Selection Ranges
Expand and shrink the selection by syntax (textDocument/selectionRange): each step grows the selection to the next enclosing construct — an expression, a statement with its semicolon, a declaration, a block — and also stops at what only the text shows, such as the inside of a pair of brackets, the text of a string literal or a comment. A file served in read-only mode, without a compiled AST, gets the text-only steps.
Syntax Ranges
Steps that follow the structure of the code, from the name under the cursor outward.
Nested expressions
Selection grows from the name under the cursor through each enclosing expression and statement
Statements and declarations
A statement or declaration is selected with the semicolon that ends it, after the part before it
A local variable steps from its declarator to the declaration statement. A member, a global or a function declaration gains its semicolon the same way; a template's declaration gains it before its template head joins.
Argument and parameter lists
The arguments of a call and the parameters of a function are selected without their parentheses before with them
Template argument and parameter lists
Template arguments and template parameters are selected inside their angle brackets before with them
Macro arguments
A name or expression written in a macro argument is selected where it is written, then the argument list and the whole invocation
Code a macro's replacement spells around the argument has no place in the file of its own: the steps go from the argument straight to the invocation.
Lambdas
A lambda's capture list, parameter list and body are steps of their own on the way to the whole lambda
Blocks and their contents
The statements of a block, the members of a class and the declarations of a namespace are selected without their braces before with them
A cursor on a blank line inside a block starts from the block's contents.
Function signatures
A function's name is selected with its signature before the whole declaration
The signature runs from the return type, or from the name of a constructor, through the parameters and what the declaration adds after them, such as const noexcept, a trailing return type, override or a requires clause.
Switch cases
A case label is selected with the statements it leads before the whole switch body
Documented declarations
A declaration is selected with the comment documenting it, from inside either one
Inside a block comment over several lines, the line under the cursor comes first, without the * it begins with.
Text Ranges
Steps that only the text shows: the inside of a literal's quotes, the text of a comment, the line of a directive.
String and character literals
The text of a string or character literal is selected without its quotes before with them
An encoding prefix, a raw string's delimiter and a user-defined suffix stay outside the text.
Comments
A comment's text is selected without its markers, then the comment, then the run of comment lines it belongs to
Preprocessor directives
A directive is selected as a whole line, after the header name it includes or the brackets of its macro body
Conditional Compilation
Steps through the code of #if blocks, the branches the preprocessor skipped included.
Conditional blocks
The lines of a conditional's branch and the whole #if through #endif are selected after the code inside them
A branch the preprocessor skipped gets the same steps, so its code can be selected as a whole.