Diagnose reserved BrightScript builtins used as values#1697
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Diagnose reserved BrightScript builtins used as values#1697
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Adds a new diagnostic (`reservedBuiltinUsedAsValue`, code 1147) that
fires when a reserved call-only BrightScript builtin appears in any
non-call position. These builtins compile cleanly today in the
brighterscript parser but produce a device compile error
(typically `Syntax Error. Builtin function call expected`, hex &h9d,
or `Syntax Error` &h02 depending on the builtin).
Builtins covered (all device-verified):
- box, createobject, getglobalaa
- getlastruncompileerror, getlastrunruntimeerror
- objfun, pos, run, tab, type
The check fires from `primary()` after an identifier match, gated on
`peek().kind !== LeftParen` so canonical call sites (e.g. `type(x)`,
`Box(1)`, `CreateObject("roSGNode", "Node")`) remain clean. Property
access (`m.type = 1`) and AA-literal keys (`{ type: 1 }`) are not
affected because they use different parse paths. BrighterScript's
`type Name = ...` statement is also unaffected.
Adds 38 tests:
- per-builtin RHS-read flag + canonical-call no-flag pairs (16)
- per-builtin parameter-name 1045 regression tests (10)
- ObjFun/type-specific edge cases: passed-as-arg, property access,
AA-keys, type-statement, case-insensitivity (12)
`Eval` is intentionally excluded from this set. Its compile error
(&h90 RSG 1.2 deprecation) is a different concern and merits a
separate, more pointed diagnostic.
eval is a call-only builtin like the others here — referencing it as a value (`x = eval`, etc.) is a device compile error.
TwitchBronBron
requested changes
May 4, 2026
Rename CallOnlyBuiltins to UnreferencableBuiltins and move the value-read check from the parser into BrsFileValidator so plugin-injected AST nodes are also caught. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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Summary
Adds a new diagnostic (
reservedBuiltinUsedAsValue, code 1147) that fires when a reserved call-only BrightScript builtin appears in any non-call position. These builtins parse cleanly today but produce a device compile error (Syntax Error. Builtin function call expected, &h9d, or genericSyntax Error&h02 for some).Builtins covered:
box,createobject,eval,getglobalaagetlastruncompileerror,getlastrunruntimeerrorobjfun,pos,run,tab,typeBefore / after
x = ObjFun'ObjFun' is a reserved builtin and can only be used as a function call (e.g. 'ObjFun(...)')x = typex = evalprint foo(Box, 2)ObjFun(),type(123),Box(1),eval(...)etc.m.type = 1,{ type: 1 }type Name = ...(BrighterScript type alias)Implementation
CallOnlyBuiltinsset in src/lexer/TokenKind.ts, keyed by lowercased text.reservedBuiltinUsedAsValue(code 1147) in src/DiagnosticMessages.ts.primary()at src/parser/Parser.ts that fires whentext.toLowerCase()is inCallOnlyBuiltinsandpeek().kind !== LeftParen.Why these specific builtins
Each was tested on a Roku device by writing the various forms (
x = Foo,Foo(...),m.Foo = 1,{ Foo: 1 },function f(Foo)) and observing whether each form was a device compile error, runtime error, or successful execution. The 11 names above are the set where non-call usage is a hard compile error on device.evalis included because referencing it as a value has always been a compile error across firmware versions; its separate deprecation/removal lifecycle for call sites is handled in #1698.Test plan
npm test— 2806 passing, 0 failingnpm run lint— cleantype statementregression test updated to expect the new diagnostic forreturn type🤖 Generated with Claude Code