FEATURE: Key Semantics

Field	Value
Version	20260814 V1
Description	Enforces TOML key uniqueness and scalar-to-table definition rules.
Depends On	FEATURE-Key-Forms.md, FEATURE-Lexical-Numbers.md, FEATURE-Lexical-Datetime.md
Provides	key-definition validation
Consumes	TOML key paths, parser value model

Behavior

The parser records direct key definitions and implicitly created tables. It rejects duplicate keys, attempts to redefine equivalent bare and quoted keys, invalid key/value boundaries, and attempts to extend scalar values or otherwise closed structures as tables. Valid out-of-order dotted-key definitions remain accepted where TOML 1.0.0 permits them.

Programmatic Acceptance

Requires: executable=go; scope=test
Requires: executable=sh; scope=test

=== AC key-semantics-valid ===
Intent: The implementation passes the authoritative valid TOML key and specification conformance slices.
Suite: scoped

import os import subprocess import sys

result = subprocess.run( ["sh", "sources/stage_test.sh", "valid/key/*"], capture_output=True, text=True, env={**os.environ, "TOML_TEST_VERSION": "v2.2.0"}, ) print(result.stdout) print(result.stderr, file=sys.stderr) assert result.returncode == 0 === END AC key-semantics-valid ===

=== AC key-semantics-invalid ===
Intent: The implementation rejects duplicate and structurally invalid key definitions in the authoritative suite.
Suite: scoped

import os import subprocess import sys

result = subprocess.run( ["sh", "sources/stage_test.sh", "invalid/key/*"], capture_output=True, text=True, env={**os.environ, "TOML_TEST_VERSION": "v2.2.0"}, ) print(result.stdout) print(result.stderr, file=sys.stderr) assert result.returncode == 0 === END AC key-semantics-invalid ===

=== AC key-semantics-boundary ===
Intent: The implementation rejects invalid key/value boundaries in the authoritative specification suite.
Suite: scoped

import os import subprocess import sys

result = subprocess.run( ["sh", "sources/stage_test.sh", "invalid/spec-1.0.0/*"], capture_output=True, text=True, env={**os.environ, "TOML_TEST_VERSION": "v2.2.0"}, ) print(result.stdout) print(result.stderr, file=sys.stderr) assert result.returncode == 0 === END AC key-semantics-boundary ===

User Acceptance

None.

Guardrails

Equivalent key spellings cannot define the same key more than once.
A scalar value cannot later become a table or parent of a table.