Swift: dbscheme generator

This patch introduces the basic infrastructure of the code generation
suite and the `dbscheme` generator.

Notice that the checked in `schema.yml` should reflect swift 5.6 but
might need some tweaking.

Closes https://github.com/github/codeql-c-team/issues/979

swift/README.md

@@ -4,6 +4,32 @@ The Swift codeql package is an experimental and unsupported work in progress.
 
 ## Usage
 
-Run `bazel run //swift:create-extractor-pack`, which will install `swift/extractor-pack`.
+Run
+
+```bash
+bazel run //swift:create-extractor-pack
+```
+
+which will install `swift/extractor-pack`.
+
 Using `--search-path=swift/extractor-pack` will then pick up the Swift extractor. You can also use
 `--search-path=swift`, as the extractor pack is mentioned in `swift/.codeqlmanifest.json`.
+
+Notice you can run `bazel run :create-extractor-pack` if you already are in the `swift` directory.
+
+## Code generation
+
+Make sure to install the [pip requirements](./codegen/requirements.txt) via
+
+```bash
+python3 -m pip install -r codegen/requirements.txt
+```
+
+Run
+
+```bash
+bazel run //swift/codegen
+```
+
+to update generated files. This can be shortened to
+`bazel run codegen` if you are in the `swift` directory.

swift/codegen/BUILD.bazel

@@ -0,0 +1,8 @@
+py_binary(
+    name = "codegen",
+    srcs = glob(["**/*.py"]),
+    data = glob(["**/*.mustache"]) + [
+        "schema.yml",
+        "prefix.dbscheme",
+    ],
+)

swift/codegen/codegen.py

@@ -0,0 +1,7 @@
+#!/usr/bin/env python3
+
+from lib import generator
+import dbschemegen
+
+if __name__ == "__main__":
+    generator.run(dbschemegen.generate)

swift/codegen/dbschemegen.py

@@ -0,0 +1,76 @@
+#!/usr/bin/env python3
+
+import inflection
+
+from lib.renderer import Renderer
+from lib.dbscheme import *
+from lib import paths, schema, generator
+
+log = logging.getLogger(__name__)
+
+
+def dbtype(typename):
+    if typename[0].isupper():
+        return "@" + inflection.underscore(typename)
+    return typename
+
+
+def cls_to_dbscheme(cls: schema.Class):
+    if cls.derived:
+        yield DbUnion(dbtype(cls.name), (dbtype(c) for c in cls.derived))
+    if not cls.derived or any(f.is_single() for f in cls.fields):
+        binding = not cls.derived
+        keyset = DbKeySet(["id"]) if cls.derived else None
+        yield DbTable(
+            keyset=keyset,
+            name=inflection.tableize(cls.name),
+            columns=[
+                        DbColumn("id", type=dbtype(cls.name), binding=binding),
+                    ] + [
+                        DbColumn(f.name, dbtype(f.type)) for f in cls.fields if f.is_single()
+                    ]
+        )
+    for f in cls.fields:
+        if f.is_optional():
+            yield DbTable(
+                keyset=DbKeySet(["id"]),
+                name=inflection.tableize(f"{cls.name}_{f.name}"),
+                columns=[
+                    DbColumn("id", type=dbtype(cls.name)),
+                    DbColumn(f.name, dbtype(f.type)),
+                ],
+            )
+        elif f.is_repeated():
+            yield DbTable(
+                keyset=DbKeySet(["id", "index"]),
+                name=inflection.tableize(f"{cls.name}_{f.name}"),
+                columns=[
+                    DbColumn("id", type=dbtype(cls.name)),
+                    DbColumn("index", type="int"),
+                    DbColumn(inflection.singularize(f.name), dbtype(f.type)),
+                ]
+            )
+
+
+def generate(opts):
+    input = opts.schema.resolve()
+    out = opts.dbscheme.resolve()
+    renderer = Renderer(opts.check)
+
+    with open(input) as src:
+        data = schema.load(src)
+
+    declarations = [d for cls in data.classes.values() for d in cls_to_dbscheme(cls)]
+
+    includes = []
+    for inc in data.includes:
+        inc = input.parent / inc
+        with open(inc) as inclusion:
+            includes.append({"src": inc.relative_to(paths.swift_dir), "data": inclusion.read()})
+    renderer.render("dbscheme", out, includes=includes, src=input.relative_to(paths.swift_dir),
+                    declarations=declarations)
+    return renderer.written
+
+
+if __name__ == "__main__":
+    generator.run(generate, tags=["schema", "dbscheme"])

swift/codegen/lib/dbscheme.py

@@ -0,0 +1,85 @@
+import logging
+import re
+from dataclasses import dataclass
+from typing import ClassVar, List
+
+log = logging.getLogger(__name__)
+
+dbscheme_keywords = {"case", "boolean", "int", "string", "type"}
+
+
+@dataclass
+class DbColumn:
+    schema_name: str
+    type: str
+    binding: bool = False
+    first: bool = False
+
+    def name(self):
+        if self.schema_name in dbscheme_keywords:
+            return self.schema_name + "_"
+        return self.schema_name
+
+    def lhstype(self):
+        if self.type[0] == "@":
+            return "unique int" if self.binding else "int"
+        return self.type
+
+    def rhstype(self):
+        if self.type[0] == "@" and self.binding:
+            return self.type
+        return self.type + " ref"
+
+
+@dataclass
+class DbKeySetId:
+    id: str
+    first: bool = False
+
+
+@dataclass
+class DbKeySet:
+    ids: List[DbKeySetId]
+
+    def __post_init__(self):
+        assert self.ids
+        self.ids = [DbKeySetId(x) for x in self.ids]
+        self.ids[0].first = True
+
+
+class DbDecl:
+    is_table = False
+    is_union = False
+
+
+@dataclass
+class DbTable(DbDecl):
+    is_table: ClassVar = True
+
+    name: str
+    columns: List[DbColumn]
+    keyset: DbKeySet = None
+
+    def __post_init__(self):
+        if self.columns:
+            self.columns[0].first = True
+
+
+@dataclass
+class DbUnionCase:
+    type: str
+    first: bool = False
+
+
+@dataclass
+class DbUnion(DbDecl):
+    is_union: ClassVar = True
+
+    lhs: str
+    rhs: List[DbUnionCase]
+
+    def __post_init__(self):
+        assert self.rhs
+        self.rhs = [DbUnionCase(x) for x in self.rhs]
+        self.rhs.sort(key=lambda c: c.type)
+        self.rhs[0].first = True

swift/codegen/lib/generator.py

@@ -0,0 +1,55 @@
+import argparse
+import collections
+import logging
+import pathlib
+import sys
+
+from . import paths
+
+options = collections.defaultdict(list)
+
+
+class Option:
+    def __init__(self, *args, tags=None, **kwargs):
+        tags = tags or []
+        self.args = args
+        self.kwargs = kwargs
+        if tags:
+            for t in tags:
+                options[t].append(self)
+        else:
+            options["*"].append(self)
+
+    def add_to(self, parser: argparse.ArgumentParser):
+        parser.add_argument(*self.args, **self.kwargs)
+
+
+Option("--check", "-c", action="store_true")
+Option("--verbose", "-v", action="store_true")
+Option("--schema", tags=["schema"], type=pathlib.Path, default=paths.swift_dir / "codegen/schema.yml")
+Option("--dbscheme", tags=["dbscheme"], type=pathlib.Path, default=paths.swift_dir / "ql/lib/swift.dbscheme")
+
+
+def _parse(*tags):
+    parser = argparse.ArgumentParser()
+    if not tags:
+        opts = [o for os in options.values() for o in os]
+    else:
+        opts = options["*"]
+        for t in tags:
+            opts.extend(options[t])
+    for opt in opts:
+        opt.add_to(parser)
+    ret = parser.parse_args()
+    log_level = logging.DEBUG if ret.verbose else logging.INFO
+    logging.basicConfig(format="{levelname} {message}", style='{', level=log_level)
+    return ret
+
+
+def run(*generate, tags=()):
+    opts = _parse(*tags)
+    done_something = False
+    for g in generate:
+        if g(opts):
+            done_something = True
+    sys.exit(1 if opts.check and done_something else 0)

swift/codegen/lib/paths.py

@@ -0,0 +1,15 @@
+import pathlib
+import sys
+import os
+
+try:
+    _workspace_dir = pathlib.Path(os.environ['BUILD_WORKSPACE_DIRECTORY'])
+    swift_dir = _workspace_dir / 'swift'
+    lib_dir = swift_dir / 'codegen' / 'lib'
+except KeyError:
+    _this_file = pathlib.Path(__file__).resolve()
+    swift_dir = _this_file.parents[2]
+    lib_dir = _this_file.parent
+
+
+exe_file = pathlib.Path(sys.argv[0]).resolve()

swift/codegen/lib/renderer.py

@@ -0,0 +1,59 @@
+import hashlib
+import logging
+
+import pystache
+
+from . import paths
+
+log = logging.getLogger(__name__)
+
+
+def md5(data):
+    return hashlib.md5(data).digest()
+
+
+class Renderer:
+    def __init__(self, check=False):
+        self.r = pystache.Renderer(search_dirs=str(paths.lib_dir / "templates"), escape=lambda u: u)
+        self.generator = paths.exe_file.relative_to(paths.swift_dir)
+        self.check = check
+        self.written = set()
+        self.skipped = set()
+        self.erased = set()
+
+    @property
+    def done_something(self):
+        return bool(self.written or self.erased)
+
+    @property
+    def rendered(self):
+        return self.written | self.skipped
+
+    def render(self, name, output, **data):
+        mnemonic, _, _ = name.lower().partition(".")
+        output.parent.mkdir(parents=True, exist_ok=True)
+        data["generator"] = self.generator
+        data = self.r.render_name(name, data)
+        if output.is_file():
+            with open(output, "rb") as file:
+                if md5(data.encode()) == md5(file.read()):
+                    log.debug(f"skipped {output.name}")
+                    self.skipped.add(output)
+                    return
+        if self.check:
+            log.error(f"would have generated {mnemonic} {output.name}")
+        else:
+            with open(output, "w") as out:
+                out.write(data)
+            log.info(f"generated {mnemonic} {output.name}")
+        self.written.add(output)
+
+    def cleanup(self, existing):
+        for f in existing - self.written - self.skipped:
+            if f.is_file():
+                if self.check:
+                    log.error(f"would have removed {f.name}")
+                else:
+                    f.unlink()
+                    log.info(f"removed {f.name}")
+                self.erased.add(f)

swift/codegen/lib/schema.py

@@ -0,0 +1,98 @@
+import pathlib
+from dataclasses import dataclass, field
+from enum import Enum, auto
+from typing import List, Set, Dict
+import re
+
+import yaml
+
+
+class Cardinality(Enum):
+    ONE = auto()
+    OPTIONAL = auto()
+    MANY = auto()
+
+
+@dataclass
+class Field:
+    name: str
+    type: str
+    cardinality: Cardinality = Cardinality.ONE
+
+    def is_single(self):
+        return self.cardinality == Cardinality.ONE
+
+    def is_optional(self):
+        return self.cardinality == Cardinality.OPTIONAL
+
+    def is_repeated(self):
+        return self.cardinality == Cardinality.MANY
+
+
+@dataclass
+class Class:
+    name: str
+    bases: Set[str] = field(default_factory=set)
+    derived: Set[str] = field(default_factory=set)
+    fields: List[Field] = field(default_factory=list)
+    dir: pathlib.Path = pathlib.Path()
+
+
+@dataclass
+class Schema:
+    classes: Dict[str, Class]
+    includes: Set[str] = field(default_factory=set)
+
+
+def _parse_field(name, type):
+    if type.endswith("*"):
+        cardinality = Cardinality.MANY
+        type = type[:-1]
+    elif type.endswith("?"):
+        cardinality = Cardinality.OPTIONAL
+        type = type[:-1]
+    else:
+        cardinality = Cardinality.ONE
+    return Field(name, type, cardinality)
+
+
+root_class_name = "Element"
+
+
+class DirSelector:
+    def __init__(self, dir_to_patterns):
+        self.selector = [(re.compile(p), pathlib.Path(d)) for d, p in dir_to_patterns]
+        self.selector.append((re.compile(""), pathlib.Path()))
+
+    def get(self, name):
+        return next(d for p, d in self.selector if p.search(name))
+
+
+def load(file):
+    data = yaml.load(file, Loader=yaml.SafeLoader)
+    grouper = DirSelector(data.get("_directories", {}).items())
+    ret = Schema(classes={cls: Class(cls, dir=grouper.get(cls)) for cls in data if not cls.startswith("_")},
+                 includes=set(data.get("_includes", [])))
+    assert root_class_name not in ret.classes
+    ret.classes[root_class_name] = Class(root_class_name)
+    for name, info in data.items():
+        if name.startswith("_"):
+            continue
+        assert name[0].isupper()
+        cls = ret.classes[name]
+        for k, v in info.items():
+            if not k.startswith("_"):
+                cls.fields.append(_parse_field(k, v))
+            elif k == "_extends":
+                if not isinstance(v, list):
+                    v = [v]
+                for base in v:
+                    cls.bases.add(base)
+                    ret.classes[base].derived.add(name)
+            elif k == "_dir":
+                cls.dir = pathlib.Path(v)
+        if not cls.bases:
+            cls.bases.add(root_class_name)
+            ret.classes[root_class_name].derived.add(name)
+
+    return ret

swift/codegen/lib/templates/dbscheme.mustache

@@ -0,0 +1,25 @@
+// generated by {{generator}}
+{{#includes}}
+
+// from {{src}}
+{{data}}
+{{/includes}}
+
+// from {{src}}
+{{#declarations}}
+
+{{#is_union}}
+{{lhs}} =
+{{#rhs}}
+{{#first}}  {{/first}}{{^first}}| {{/first}}{{type}}
+{{/rhs}};
+{{/is_union}}
+{{#is_table}}
+{{#keyset}}
+#keyset[{{#ids}}{{^first}}, {{/first}}{{id}}{{/ids}}]
+{{/keyset}}
+{{name}}({{#columns}}{{^first}},{{/first}}
+  {{lhstype}} {{name}}: {{rhstype}}{{/columns}}
+);
+{{/is_table}}
+{{/declarations}}

swift/codegen/prefix.dbscheme

@@ -0,0 +1,6 @@
+/**
+ * The source location of the snapshot.
+ */
+sourceLocationPrefix(
+  string prefix: string ref
+);

swift/codegen/requirements.txt

@@ -0,0 +1,3 @@
+pystache
+pyyaml
+inflection

swift/codegen/schema.yml

@@ -0,0 +1,997 @@
+# add dbscheme files to be added verbatim
+_includes:
+  - prefix.dbscheme
+
+# organize generated class files in subdirectories according to these regexp rules
+# a class can override this specifying `_dir`
+_directories:
+  decl: Decl$|Context$
+  pattern: Pattern$
+  type: Type$
+  typerepr: TypeRepr$
+  expr: Expr$
+  stmt: Stmt$
+
+File:
+  name: string
+
+IterableDeclContext:
+  members: Decl*
+
+Locatable:
+  location: Location
+
+Location:
+  file: File
+  begin_line: int
+  begin_column: int
+  end_line: int
+  end_column: int
+
+Type:
+  diagnostics_name: string
+  canonical_type: Type
+
+ExtensionDecl:
+  _extends:
+    - GenericContext
+    - IterableDeclContext
+    - Decl
+
+NominalTypeDecl:
+  _extends:
+    - IterableDeclContext
+    - GenericTypeDecl
+  type: Type
+
+AstNode:
+  _extends: Locatable
+
+ConditionElement:
+  _extends: Locatable
+  boolean: Expr?
+  pattern: Pattern?
+  initializer: Expr?
+  _dir: stmt
+
+AnyFunctionType:
+  _extends: Type
+  result: Type
+  param_types: Type*
+  param_labels: string*
+
+AnyGenericType:
+  _extends: Type
+  parent: Type?
+  declaration: Decl
+
+AnyMetatypeType:
+  _extends: Type
+
+BuiltinType:
+  _extends: Type
+
+DependentMemberType:
+  _extends: Type
+
+DynamicSelfType:
+  _extends: Type
+
+ErrorType:
+  _extends: Type
+
+InOutType:
+  _extends: Type
+
+LValueType:
+  _extends: Type
+  object_type: Type
+
+ModuleType:
+  _extends: Type
+
+PlaceholderType:
+  _extends: Type
+
+ProtocolCompositionType:
+  _extends: Type
+
+ExistentialType:
+  _extends: Type
+
+ReferenceStorageType:
+  _extends: Type
+
+SilBlockStorageType:
+  _extends: Type
+
+SilBoxType:
+  _extends: Type
+
+SilFunctionType:
+  _extends: Type
+
+SilTokenType:
+  _extends: Type
+
+SubstitutableType:
+  _extends: Type
+
+SugarType:
+  _extends: Type
+
+TupleType:
+  _extends: Type
+
+TypeVariableType:
+  _extends: Type
+
+UnknownType:
+  _extends: Type
+  name: string
+
+UnresolvedType:
+  _extends: Type
+
+ClassDecl:
+  _extends: NominalTypeDecl
+
+EnumDecl:
+  _extends: NominalTypeDecl
+
+ProtocolDecl:
+  _extends: NominalTypeDecl
+
+StructDecl:
+  _extends: NominalTypeDecl
+
+Decl:
+  _extends: AstNode
+
+Expr:
+  _extends: AstNode
+  type: Type?
+
+Pattern:
+  _extends: AstNode
+
+Stmt:
+  _extends: AstNode
+
+TypeRepr:
+  _extends: AstNode
+
+FunctionType:
+  _extends: AnyFunctionType
+
+GenericFunctionType:
+  _extends: AnyFunctionType
+  generic_params: GenericTypeParamType*
+
+NominalOrBoundGenericNominalType:
+  _extends: AnyGenericType
+
+UnboundGenericType:
+  _extends: AnyGenericType
+
+ExistentialMetatypeType:
+  _extends: AnyMetatypeType
+
+MetatypeType:
+  _extends: AnyMetatypeType
+
+AnyBuiltinIntegerType:
+  _extends: BuiltinType
+
+BuiltinBridgeObjectType:
+  _extends: BuiltinType
+
+BuiltinDefaultActorStorageType:
+  _extends: BuiltinType
+
+BuiltinExecutorType:
+  _extends: BuiltinType
+
+BuiltinFloatType:
+  _extends: BuiltinType
+
+BuiltinJobType:
+  _extends: BuiltinType
+
+BuiltinNativeObjectType:
+  _extends: BuiltinType
+
+BuiltinRawPointerType:
+  _extends: BuiltinType
+
+BuiltinRawUnsafeContinuationType:
+  _extends: BuiltinType
+
+BuiltinUnsafeValueBufferType:
+  _extends: BuiltinType
+
+BuiltinVectorType:
+  _extends: BuiltinType
+
+UnmanagedStorageType:
+  _extends: ReferenceStorageType
+
+UnownedStorageType:
+  _extends: ReferenceStorageType
+
+WeakStorageType:
+  _extends: ReferenceStorageType
+
+ArchetypeType:
+  _extends: SubstitutableType
+
+GenericTypeParamType:
+  _extends: SubstitutableType
+  name: string
+
+ParenType:
+  _extends: SugarType
+
+SyntaxSugarType:
+  _extends: SugarType
+
+TypeAliasType:
+  _extends: SugarType
+
+EnumCaseDecl:
+  _extends: Decl
+  elements: EnumElementDecl*
+
+IfConfigDecl:
+  _extends: Decl
+
+ImportDecl:
+  _extends: Decl
+
+MissingMemberDecl:
+  _extends: Decl
+
+OperatorDecl:
+  _extends: Decl
+
+PatternBindingDecl:
+  _extends: Decl
+  inits: Expr*
+  patterns: Pattern*
+
+PoundDiagnosticDecl:
+  _extends: Decl
+
+PrecedenceGroupDecl:
+  _extends: Decl
+
+TopLevelCodeDecl:
+  _extends: Decl
+  body: BraceStmt
+
+UnknownAstNode:
+  _extends:
+    - Decl
+    - Expr
+    - Pattern
+    - Stmt
+    - TypeRepr
+  name: string
+
+ValueDecl:
+  _extends: Decl
+  interface_type: Type
+
+AbstractClosureExpr:
+  _extends: Expr
+
+AnyTryExpr:
+  _extends: Expr
+  sub_expr: Expr
+
+AppliedPropertyWrapperExpr:
+  _extends: Expr
+
+Argument:
+  label: string
+  expr: Expr
+  _dir: expr
+
+ApplyExpr:
+  _extends: Expr
+  function: Expr
+  arguments: Argument*
+
+ArrowExpr:
+  _extends: Expr
+
+AssignExpr:
+  _extends: Expr
+  dest: Expr
+  src: Expr
+
+BindOptionalExpr:
+  _extends: Expr
+
+CaptureListExpr:
+  _extends: Expr
+
+CodeCompletionExpr:
+  _extends: Expr
+
+CollectionExpr:
+  _extends: Expr
+
+DeclRefExpr:
+  _extends: Expr
+  decl: Decl
+  replacement_types: Type*
+
+DefaultArgumentExpr:
+  _extends: Expr
+  param_decl: ParamDecl
+  param_index: int
+  caller_side_default: Expr?
+
+DiscardAssignmentExpr:
+  _extends: Expr
+
+DotSyntaxBaseIgnoredExpr:
+  _extends: Expr
+
+DynamicTypeExpr:
+  _extends: Expr
+
+EditorPlaceholderExpr:
+  _extends: Expr
+
+EnumIsCaseExpr:
+  _extends: Expr
+
+ErrorExpr:
+  _extends: Expr
+
+ExplicitCastExpr:
+  _extends: Expr
+  sub_expr: Expr
+
+ForceValueExpr:
+  _extends: Expr
+  sub_expr: Expr
+
+IdentityExpr:
+  _extends: Expr
+  sub_expr: Expr
+
+IfExpr:
+  _extends: Expr
+
+ImplicitConversionExpr:
+  _extends: Expr
+  sub_expr: Expr
+
+InOutExpr:
+  _extends: Expr
+  sub_expr: Expr
+
+KeyPathApplicationExpr:
+  _extends: Expr
+
+KeyPathDotExpr:
+  _extends: Expr
+
+KeyPathExpr:
+  _extends: Expr
+  parsed_root: Expr?
+  parsed_path: Expr?
+
+LazyInitializerExpr:
+  _extends: Expr
+
+LiteralExpr:
+  _extends: Expr
+
+LookupExpr:
+  _extends: Expr
+
+MakeTemporarilyEscapableExpr:
+  _extends: Expr
+
+ObjCSelectorExpr:
+  _extends: Expr
+
+OneWayExpr:
+  _extends: Expr
+
+OpaqueValueExpr:
+  _extends: Expr
+
+OpenExistentialExpr:
+  _extends: Expr
+
+OptionalEvaluationExpr:
+  _extends: Expr
+
+OtherConstructorDeclRefExpr:
+  _extends: Expr
+
+OverloadSetRefExpr:
+  _extends: Expr
+
+PropertyWrapperValuePlaceholderExpr:
+  _extends: Expr
+
+RebindSelfInConstructorExpr:
+  _extends: Expr
+
+SequenceExpr:
+  _extends: Expr
+
+SuperRefExpr:
+  _extends: Expr
+
+TapExpr:
+  _extends: Expr
+  sub_expr: Expr?
+  var: VarDecl
+  body: BraceStmt
+
+TupleElementExpr:
+  _extends: Expr
+
+TupleExpr:
+  _extends: Expr
+  elements: Expr*
+
+TypeExpr:
+  _extends: Expr
+  type_repr: UnknownAstNode?
+
+UnresolvedDeclRefExpr:
+  _extends: Expr
+
+UnresolvedDotExpr:
+  _extends: Expr
+
+UnresolvedMemberExpr:
+  _extends: Expr
+
+UnresolvedPatternExpr:
+  _extends: Expr
+
+UnresolvedSpecializeExpr:
+  _extends: Expr
+
+VarargExpansionExpr:
+  _extends: Expr
+  sub_expr: Expr
+
+AnyPattern:
+  _extends: Pattern
+
+BindingPattern:
+  _extends: Pattern
+  sub_pattern: Pattern
+
+BoolPattern:
+  _extends: Pattern
+  value: boolean
+
+EnumElementPattern:
+  _extends: Pattern
+  element: EnumElementDecl
+  sub_pattern: Pattern?
+
+ExprPattern:
+  _extends: Pattern
+  sub_expr: Expr
+
+IsPattern:
+  _extends: Pattern
+  cast_type_repr: TypeRepr
+  sub_pattern: Pattern?
+
+NamedPattern:
+  _extends: Pattern
+  name: string
+
+OptionalSomePattern:
+  _extends: Pattern
+  sub_pattern: Pattern
+
+ParenPattern:
+  _extends: Pattern
+  sub_pattern: Pattern
+
+TuplePattern:
+  _extends: Pattern
+  elements: Pattern*
+
+TypedPattern:
+  _extends: Pattern
+  sub_pattern: Pattern
+  type_repr: TypeRepr?
+
+BraceStmt:
+  _extends: Stmt
+  elements: AstNode*
+
+BreakStmt:
+  _extends: Stmt
+  target_name: string?
+  target: Stmt?
+
+CaseStmt:
+  _extends: Stmt
+  body: Stmt
+  labels: CaseLabelItem*
+  variables: VarDecl*
+
+CaseLabelItem:
+  _extends: AstNode
+  pattern: Pattern
+  guard: Expr?
+  _dir: stmt
+
+ContinueStmt:
+  _extends: Stmt
+  target_name: string?
+  target: Stmt?
+
+DeferStmt:
+  _extends: Stmt
+  body: BraceStmt
+
+FailStmt:
+  _extends: Stmt
+
+FallthroughStmt:
+  _extends: Stmt
+  fallthrough_source: CaseStmt
+  fallthrough_dest: CaseStmt
+
+LabeledStmt:
+  _extends: Stmt
+  label: string?
+
+PoundAssertStmt:
+  _extends: Stmt
+
+ReturnStmt:
+  _extends: Stmt
+  result: Expr?
+
+ThrowStmt:
+  _extends: Stmt
+  sub_expr: Expr
+
+YieldStmt:
+  _extends: Stmt
+
+BoundGenericType:
+  _extends: NominalOrBoundGenericNominalType
+
+NominalType:
+  _extends: NominalOrBoundGenericNominalType
+
+BuiltinIntegerLiteralType:
+  _extends: AnyBuiltinIntegerType
+
+BuiltinIntegerType:
+  _extends: AnyBuiltinIntegerType
+
+NestedArchetypeType:
+  _extends: ArchetypeType
+
+SequenceArchetypeType:
+  _extends: ArchetypeType
+
+OpaqueTypeArchetypeType:
+  _extends: ArchetypeType
+
+OpenedArchetypeType:
+  _extends: ArchetypeType
+
+PrimaryArchetypeType:
+  _extends: ArchetypeType
+  interface_type: GenericTypeParamType
+
+DictionaryType:
+  _extends: SyntaxSugarType
+
+UnarySyntaxSugarType:
+  _extends: SyntaxSugarType
+
+InfixOperatorDecl:
+  _extends: OperatorDecl
+
+PostfixOperatorDecl:
+  _extends: OperatorDecl
+
+PrefixOperatorDecl:
+  _extends: OperatorDecl
+
+AbstractFunctionDecl:
+  _extends:
+    - GenericContext
+    - ValueDecl
+  name: string
+  body: BraceStmt?
+  params: ParamDecl*
+
+AbstractStorageDecl:
+  _extends: ValueDecl
+
+EnumElementDecl:
+  _extends: ValueDecl
+  name: string
+  params: ParamDecl*
+
+TypeDecl:
+  _extends: ValueDecl
+  name: string
+
+AutoClosureExpr:
+  _extends: AbstractClosureExpr
+
+ClosureExpr:
+  _extends: AbstractClosureExpr
+  body: BraceStmt
+
+ForceTryExpr:
+  _extends: AnyTryExpr
+
+OptionalTryExpr:
+  _extends: AnyTryExpr
+
+TryExpr:
+  _extends: AnyTryExpr
+
+BinaryExpr:
+  _extends: ApplyExpr
+
+CallExpr:
+  _extends: ApplyExpr
+
+PostfixUnaryExpr:
+  _extends: ApplyExpr
+
+PrefixUnaryExpr:
+  _extends: ApplyExpr
+
+SelfApplyExpr:
+  _extends: ApplyExpr
+  base: Expr
+
+ArrayExpr:
+  _extends: CollectionExpr
+  elements: Expr*
+
+DictionaryExpr:
+  _extends: CollectionExpr
+  elements: Expr*
+
+CheckedCastExpr:
+  _extends: ExplicitCastExpr
+
+CoerceExpr:
+  _extends: ExplicitCastExpr
+
+AwaitExpr:
+  _extends: IdentityExpr
+
+DotSelfExpr:
+  _extends: IdentityExpr
+
+ParenExpr:
+  _extends: IdentityExpr
+
+UnresolvedMemberChainResultExpr:
+  _extends: IdentityExpr
+
+AnyHashableErasureExpr:
+  _extends: ImplicitConversionExpr
+
+ArchetypeToSuperExpr:
+  _extends: ImplicitConversionExpr
+
+ArrayToPointerExpr:
+  _extends: ImplicitConversionExpr
+
+BridgeFromObjCExpr:
+  _extends: ImplicitConversionExpr
+
+BridgeToObjCExpr:
+  _extends: ImplicitConversionExpr
+
+ClassMetatypeToObjectExpr:
+  _extends: ImplicitConversionExpr
+
+CollectionUpcastConversionExpr:
+  _extends: ImplicitConversionExpr
+
+ConditionalBridgeFromObjCExpr:
+  _extends: ImplicitConversionExpr
+
+CovariantFunctionConversionExpr:
+  _extends: ImplicitConversionExpr
+
+CovariantReturnConversionExpr:
+  _extends: ImplicitConversionExpr
+
+DerivedToBaseExpr:
+  _extends: ImplicitConversionExpr
+
+DestructureTupleExpr:
+  _extends: ImplicitConversionExpr
+
+DifferentiableFunctionExpr:
+  _extends: ImplicitConversionExpr
+
+DifferentiableFunctionExtractOriginalExpr:
+  _extends: ImplicitConversionExpr
+
+ErasureExpr:
+  _extends: ImplicitConversionExpr
+
+ExistentialMetatypeToObjectExpr:
+  _extends: ImplicitConversionExpr
+
+ForeignObjectConversionExpr:
+  _extends: ImplicitConversionExpr
+
+FunctionConversionExpr:
+  _extends: ImplicitConversionExpr
+
+InOutToPointerExpr:
+  _extends: ImplicitConversionExpr
+
+InjectIntoOptionalExpr:
+  _extends: ImplicitConversionExpr
+
+LinearFunctionExpr:
+  _extends: ImplicitConversionExpr
+
+LinearFunctionExtractOriginalExpr:
+  _extends: ImplicitConversionExpr
+
+LinearToDifferentiableFunctionExpr:
+  _extends: ImplicitConversionExpr
+
+LoadExpr:
+  _extends: ImplicitConversionExpr
+
+MetatypeConversionExpr:
+  _extends: ImplicitConversionExpr
+
+PointerToPointerExpr:
+  _extends: ImplicitConversionExpr
+
+ProtocolMetatypeToObjectExpr:
+  _extends: ImplicitConversionExpr
+
+StringToPointerExpr:
+  _extends: ImplicitConversionExpr
+
+UnderlyingToOpaqueExpr:
+  _extends: ImplicitConversionExpr
+
+UnevaluatedInstanceExpr:
+  _extends: ImplicitConversionExpr
+
+UnresolvedTypeConversionExpr:
+  _extends: ImplicitConversionExpr
+
+BuiltinLiteralExpr:
+  _extends: LiteralExpr
+
+InterpolatedStringLiteralExpr:
+  _extends: LiteralExpr
+  interpolation_expr: OpaqueValueExpr?
+  interpolation_count_expr: Expr?
+  literal_capacity_expr: Expr?
+  appending_expr: TapExpr?
+
+RegexLiteralExpr:
+  _extends: LiteralExpr
+
+NilLiteralExpr:
+  _extends: LiteralExpr
+
+ObjectLiteralExpr:
+  _extends: LiteralExpr
+
+DynamicLookupExpr:
+  _extends: LookupExpr
+
+MemberRefExpr:
+  _extends: LookupExpr
+  base_expr: Expr
+
+SubscriptExpr:
+  _extends:
+    - GenericContext
+    - LookupExpr
+  base_expr: Expr
+  arguments: Argument*
+
+OverloadedDeclRefExpr:
+  _extends: OverloadSetRefExpr
+
+DoCatchStmt:
+  _extends: LabeledStmt
+  body: Stmt
+  catches: CaseStmt*
+
+DoStmt:
+  _extends: LabeledStmt
+  body: BraceStmt
+
+ForEachStmt:
+  _extends: LabeledStmt
+  body: BraceStmt
+  where: Expr?
+
+LabeledConditionalStmt:
+  _extends: LabeledStmt
+  condition: StmtCondition
+
+StmtCondition:
+  _extends: AstNode
+  elements: ConditionElement*
+  _dir: stmt
+
+RepeatWhileStmt:
+  _extends: LabeledStmt
+  cond: Expr
+  body: Stmt
+
+SwitchStmt:
+  _extends: LabeledStmt
+  subject_expr: Expr
+  cases: CaseStmt*
+
+BoundGenericClassType:
+  _extends: BoundGenericType
+
+BoundGenericEnumType:
+  _extends: BoundGenericType
+
+BoundGenericStructType:
+  _extends: BoundGenericType
+
+ClassType:
+  _extends: NominalType
+  decl: ClassDecl
+
+EnumType:
+  _extends: NominalType
+
+ProtocolType:
+  _extends: NominalType
+
+StructType:
+  _extends: NominalType
+  decl: StructDecl
+
+ArraySliceType:
+  _extends: UnarySyntaxSugarType
+
+OptionalType:
+  _extends: UnarySyntaxSugarType
+
+VariadicSequenceType:
+  _extends: UnarySyntaxSugarType
+
+ConstructorDecl:
+  _extends: AbstractFunctionDecl
+
+DestructorDecl:
+  _extends: AbstractFunctionDecl
+
+FuncDecl:
+  _extends: AbstractFunctionDecl
+
+SubscriptDecl:
+  _extends: AbstractStorageDecl
+
+VarDecl:
+  _extends: AbstractStorageDecl
+  name: string
+  type: Type
+
+AbstractTypeParamDecl:
+  _extends: TypeDecl
+
+GenericContext:
+  generic_type_params: GenericTypeParamDecl*
+
+GenericTypeDecl:
+  _extends:
+    - GenericContext
+    - TypeDecl
+
+ModuleDecl:
+  _extends: TypeDecl
+
+ConstructorRefCallExpr:
+  _extends: SelfApplyExpr
+
+DotSyntaxCallExpr:
+  _extends: SelfApplyExpr
+
+ConditionalCheckedCastExpr:
+  _extends: CheckedCastExpr
+
+ForcedCheckedCastExpr:
+  _extends: CheckedCastExpr
+
+IsExpr:
+  _extends: CheckedCastExpr
+
+BooleanLiteralExpr:
+  _extends: BuiltinLiteralExpr
+  value: boolean
+
+MagicIdentifierLiteralExpr:
+  _extends: BuiltinLiteralExpr
+  kind: string
+
+NumberLiteralExpr:
+  _extends: BuiltinLiteralExpr
+
+StringLiteralExpr:
+  _extends: BuiltinLiteralExpr
+  value: string
+
+DynamicMemberRefExpr:
+  _extends: DynamicLookupExpr
+
+DynamicSubscriptExpr:
+  _extends: DynamicLookupExpr
+
+GuardStmt:
+  _extends: LabeledConditionalStmt
+  body: BraceStmt
+
+IfStmt:
+  _extends: LabeledConditionalStmt
+  then: Stmt
+  else: Stmt?
+
+WhileStmt:
+  _extends: LabeledConditionalStmt
+  body: Stmt
+
+AccessorDecl:
+  _extends: FuncDecl
+
+ConcreteFuncDecl:
+  _extends: FuncDecl
+
+ConcreteVarDecl:
+  _extends: VarDecl
+  introducer_int: int
+
+ParamDecl:
+  _extends: VarDecl
+
+AssociatedTypeDecl:
+  _extends: AbstractTypeParamDecl
+
+GenericTypeParamDecl:
+  _extends: AbstractTypeParamDecl
+
+OpaqueTypeDecl:
+  _extends: GenericTypeDecl
+
+TypeAliasDecl:
+  _extends: GenericTypeDecl
+
+FloatLiteralExpr:
+  _extends: NumberLiteralExpr
+  string_value: string
+
+IntegerLiteralExpr:
+  _extends: NumberLiteralExpr
+  string_value: string