Enum DefaultScopeError 

pub enum DefaultScopeError {
    DuplicateDefaultClocking(String),
    DuplicateDefaultDisable(String),
    UnresolvedDefaultClockingTarget(String),
    DefaultClockingTargetNotAClockingBlock(String),
}

Task 8 (sva T8, docs/superpowers/plans/2026-10-03-sva.md): LRM 1800-2023 14.12’s default clocking and 16.15’s default disable iff – the scoping half only (which single declaration, if any, covers a given scope): resolving the lexical-nesting/override rules both clauses state almost verbatim (“valid only within the scope containing the declaration … as well as any nested module[s] … It does not include instantiated modules” – 14.12; “provides a default … to all concurrent assertions in the scope and subscopes … the default extends to any nested module … However, if a nested module … has a [its own] declaration, then that … overrides any default … from outside” – 16.15). The resolution-rule half of 16.15 (composing this against an assertion’s own explicit disable iff clause, rules (a)/(b)/(c)) is T27’s job, consuming default_disable_of’s result – not reimplemented here.

Why a syntax walk, not a sv-lang semantic accessor

The vendored C++ slang already has exactly this query (slang::ast::Compilation::getDefaultClocking/getDefaultDisable, include/slang/ast/Compilation.h) – but, unlike 16.13.3/16.16’s clock flow (T7) or 16.14.6’s procedural clock inference (T6), sv-lang 0.1.9 exposes no FFI binding to either one at all (confirmed by grepping the installed crate’s own generated ast.rs/sys surface for default_clocking/default_disable and finding nothing – not assumed). Per the same plan-wide posture T6/T7 already apply (“wrap what’s exposed, reimplement only what genuinely is not”), this task reconstructs 14.12/16.15 directly from the syntax tree, exactly as the plan’s own Task 8 “Files”/“Steps” text asks: walking module_or_generate_item_declaration’s default clocking clocking_identifier ;/inline [default] clocking ... endclocking/ default disable iff expr ; forms (DefaultClockingReferenceSyntax/ ClockingDeclarationSyntax/DefaultDisableDeclarationSyntax).

Lexical nesting via Symbol::parent(), confirmed live

14.12/16.15’s “nested declaration inherits; mere instantiation does not” distinction sounds like it needs a second, syntax-ancestry walk independent of the elaborated instance tree – but sv_lang::Symbol:: parent() (slang_symbol_parent_scope) turns out to already encode exactly that distinction, confirmed live against both shapes before writing this function (not assumed from the plan’s prose): for a module m2 declared as a nested declaration textually inside m1 and instantiated there, m2’s elaborated InstanceBody::parent() is m1’s own InstanceBody; for the identical textual declaration of m2 hoisted to the top level and merely instantiated inside m1, m2’s InstanceBody::parent() is the design’s CompilationUnit root – never m1 – even though m2 is instantiated in exactly the same place in both cases. I.e. parent() already walks the lexical declaration-site scope chain, not the elaborated instantiation hierarchy, which is exactly what both clauses need told apart. The same holds for a GenerateBlock symbol (its parent() is its lexically enclosing module/generate scope). So [each_lexical_scope] below climbs Symbol::parent() alone, never a second, independent Node::parent() syntax-ancestry walk.

Variants

DuplicateDefaultClocking(String)

14.12: “Specifying a default clocking more than once in the same module, interface, program, or checker shall result in a compiler error.” Carries the offending scope’s name.

DuplicateDefaultDisable(String)

16.15: “More than one default disable iff declaration within the same module, interface, program declaration, or generate block shall be an error.” Carries the offending scope’s name.

UnresolvedDefaultClockingTarget(String)

A default clocking clocking_identifier; reference whose name does not resolve to any member of the scope it was declared in. Defensive – 14.12’s own “clocking_identifier shall be the name of a clocking block” is a semantic rule slang itself already enforces on a fatal-error-free Design, so this should be unreachable, but a loud named error is still required over a silent None/panic.

DefaultClockingTargetNotAClockingBlock(String)

As above, but the name resolved to a real member that is not itself a clocking block.

Trait Implementations

impl Debug for DefaultScopeError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.