[dev.types] all: merge master into dev.types

Change-Id: Ia6964cb4e09153c15cc9c5b441373d1b3cb8f757

src/internal/types/ast.go

@@ -0,0 +1,507 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file defines a collection of interfaces providing an AST abstraction,
+// for use in a type checker that operates on multiple concrete ASTs.
+
+package types
+
+import (
+	"go/ast"
+	"go/token"
+)
+
+type Pos interface {
+	IsKnown() bool
+	Before(pos Pos) bool
+	String() string
+}
+
+// Nodes
+type (
+	Node interface {
+		Pos() Pos
+	}
+
+	File interface {
+		Package() Pos
+		Name() Ident
+
+		// TODO: devise a new schema for *Len methods. DeclsLen is too clunky.
+
+		DeclsLen() int
+		Decl(i int) Decl
+
+		Node
+	}
+
+	FieldList interface {
+		Len() int
+		Field(i int) Field
+
+		Node
+	}
+
+	Field interface {
+		NamesLen() int
+		Name(i int) Ident
+		Type() Expr
+		Tag() BasicLit
+
+		Node
+	}
+)
+
+// Decls
+type (
+	Decl interface {
+		ADecl()
+		Node
+	}
+
+	BadDecl interface {
+		ABadDecl()
+		Decl
+	}
+
+	GenDecl interface {
+		Tok() token.Token
+		SpecsLen() int
+		Spec(i int) Spec
+
+		AGenDecl()
+		Decl
+	}
+
+	FuncDecl interface {
+		Recv() FieldList
+		Name() Ident
+		Type() FuncType
+		Body() BlockStmt
+
+		AFuncDecl()
+		Decl
+	}
+)
+
+// Specs
+type (
+	Spec interface {
+		ASpec()
+		Node
+	}
+
+	// TODO: consolidate these specs with decls.
+
+	ValueSpec interface {
+		NamesLen() int
+		Name(i int) Ident
+		Type() Expr
+		ValuesLen() int
+		Value(i int) Expr
+
+		AValueSpec()
+		Spec
+	}
+
+	TypeSpec interface {
+		Name() Ident
+		Assign() Pos
+		Type() Expr
+
+		ATypeSpec()
+		Spec
+	}
+
+	ImportSpec interface {
+		Path() BasicLit
+		Name() Ident
+
+		AnImportSpec()
+		Spec
+	}
+)
+
+// Exprs
+type (
+	Expr interface {
+		AnExpr()
+		Node
+	}
+
+	Ident interface {
+		Name() string
+
+		AnIdent()
+		Expr
+	}
+
+	SelectorExpr interface {
+		X() Expr
+		Sel() Ident
+
+		ASelectorExpr()
+		Expr
+	}
+
+	BadExpr interface {
+		ABadExpr()
+		Expr
+	}
+
+	DotDotDot interface {
+		Elt() Expr
+
+		ADotDotDot()
+		Expr
+	}
+
+	BasicLit interface {
+		Kind() token.Token
+		Value() string
+
+		ABasicLit()
+		Expr
+	}
+
+	FuncLit interface {
+		Type() Expr
+		Body() BlockStmt
+
+		AFuncLit()
+		Expr
+	}
+
+	CompositeLit interface {
+		Type() Expr
+		EltsLen() int
+		Elt(i int) Expr
+		Rbrace() Pos
+
+		ACompositeLit()
+		Expr
+	}
+
+	ParenExpr interface {
+		X() Expr
+
+		AParenExpr()
+		Expr
+	}
+
+	IndexExpr interface {
+		X() Expr
+		Index() Expr
+
+		AnIndexExpr()
+		Expr
+	}
+
+	SliceExpr interface {
+		X() Expr
+		Low() Expr
+		High() Expr
+		Max() Expr
+		Slice3() bool
+		Rbrack() Pos
+
+		ASliceExpr()
+		Expr
+	}
+
+	TypeAssertExpr interface {
+		X() Expr
+		Type() Expr
+
+		ATypeAssertExpr()
+		Expr
+	}
+
+	CallExpr interface {
+		ArgsLen() int
+		Arg(i int) Expr
+		Fun() Expr
+		Ellipsis() Pos
+		Rparen() Pos
+
+		ACallExpr()
+		Expr
+	}
+
+	StarExpr interface {
+		Expr
+		AStarExpr()
+
+		X() Expr
+	}
+
+	UnaryExpr interface {
+		Expr
+		AUnaryExpr()
+
+		Op() token.Token
+		X() Expr
+	}
+
+	BinaryExpr interface {
+		Op() token.Token
+		X() Expr
+		Y() Expr
+
+		ABinaryExpr()
+		Expr
+	}
+
+	KeyValueExpr interface {
+		Key() Expr
+		Value() Expr
+
+		AKeyValueExpr()
+		Expr
+	}
+
+	ArrayType interface {
+		Len() Expr
+		Elt() Expr
+
+		AnArrayType()
+		Expr
+	}
+
+	StructType interface {
+		Fields() FieldList
+
+		AStructType()
+		Expr
+	}
+
+	FuncType interface {
+		Params() FieldList
+		Results() FieldList
+
+		AFuncType()
+		Expr
+	}
+
+	InterfaceType interface {
+		Methods() FieldList
+
+		AnInterfaceType()
+		Expr
+	}
+
+	MapType interface {
+		Key() Expr
+		Value() Expr
+
+		AMapType()
+		Expr
+	}
+
+	ChanType interface {
+		// TODO: replace this return type
+		Dir() ast.ChanDir
+		Value() Expr
+
+		AChanType()
+		Expr
+	}
+)
+
+type ExprList interface {
+	Len() int
+	Expr(i int) Expr
+}
+
+// Stmts
+type (
+	Stmt interface {
+		AStmt()
+		Node
+	}
+
+	BadStmt interface {
+		ABadStmt()
+		Stmt
+	}
+
+	DeclStmt interface {
+		Decl() Decl
+
+		ADeclStmt()
+		Stmt
+	}
+
+	EmptyStmt interface {
+		AnEmptyStmt()
+		Stmt
+	}
+
+	LabeledStmt interface {
+		Label() Ident
+		Stmt() Stmt
+
+		ALabeledStmt()
+		Stmt
+	}
+
+	ExprStmt interface {
+		X() Expr
+
+		AnExprStmt()
+		Stmt
+	}
+
+	SendStmt interface {
+		Chan() Expr
+		Value() Expr
+		Arrow() Pos
+
+		ASendStmt()
+		Stmt
+	}
+
+	IncDecStmt interface {
+		Tok() token.Token
+		TokPos() Pos
+		X() Expr
+
+		AnIncDecStmt()
+		Stmt
+	}
+
+	AssignStmt interface {
+		Lhs() ExprList
+		LhsLen() int
+		LhsExpr(i int) Expr
+		RhsLen() int
+		RhsExpr(i int) Expr
+		Rhs() ExprList
+		Tok() token.Token
+		TokPos() Pos
+
+		AnAssignStmt()
+		Stmt
+	}
+
+	GoStmt interface {
+		Call() CallExpr
+
+		AGoStmt()
+		Stmt
+	}
+
+	DeferStmt interface {
+		Call() CallExpr
+
+		ADeferStmt()
+		Stmt
+	}
+
+	ReturnStmt interface {
+		Results() ExprList
+		ResultsLen() int
+		Result(i int) Expr
+		Return() Pos
+
+		AReturnStmt()
+		Stmt
+	}
+
+	BranchStmt interface {
+		Tok() token.Token
+		Label() Ident
+
+		ABranchStmt()
+		Stmt
+	}
+
+	BlockStmt interface {
+		List() StmtList
+		Lbrace() Pos
+		Rbrace() Pos
+
+		ABlockStmt()
+		Stmt
+	}
+
+	IfStmt interface {
+		Init() Stmt
+		Cond() Expr
+		Body() BlockStmt
+		Else() Stmt
+
+		AnIfStmt()
+		Stmt
+	}
+
+	CaseClause interface {
+		ListLen() int
+		Item(i int) Expr
+		Body() StmtList
+
+		ACaseClause()
+		Stmt
+	}
+
+	SwitchStmt interface {
+		Init() Stmt
+		Tag() Expr
+		Body() BlockStmt
+
+		ASwitchStmt()
+		Stmt
+	}
+
+	TypeSwitchStmt interface {
+		Init() Stmt
+		Assign() Stmt
+		Body() BlockStmt
+
+		ATypeSwitchStmt()
+		Stmt
+	}
+
+	CommClause interface {
+		Stmt
+		ACommClause()
+
+		Comm() Stmt
+		Body() StmtList
+	}
+
+	SelectStmt interface {
+		Stmt
+		ASelectStmt()
+
+		Body() BlockStmt
+	}
+
+	ForStmt interface {
+		Init() Stmt
+		Cond() Expr
+		Post() Stmt
+		Body() BlockStmt
+
+		AForStmt()
+		Stmt
+	}
+
+	RangeStmt interface {
+		Stmt
+		ARangeStmt()
+
+		Key() Expr
+		Value() Expr
+		X() Expr
+		Body() BlockStmt
+		Tok() token.Token
+		TokPos() Pos
+	}
+)
+
+type StmtList interface {
+	Len() int
+	Stmt(i int) Stmt
+}