[mperice]

Motivation

Go to definition on the name of a method declaration (def foo) returns nothing. On a class or module name (class Foo) it returns the declaration itself, which editors rely on: when the only definition is the one under the cursor, VS Code runs its alternative command, Go to References by default. So Cmd/Ctrl+click on a class name shows its usages, but on a method name it shows "No definition found", and finding a method's usages from its declaration needs a separate shortcut.

Implementation

• Requests::Definition accepts Prism::DefNode as a target, but only when the cursor is on the method's name (name_loc). The def keyword, parameters and body still return nothing, handled in position_outside_target? like the other targets that use name_loc.
• Listeners::Definition#on_def_node_enter returns a LocationLink to the method itself, with target_range covering the whole declaration and target_selection_range covering the name. It is skipped on typed: true or higher, as for method calls on self, because Sorbet handles method definitions there.

One thing to watch: with DefNode among the located node types, a cursor inside a method body that previously matched no target now locates the enclosing DefNode first. position_outside_target? then discards it, so those positions still return nothing. A test covers this.

Automated Tests

Added four tests to test/requests/definition_expectations_test.rb:

• Instance method name.
• Singleton method name (def self.bar).
• Positions inside a declaration but outside its name: the keyword, a parameter and the body.
• typed: true files, where nothing is returned.

The first two fail without the change. RuboCop and srb tc pass.

Manual Tests

1. Run this branch of the Ruby LSP in VS Code and open a Ruby file with a method declaration.
2. Cmd/Ctrl+click the method's name on its def line, or put the cursor on it and press F12.
3. VS Code opens the references peek for the method. Before this change it showed "No definition found".
4. For comparison, Cmd/Ctrl+click a class name in class Foo, which already behaves this way.

[mperice]

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