Compilation Policies

A compilation policy selects behavior when code is lowered for an output. Different outputs can select different policies for the same source.

Source syntax

POLICY CHECK_BOUNDS
{
  TEST_ASSERT(index < count);
}
ELSE
{
  use_unchecked_index(@index index);
}

POLICY accepts ASSERT_ENABLED, CHECK_BOUNDS, CHECK_OVERFLOW, or UNIMPLEMENTED_PANICS, followed by a block and an optional ELSE block. Both alternatives undergo source semantic analysis; lowering selects one. STATIC_IF discards the unselected source branch before semantic generation.

Policy	Enabled behavior
ASSERT_ENABLED	Evaluate ASSERT and diagnose a false condition. Disabled assertions omit condition evaluation.
CHECK_BOUNDS	Check array indexing and array element-address bounds. Disabling checks leaves the validity requirement in force.
CHECK_OVERFLOW	Check assumed-in-range arithmetic (+!, -!, *!, /! and corresponding shifts/rotations); violations panic.
UNIMPLEMENTED_PANICS	A permitted UNIMPLEMENTED panics when reached. When disabled, a lowering-reachable statement fails compilation.

Explicit checked arithmetic such as +? throws ARITHMETIC_OVERFLOW independently of policy. TEST_ASSERT and TEST_EXPECT also remain active independently of assertion policy. See Arithmetic Operators and Failure Statements.

Output configuration

Boolean overrides appear under an output's policies mapping in qxcbuild.yml:

outputs:
  app/tests:
    target: native
    type: unit_test_suite
    test_modules: [tests]
    build_type: Release
    policies:
      policy_assert_enabled: true
      policy_check_bounds: true
      policy_check_overflow: true
      policy_unimplemented_panics: false

The target native and module tests must be configured in the same bundle. Unknown or repeated policy names are rejected.

Effective build type	Assertions, bounds, overflow checks	Unimplemented panics
Development, Debug, DebugOpt, DebugCompact, DebugCompactOpt	Enabled	Enabled
Quick, Compact, CompactOpt	Disabled	Enabled
Release, ReleaseDbgSym	Disabled	Disabled

Build type names ignore ASCII case and underscores. The default target build type is Development. An output can override it; for LLVM, the effective LLVM build_type determines policy defaults. Explicit policy entries override these defaults. Constant evaluation enables all four policies independently of output overrides.

unimplemented_compiles is a separate target-level Boolean, defaulting to true. Setting it to false rejects UNIMPLEMENTED during code generation, before output policy selection. See Build Configuration.