Experimental rules

New rules will be added into the experimental ruleset, which can be enabled by passing the --experimental flag to ktlint.

Block comment initial star alignment¶

Lines in a block comment which (exclusive the indentation) start with a * should have this * aligned with the * in the opening of the block comment.

Rule id: experimental:block-comment-initial-star-alignment

Discouraged comment location¶

Detect discouraged comment locations (no autocorrect).

Rule id: experimental:discouraged-comment-location

Unnecessary parenthesis before trailing lambda¶

An empty parentheses block before a lambda is redundant.

Ktlint Disallowed

some-string".count { it == '-' }

some-string".count() { it == '-' }

Rule id: experimental:unnecessary-parentheses-before-trailing-lambda

Function signature¶

Rewrites the function signature to a single line when possible (e.g. when not exceeding the max_line_length property) or a multiline signature otherwise. In case of function with a body expression, the body expression is placed on the same line as the function signature when not exceeding the max_line_length property. Optionally the function signature can be forced to be written as a multiline signature in case the function has more than a specified number of parameters (.editorconfig' propertyktlint_function_signature_wrapping_rule_always_with_minimum_parameters`)

Rule id: function-signature

Spacing¶

Fun keyword spacing¶

Consistent spacing after the fun keyword.

Rule id: experimental:fun-keyword-spacing

Function return type spacing¶

Consistent spacing around the function return type.

Rule id: experimental:function-return-type-spacing

Function start of body spacing¶

Consistent spacing before start of function body.

Rule id: experimental:function-start-of-body-spacing:

Function type reference spacing¶

Consistent spacing in the type reference before a function.

Rule id: experimental:function-type-reference-spacing

Modifier list spacing¶

Consistent spacing between modifiers in and after the last modifier in a modifier list.

Rule id: experimental:modifier-list-spacing

Nullable type spacing¶

No spaces in a nullable type.

Rule id: experimental:nullable-type-spacing

Parameter list spacing¶

Consistent spacing inside the parameter list.

Rule id: experimental:parameter-list-spacing

Spacing between function name and opening parenthesis¶

Consistent spacing between function name and opening parenthesis.

Rule id: experimental:spacing-between-function-name-and-opening-parenthesis

Type argument list spacing¶

Spacing before and after the angle brackets of a type argument list.

Rule id: experimental:type-argument-list-spacing

Type parameter list spacing¶

Spacing after a type parameter list in function and class declarations.

Rule id: experimental:type-parameter-list-spacing

Wrapping¶

Comment wrapping¶

A block comment should start and end on a line that does not contain any other element. A block comment should not be used as end of line comment.

Rule id: experimental:comment-wrapping

Kdoc wrapping¶

A KDoc comment should start and end on a line that does not contain any other element.

Rule id: experimental:kdoc-wrapping