Tya Diagnostic Codes

Every Tya diagnostic carries a stable code of the form TYA-Xnnnn:

• X is E for errors and W for warnings.
• nnnn is a zero-padded four-digit number.

Ranges are pre-allocated by stage so future migrations have room:

| Range | Stage | |-----------------|----------| | E0001–E0099 | lexer | | E0100–E0299 | parser | | E0300–E0599 | checker | | E0600–E0799 | codegen | | E0800–E0899 | runner | | E0900–E0999 | fmt | | W1000+ | warnings |

v0.29 ships the checker codes below. Lexer, parser, codegen, runner, and fmt errors will be migrated in later releases.

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TYA-E0301 — Shadowed binding

A new binding (for-loop variable, catch binding, match-pattern binding, or function-local introduction) reuses a name that is visible in a strictly enclosing scope.

count = 0
for count in [1, 2, 3]   # TYA-E0301: count shadows outer count
  print count

Fix: rename the inner binding, or prefix it with _ to mark it as intentional (_count).

TYA-E0302 — Unused import

A module is imported but no expression in the file references it.

import string            # TYA-E0302: string is imported but never used
print "hi"

Fix: remove the import, or reference the module somewhere in the file.

TYA-E0303 — Unused argument

A function parameter is never read in the body.

greet = value -> "hello"  # TYA-E0303: value is unused
print greet(1)

Fix: rename the parameter to _, or prefix it with _ (e.g. _value) to mark it intentional.

TYA-E0304 — Unused private definition

A top-level binding whose name starts with _ is never referenced elsewhere in the file. Names starting with _ are private to the file by convention; declaring one and never using it is treated as dead code.

_helper = 42              # TYA-E0304: _helper is never referenced
print "hi"

Fix: remove the definition, or reference it elsewhere in the file.

TYA-E0305 — Duplicate parameter

A function declares the same parameter name more than once.

f = x, x -> x             # TYA-E0305: duplicate parameter x

Fix: rename one of the parameters.

TYA-E0306 — Duplicate binding in pattern

A match pattern binds the same name in more than one position.

match ["a", "b"]
  case [name, name]       # TYA-E0306: name is bound twice
    print name

Fix: rename one of the bindings, or compare with an equality check in a guard once guards land.