Along with starting to support ternary expressions, this commit also
slightly changes SyntaxParsingContext APIs as follows:
1. Previously, makeNode() only supports node creation by using the nodes
from the underlying syntax token array; this commit allows it to use the nodes from
the pending syntax list as well.
2. This commit strictly limits that the pending syntax list should never
contain token syntax node.
3. The node kind test shouldn't include unknown kinds. They are noisy.
This commit also adds ArrayExpr and DictionaryExpr to the libSyntax nodes
family. Also, it refactors the original parser code for these two
expressions to better fit to the design of SyntaxParsingContext.
This commit has also fixed two crashers.
This commit teaches parser to parse two libSyntax nodes: FunctionCallArgument and
FunctionCallArgumentList. Along with the change, some libSyntax parsing infrastructure changes
as well: (1) parser doesn't directly insert token into the buffer for libSyntax node creation;
instead, when creating a simple libSyntax node like integer literal expression, parser should indicate the location of the last token in the node; (2) implicit libSyntax nodes like empty
statement list must contain a source location indicating where the implicit nodes should appear
(immediately before the token at the given location).
* Re-apply "libSyntax: Ensure round-trip printing when we build syntax tree from parser incrementally. (#12709)"
* Re-apply "libSyntax: Root parsing context should hold a reference to the current token in the parser, NFC."
* Re-apply "libSyntax: avoid copying token text when lexing token syntax nodes, NFC. (#12723)"
* Actually fix the container-overflow issue.
