mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-10-01 16:35:53 +01:00
Jon Ross-Perkins
11deb14dc6
The problem I'm trying to solve is: `var x: i32 = x;`. This change makes it so that name lookup fails, by removing `x` from name lookup between the `=` and `;`. `var x: i32` still adds to name lookup to handle future situations like `var (x: i32, x: i32);` which is still a redefinition of `x`; if we don't add `x` to name lookup, it gets harder to catch that example. The VariableDeclaration/VariableInitializer refactor in ParseTree supports this by given a bracketing-like structure for semantics to cue that it's entering an initialization expression. With this, VariableInitializer can remove the name lookup and queue it to be restored. VariableDeclaration doesn't need to change too much since it's still bracketed by VariableIntroducer, and so we just traverse slightly differently. Note this also incidentally changes a little about NameReference, that it's returning the storage consistently instead of the name. You can see this e.g. in global_lookup.carbon, `Assign(node8, node4): node2;` using node4 (VarStorage) instead of Node5 (BindName). Really either _could_ work, since from a BindName we can get to the VarStorage, and that may be reason to switch later if we find it preferable to have the BindName for whatever reason. But the *actual* value in NameLookup is a BindName so that errors can associate with the _name_ instead of the "storage" parse node, which is currently the `:`. This is mainly for fail_duplicate_decl.carbon, which has a "Previous definition" note that points at the storage's parse node.
315 lines
11 KiB
Modula-2
315 lines
11 KiB
Modula-2
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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// Note that this is an X-macro header.
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//
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// It does not use `#include` guards, and instead is designed to be `#include`ed
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// after the x-macro is defined in order for its inclusion to expand to the
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// desired output.
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//
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// x-macros come in three forms:
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// CARBON_PARSE_NODE_KIND(Name)
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// Used as a fallback if other macros are missing.
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// CARBON_PARSE_NODE_KIND_BRACKET(Name, BracketName)
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// Defines a bracketed node kind. BracketName should refer to the node kind
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// that is the _start_ of the bracketed range.
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// CARBON_PARSE_NODE_KIND_CHILD_COUNT(Name, ChildCount)
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// Defines a parse node with a set number of children, often 0. This count
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// must be correct even when the node contains errors.
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//
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// Macro definitions will be removed at the end of this file to clean up.
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#if !(defined(CARBON_PARSE_NODE_KIND) || \
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(defined(CARBON_PARSE_NODE_KIND_BRACKET) && \
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defined(CARBON_PARSE_NODE_KIND_CHILD_COUNT)))
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#error "Must define CARBON_PARSE_NODE_KIND family x-macros to use this file."
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#endif
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// The BRACKET and CHILD_COUNT macros will use CARBON_PARSE_NODE_KIND by default
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// when undefined.
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#ifndef CARBON_PARSE_NODE_KIND_BRACKET
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#define CARBON_PARSE_NODE_KIND_BRACKET(Name, ...) CARBON_PARSE_NODE_KIND(Name)
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#endif
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#ifndef CARBON_PARSE_NODE_KIND_CHILD_COUNT
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#define CARBON_PARSE_NODE_KIND_CHILD_COUNT(Name, ...) \
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CARBON_PARSE_NODE_KIND(Name)
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#endif
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// The end of the file.
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(FileEnd, 0)
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// An empty declaration, such as `;`.
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(EmptyDeclaration, 0)
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// A name.
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(DeclaredName, 0)
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// `package`:
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// PackageIntroducer
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// _external_: DeclaredName
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// _external_: Literal
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// PackageLibrary
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// PackageApi or PackageImpl
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// PackageDirective
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(PackageIntroducer, 0)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(PackageApi, 0)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(PackageImpl, 0)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(PackageLibrary, 1)
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CARBON_PARSE_NODE_KIND_BRACKET(PackageDirective, PackageIntroducer)
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// A code block:
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// CodeBlockStart
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// _external_: statements
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// CodeBlock
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(CodeBlockStart, 0)
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CARBON_PARSE_NODE_KIND_BRACKET(CodeBlock, CodeBlockStart)
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// `fn`:
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// FunctionIntroducer
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// DeclaredName
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// _external_: ParameterList
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// _external_: type expression
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// ReturnType
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// FunctionDefinitionStart
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// _external_: statements
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// FunctionDefinition
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//
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// The above is a definition; for a declaration, FunctionDeclaration will end it
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// where FunctionDefinitionStart is for a definition.
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(FunctionIntroducer, 0)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(ReturnType, 1)
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CARBON_PARSE_NODE_KIND_BRACKET(FunctionDefinitionStart, FunctionIntroducer)
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CARBON_PARSE_NODE_KIND_BRACKET(FunctionDefinition, FunctionDefinitionStart)
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CARBON_PARSE_NODE_KIND_BRACKET(FunctionDeclaration, FunctionIntroducer)
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// A parameter list:
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// ParamertListStart
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// _external_: expression
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// ParameterListComma
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// ParameterList
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//
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// Expressions and ParameterListComma may repeat with ParameterListComma as a
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// separator.
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(ParameterListStart, 0)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(ParameterListComma, 0)
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CARBON_PARSE_NODE_KIND_BRACKET(ParameterList, ParameterListStart)
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// A pattern binding, such as `name: Type`:
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// DeclaredName
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// _external_: type expression
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// PatternBinding
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(PatternBinding, 2)
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// `var`:
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// VariableIntroducer
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// _external_: PatternBinding
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// optional VariableInitializer
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// optional _external_: expression
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// VariableDeclaration
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//
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// The VariableInitializer and following expression are paired: either both will
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// be present, or neither will.
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(VariableIntroducer, 0)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(VariableInitializer, 0)
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CARBON_PARSE_NODE_KIND_BRACKET(VariableDeclaration, VariableIntroducer)
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// An expression statement:
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// _external_: expression
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// ExpressionStatement
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(ExpressionStatement, 1)
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// `break`:
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// BreakStatementStart
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// BreakStatement
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(BreakStatementStart, 0)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(BreakStatement, 1)
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// `continue`:
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// ContinueStatementStart
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// ContinueStatement
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(ContinueStatementStart, 0)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(ContinueStatement, 1)
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// `return`:
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// ReturnStatementStart
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// _external_: expression
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// ReturnStatement
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//
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// The child expression is optional.
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(ReturnStatementStart, 0)
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CARBON_PARSE_NODE_KIND_BRACKET(ReturnStatement, ReturnStatementStart)
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// `for`:
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// ForHeaderStart
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// VariableIntroducer
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// _external_: PatternBinding
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// _external_: type expression
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// ForIn
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// _external_: expression
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// ForHeader
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// _external_: CodeBlock
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// ForStatement
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//
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// Versus a normal `var`, ForIn replaces VariableDeclaration.
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(ForHeaderStart, 0)
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CARBON_PARSE_NODE_KIND_BRACKET(ForIn, VariableIntroducer)
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CARBON_PARSE_NODE_KIND_BRACKET(ForHeader, ForHeaderStart)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(ForStatement, 2)
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// `if` + `else`:
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// IfConditionStart
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// _external_: expression
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// IfCondition
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// _external_: CodeBlock
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// IfStatementElse
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// _external_: CodeBlock or IfStatement
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// IfStatement
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//
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// IfStatementElse and the following node are optional based on `else` presence.
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(IfConditionStart, 0)
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CARBON_PARSE_NODE_KIND_BRACKET(IfCondition, IfConditionStart)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(IfStatementElse, 0)
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CARBON_PARSE_NODE_KIND_BRACKET(IfStatement, IfCondition)
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// `while`:
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// WhileConditionStart
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// _external_: expression
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// WhileCondition
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// _external_: CodeBlock
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// WhileStatement
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(WhileConditionStart, 0)
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CARBON_PARSE_NODE_KIND_BRACKET(WhileCondition, WhileConditionStart)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(WhileStatement, 2)
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// Parenthesized expressions:
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// ParenExpressionOrTupleLiteralStart
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// _external_: expression
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// ParenExpression
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// Tuples:
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// ParenExpressionOrTupleLiteralStart
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// _external_: expression
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// TupleLiteralComma
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// TupleLiteral
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//
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// Expressions and TupleLiteralComma may repeat with TupleLiteralComma as a
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// separator.
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(ParenExpressionOrTupleLiteralStart, 0)
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CARBON_PARSE_NODE_KIND_BRACKET(ParenExpression,
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ParenExpressionOrTupleLiteralStart)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(TupleLiteralComma, 0)
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CARBON_PARSE_NODE_KIND_BRACKET(TupleLiteral, ParenExpressionOrTupleLiteralStart)
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// Call expressions, such as `a()`:
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// _external_: expression
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// CallExpressionStart
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// _external_: expression
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// CallExpressionComma
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// CallExpression
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//
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// Expressions and CallExpressionComma may repeat with CallExpressionComma as a
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// separator.
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(CallExpressionStart, 1)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(CallExpressionComma, 0)
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CARBON_PARSE_NODE_KIND_BRACKET(CallExpression, CallExpressionStart)
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// A designator expression, such as `a.b`:
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// _external_: DesignatedName or lhs expression
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// _external_: DesignatedName
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// DesignatorExpression
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(DesignatedName, 0)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(DesignatorExpression, 2)
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// A literal.
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(Literal, 0)
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// A reference to an identifier.
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(NameReference, 0)
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// A prefix operator:
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// _external_: expression
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// PrefixOperator
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(PrefixOperator, 1)
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// An infix operator:
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// _external_: lhs expression
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// _external_: rhs expression
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// InfixOperator
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(InfixOperator, 2)
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// A postfix operator:
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// _external_: expression
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// PostfixOperator
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(PostfixOperator, 1)
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// Struct literals, such as `{.a = 0}`:
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// StructLiteralOrStructTypeLiteralStart
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// _external_: DesignatedName
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// StructFieldDesignator
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// _external_: expression
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// StructFieldValue
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// StructComma
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// StructLiteral
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//
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//
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// Struct type literals, such as `{.a: i32}`:
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// _external_: DesignatedName
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// StructFieldDesignator
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// _external_: type expression
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// StructFieldType
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// StructComma
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// StructTypeLiteral
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//
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// Elements (StructFieldValue and StructFieldType, respectively) and StructComma
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// may repeat with StructComma as a separator.
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//
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// When a valid StructFieldType or StructFieldValue cannot be formed, elements
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// may be replaced by StructFieldUnknown, which may have a preceding sibling
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// StructFieldDesignator if one was successfully parsed.
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(StructLiteralOrStructTypeLiteralStart, 0)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(StructFieldDesignator, 1)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(StructFieldValue, 2)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(StructFieldType, 2)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(StructFieldUnknown, 0)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(StructComma, 0)
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CARBON_PARSE_NODE_KIND_BRACKET(StructLiteral,
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StructLiteralOrStructTypeLiteralStart)
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CARBON_PARSE_NODE_KIND_BRACKET(StructTypeLiteral,
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StructLiteralOrStructTypeLiteralStart)
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// `interface`:
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// _external_: DeclaredName
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// InterfaceBodyStart
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// _external_: statements
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// InterfaceBodyEnd
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// InterfaceDefinition
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(InterfaceBodyStart, 0)
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CARBON_PARSE_NODE_KIND_BRACKET(InterfaceBody, InterfaceBodyStart)
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CARBON_PARSE_NODE_KIND_BRACKET(InterfaceDefinition, DeclaredName)
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// A pattern binding for `self` deduced parameter:
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// `self`
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// _external_: type expression
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// SelfDeducedParameter
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(SelfDeducedParameter, 0)
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// A pattern binding for `addr self` deduced parameter:
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// `addr self`
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// _external_: type expression
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// SelfDeducedParameter
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// CARBON_PARSE_NODE_KIND_CHILD_COUNT(SelfDeducedParameterAddress, 1)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(Address, 1)
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(SelfType, 0)
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// Deduced parameters, such as `[self: Self]`:
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// DeducedParameterListStart
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// _external_: Address or PatternBinding
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// DeducedParameterList
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CARBON_PARSE_NODE_KIND_CHILD_COUNT(DeducedParameterListStart, 0)
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CARBON_PARSE_NODE_KIND_BRACKET(DeducedParameterList, DeducedParameterListStart)
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#undef CARBON_PARSE_NODE_KIND
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#undef CARBON_PARSE_NODE_KIND_BRACKET
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#undef CARBON_PARSE_NODE_KIND_CHILD_COUNT
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