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forbidden-declarations ​

Built-in rule: @codepol/plugin/forbidden-declarations

Reports configured declaration categories in JavaScript and TypeScript files using a TypeScript AST walk. This rule is report-only and is intended for teams that want to ban specific declaration forms such as class, interface, var, or import bindings.

When to use ​

  • Teams that want to ban entire declaration categories instead of only checking names.
  • Policies that need syntax-precise bans such as var, let, abstract class, or function*.
  • Codebases that still want no-interface as a separate fixable migration rule.

Configuration ​

Add the rule under [[rules]] and set any combination of args.symbols, args.bindings, and args.syntax.

Symbol categories ​

Supported args.symbols values:

  • namespace
  • class
  • interface
  • type
  • function
  • method
  • field
  • const
  • variable
  • parameter
  • enum
  • enumMember

variable applies to local let and var bindings only. It does not include imports or catch bindings.

Binding categories ​

Supported args.bindings values:

  • import for default, named, and namespace imports
  • catch for catch clause bindings
  • function-expression-name for inner names such as const x = function y() {}

Syntax categories ​

Supported args.syntax values:

  • var
  • let
  • abstract-class
  • generator-function

If both a broad category and a narrower syntax category match the same declaration, the rule emits a single diagnostic and uses the narrower syntax label.

Example ​

toml
[[plugins]]
id = "@codepol/plugin"
source = { kind = "builtin" }

[targets.app]
language = "typescript"
files = ["src/**/*.ts", "src/**/*.tsx"]

[[rules]]
ruleId = "@codepol/plugin/forbidden-declarations"
targets = ["app"]
args.symbols = ["class", "interface", "type", "enum"]
args.bindings = ["import"]
args.syntax = ["var"]

Reporting ​

Diagnostics use the format Forbidden declaration '<name>' (<label>).

  • Primary diagnostics highlight the banned keyword when the grammar has one (for example interface, class, type, function, enum, namespace, import, catch, const, let, var). That keeps squiggles on the keyword (for example only interface on an interface declaration), not across the whole body block.
  • Forms without a dedicated keyword use the name span only: method and field names, parameter and enum-member identifiers, and inner names on function expressions.
  • abstract class syntax bans highlight the abstract keyword; function* generator syntax bans highlight function through *.
  • Import bindings in the same statement share the single import keyword span. Multiple var/let bindings in one list each report with the same var/let keyword span.
  • When both a broad symbol category and a narrower syntax category match, the narrower syntax label is used and the span follows that syntax rule (for example abstract for abstract-class).
  • Anonymous default class and function exports are reported as default.

Current coverage ​

This v1 rule supports the declaration categories listed above for typescript, tsx, javascript, and jsx targets. It does not promise exhaustive TypeScript declaration coverage for constructors, accessors, class expressions, named class-expression names, type parameters, or overload signatures.

See also ​