All Diagnostics

Complete reference of every diagnostic code. For an introduction to how diagnostics work and how to configure them, see the Diagnostics guide.

Warning severity

Code	Description
deprecated	Usage of @deprecated symbols
discard-returns	Ignoring @nodiscard return values
type-mismatch	Argument type vs @param mismatch
return-mismatch	Return type vs @return mismatch
field-type-mismatch	Field assignment vs @field type mismatch
assign-type-mismatch	Reassignment vs @type mismatch
generic-constraint-mismatch	Generic argument doesn't satisfy class constraint
missing-parameter	Missing required function arguments
redundant-parameter	Extra function arguments
missing-return-value	Return with fewer values than @return
redundant-return-value	Return with more values than @return
grouped-return-mismatch	Return values don't match any tuple-union @return case
missing-return	Function missing return statement
undefined-global	Reference to unresolved global name
undefined-field	Accessing nonexistent field on @class
need-check-nil	Field/method access on possibly-nil value (off by default)
access-private	Accessing @field private from outside
access-protected	Accessing @field protected from outside hierarchy (also _-prefixed fields when implicit_protected_prefix is enabled)
duplicate-index	Duplicate keys in table constructors
redundant-value	Extra values in assignments
unbalanced-assignments	More variables than values in assignments
missing-fields	Missing required fields when constructing @class tables
undefined-doc-class	Undefined class name in @class Foo: Parent
undefined-doc-name	Undefined type name in annotations
undefined-doc-param	@param name not matching function parameters
duplicate-doc-param	Duplicate @param annotations
duplicate-doc-field	Duplicate @field annotations
duplicate-doc-alias	Duplicate @alias declarations
doc-field-no-class	@field on a non-@class table
doc-func-no-function	Function-level annotation (@param, @return, etc.) not attached to a function definition
circle-doc-class	Circular @class inheritance chains
malformed-annotation	Unknown or incomplete ---@ annotations
multi-return-projection	returns<F> discards extra return values from F
builds-field-not-self	@builds-field method uses @return ClassName instead of @return self
unknown-diag-code	Unknown code in @diagnostic directives
duplicate-constructor	Multiple @constructor on a single class
constructor-return	@constructor with return other than @return self
count-down-loop	For-loop step direction doesn't match start/end
wrong-flavor-api	API not available in all declared flavors
redundant-class-generic	Method redeclares class-level @generic

Hint severity

Code	Description
return-self-class-name	Method uses @return ClassName instead of @return self
unused-local	Unreferenced local variables
unused-function	Unused function definitions
unused-vararg	Function declares ... but never uses it (off by default)
redefined-local	Same-scope local variable redefinition
create-global	Implicit global creation
inject-field	Setting undeclared fields on @class tables
duplicate-set-field	Setting an already-set field on @class tables
unreachable-code	Code after return
code-after-break	Code after break
incomplete-signature-doc	Partial @param/@return annotations (off by default)
empty-block	Empty control flow body
redundant-return	Bare return at end of function
trailing-space	Line ends with whitespace
not-precedence	not x <cmp> y is (not x) <cmp> y
implicit-nil-return	Bare return in function with optional @return (off by default)
unknown-param-type	Parameter type can't be inferred (off by default)
unknown-return-type	Return value has no resolvable type (off by default)
unknown-local-type	Local assignment has unknown type (off by default)
unknown-field-type	Field assignment has unknown type (off by default)

LuaLS compatibility aliases

Alias	Maps to
invisible	access-private, access-protected
param-type-mismatch	type-mismatch
return-type-mismatch	return-mismatch