Strange as it sounds, we parse
@foo public
in item position as a decl that has a hanging attribute and access
control modifier. We need to be able to stick... something in the
tree here so we don't just drop these tokens on the floor.
When the source code is invalid, this allows us to represent tokens that could not be used to form a valid syntax tree with more fidelity.
This commit does not start using GarbageNodes yet, it just sets everything up for them.
In the future, we only want to attach a source presence to tokens, not to nodes. All concreate nodes which are missing can be represented by creating the node and marking all tokens as missing, but if a syntax node carries a child, that has a base kind (like `Decl`), we can’t decide which concrete node to instantiate. Introduce `MissingDecl` etc. node for this purpose.
rdar://97908258
rdar://97775360
Creating a new CodeBlockItem meant that when doing an edit in the error
nodes, the prefix gets reused and thus the code is parsed as invalid
although it is not.
Swift syntax APIs lack an abstract way of accessing children. The client has to
down-cast a syntax node to the leaf type to access any of its children. However,
some children are common among different syntax kinds, e.g.
DeclAttributeSyntax and DeclMembers. We should allow an abstract way to
access and modify them, so that clients can avoid logic duplication.
This patch adds a mechanism to define new traits and specify satisfied
traits in specific syntax nodes. A trait is a set of common children
and implemented in Swift as a protocol for syntax nodes to conform to.
As a proof-of-concept, we added two traits for now including DeclGroupSyntax
and BracedSyntax.
Resolves: SR-6931 and SR-6916
* Generate libSyntax API
This patch removes the hand-rolled libSyntax API and replaces it with an
API that's entirely automatically generated. This means the API is
guaranteed to be internally stylistically and functionally consistent.
