go/src/go/parser/resolver_test.go

// TestResolution checks that identifiers are resolved to the declarations
// annotated in the source, by comparing the positions of the resulting
// Ident.Obj.Decl to positions marked in the source via special comments.
//
// In the test source, any comment prefixed with '=' or '@' (or both) marks the
// previous token position as the declaration ('=') or a use ('@') of an
// identifier. The text following '=' and '@' in the comment string is the
// label to use for the location.  Declaration labels must be unique within the
// file, and use labels must refer to an existing declaration label. It's OK
// for a comment to denote both the declaration and use of a label (e.g.
// '=@foo'). Leading and trailing whitespace is ignored. Any comment not
// beginning with '=' or '@' is ignored.
func TestResolution(t *testing.T) { … }

// declsFromParser walks the file and collects the map associating an
// identifier position with its declaration position.
func declsFromParser(file *ast.File) map[token.Pos]token.Pos { … }

// declsFromComments looks at comments annotating uses and declarations, and
// maps each identifier use to its corresponding declaration. See the
// description of these annotations in the documentation for TestResolution.
func declsFromComments(handle *token.File, src []byte) map[token.Pos]token.Pos { … }

// positionMarkers extracts named positions from the source denoted by comments
// prefixed with '=' (declarations) and '@' (uses): for example '@foo' or
// '=@bar'. It returns a map of name->position for declarations, and
// name->position(s) for uses.
func positionMarkers(handle *token.File, src []byte) (decls map[string]token.Pos, uses map[string][]token.Pos) { … }

func annotatedObj(lit string) (name string, decl, use bool) { … }