (-ferror-limit=0) 50 complete rustc 50 complete zig 50 complete iverilog 50 complete (TWO diagnostic lines per error) yosys 1 ABORTS on the first error yosys is not capped, it stops. An error COUNT from it is 0 or 1 and means nothing; only its pass/fail is a measurement. THE FIXTURES WERE THE HARD PART, and two of the five were wrong in ways that read as findings about the compiler rather than about me: * the Zig fixture named its functions `f16` and `f32`, which SHADOW ZIG PRIMITIVES, so it failed with 2 errors of a different kind before reaching the undefined names -- indistinguishable from a cap; * the Verilog fixture used implicitly declared identifiers, which yosys treats as a WARNING, so it reported zero -- indistinguishable from silence. `--self-check` therefore requires each fixture to produce the expected KIND of diagnostic before its count is believed. WHAT IS NOT AFFECTED, measured rather than hoped: * acceptance counts. Clang's exit code is 1 with and without the limit on a failing file, and 0 on a clean one, so a count of FILES that compile cannot be censored by a per-file cap. Every `cc accepts N` figure stands. * the repository's gates. The only tool invoking `cc` is check_duplicate_agreement.py, and it reads `returncode`. * the Rust totals, since rustc reports completely. What was wrong is exactly the C error totals in my own reports: 3849 was 15188, 3825 was 15133, and after #3449 it is 15126. The tool DEGRADES rather than lying. A runner without zig or yosys checks the compilers it has and NAMES what it skipped; only a run with nothing available exits 2. That matters because the CI runner carries neither, and a gate that cannot run must say so rather than fail forever. Four controls: a planted truncation reddens it, a one-compiler PATH passes while naming four skips, an empty PATH exits 2, and a fixture that stops producing its error fails the self-check. Wired into Spec Guards, under a second. Co-authored-by: lab <lab@example.com> Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
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Closes #3448
The same element is lowered everywhere else:
uint16_t a[static 4]uint16_t f[4];GF16 x[4];W583, in a position its own repair never reached
The local path gated on
is_primitive. Two hundred lines below, onparam_type_to_c, sits the note retiring exactly that gate:Same sentence, same file, other position. Two more defects live in the same
eight lines:
var x : []u8;emitteduint8_t x[];(not a definition), andvar x : []const u8;emittedconst u8* x(the qualifier lives inside theelement text).
The first slice repair was wrong, and the corpus said so
Rewriting every
[]Tlocal to a pointer brokeT x[] = { … }, which islegal C and takes its size from the initialiser list: +5 errors, nothing
better, in the one file carrying the shape. The condition
size.is_empty() && node.children.is_empty()is that measurement kept as code,and a test holds it.
Every error total I published this session was a floor
This is the finding worth more than the fix.
Clang's default
-ferror-limit=20was censoring the aggregate. 141 filesreach the limit. The corpus emits 15133 errors, not the 3849 I have been
reporting.
The per-file splits were sound — they were counted per file — and the
directions and conclusions stand. The magnitudes were understated.
It surfaced only because a repair that removes real errors showed a zero
delta: three files sitting at exactly 20 before and after.
Three files improve here:
math/property_test_template46→43,nn/hslm79→76,numeric/gf16151→150. Zero files worse.The tool
tools/backend_parity_table.pygains the fourth position. Its first probethere measured the wrong thing:
var x : T;with no initialiser is declared byC and Rust and emitted by neither Zig nor Verilog, so the table was reading
their dead-code removal rather than their lowering. Initialising from a
parameter of the same type fixed it; the self-check now covers all four
positions.
Mutation
is_primitivegate restoredconststrip removedFull suite: 2615 passed, 0 failed. 14 seals refreshed in the same commit.