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3b0180b1b0
Parse '_' as a DiscardAssignmentExpr. Type-check it as an lvalue, and check that it only appears in the LHS of AssignExprs. During matching pattern resolution, convert it into an AnyPattern. In SILGen, when we see '_' in the LHS of an assignment, ignore the corresponding RHS rvalue. Swift SVN r8848
687 lines
23 KiB
C++
687 lines
23 KiB
C++
//===--- ParsePattern.cpp - Swift Language Parser for Patterns ------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See http://swift.org/LICENSE.txt for license information
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// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// Pattern Parsing and AST Building
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//
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//===----------------------------------------------------------------------===//
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#include "swift/Parse/Parser.h"
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#include "swift/AST/ExprHandle.h"
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#include "llvm/ADT/StringMap.h"
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using namespace swift;
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/// Parse function arguments.
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/// func-arguments:
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/// curried-arguments | selector-arguments
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/// curried-arguments:
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/// pattern-tuple+
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/// selector-arguments:
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/// '(' selector-element ')' (identifier '(' selector-element ')')+
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/// selector-element:
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/// identifier '(' pattern-atom (':' type-annotation)? ('=' expr)? ')'
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static ParserStatus
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parseCurriedFunctionArguments(Parser &P,
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SmallVectorImpl<Pattern *> &argPat,
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SmallVectorImpl<Pattern *> &bodyPat) {
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// parseFunctionArguments parsed the first argument pattern.
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// Parse additional curried argument clauses as long as we can.
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while (P.Tok.is(tok::l_paren)) {
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ParserResult<Pattern> pattern = P.parsePatternTuple(/*AllowInitExpr=*/false);
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if (pattern.isNull() || pattern.hasCodeCompletion())
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return pattern;
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argPat.push_back(pattern.get());
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bodyPat.push_back(pattern.get());
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}
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return makeParserSuccess();
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}
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/// \brief Determine the kind of a default argument given a parsed
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/// expression that has not yet been type-checked.
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static DefaultArgumentKind getDefaultArgKind(ExprHandle *init) {
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if (!init || !init->getExpr())
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return DefaultArgumentKind::None;
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auto magic = dyn_cast<MagicIdentifierLiteralExpr>(init->getExpr());
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if (!magic)
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return DefaultArgumentKind::Normal;
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switch (magic->getKind()) {
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case MagicIdentifierLiteralExpr::Column:
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return DefaultArgumentKind::Column;
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case MagicIdentifierLiteralExpr::File:
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return DefaultArgumentKind::File;
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case MagicIdentifierLiteralExpr::Line:
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return DefaultArgumentKind::Line;
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}
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}
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static void recoverFromBadSelectorArgument(Parser &P) {
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while (P.Tok.isNot(tok::eof) && P.Tok.isNot(tok::r_paren) &&
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P.Tok.isNot(tok::l_brace) && P.Tok.isNot(tok::r_brace) &&
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!P.isStartOfStmt(P.Tok) &&
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!P.isStartOfDecl(P.Tok, P.peekToken())) {
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P.skipSingle();
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}
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P.consumeIf(tok::r_paren);
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}
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static ParserStatus
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parseSelectorArgument(Parser &P,
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SmallVectorImpl<TuplePatternElt> &argElts,
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SmallVectorImpl<TuplePatternElt> &bodyElts,
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llvm::StringMap<VarDecl *> &selectorNames,
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SourceLoc &rp) {
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ParserResult<Pattern> ArgPatternRes = P.parsePatternIdentifier();
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assert(ArgPatternRes.isNonNull() &&
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"selector argument did not start with an identifier!");
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Pattern *ArgPattern = ArgPatternRes.get();
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ArgPattern->setImplicit();
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// Check that a selector name isn't used multiple times, which would
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// lead to the function type having multiple arguments with the same name.
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if (NamedPattern *name = dyn_cast<NamedPattern>(ArgPattern)) {
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VarDecl *decl = name->getDecl();
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decl->setImplicit();
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StringRef id = decl->getName().str();
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auto prevName = selectorNames.find(id);
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if (prevName != selectorNames.end()) {
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P.diagnoseRedefinition(prevName->getValue(), decl);
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} else {
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selectorNames[id] = decl;
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}
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}
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if (!P.Tok.is(tok::l_paren)) {
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P.diagnose(P.Tok, diag::func_selector_without_paren);
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return makeParserError();
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}
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P.consumeToken(tok::l_paren);
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if (P.Tok.is(tok::r_paren)) {
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P.diagnose(P.Tok, diag::func_selector_with_not_one_argument);
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rp = P.consumeToken(tok::r_paren);
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return makeParserError();
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}
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ParserResult<Pattern> BodyPatternRes = P.parsePatternAtom();
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if (BodyPatternRes.isNull()) {
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recoverFromBadSelectorArgument(P);
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return makeParserError();
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}
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Pattern *BodyPattern = BodyPatternRes.get();
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if (P.consumeIf(tok::colon)) {
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ParserResult<TypeRepr> type = P.parseTypeAnnotation();
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ParserStatus Status = type;
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if (type.isNull()) {
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type = makeParserErrorResult(
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new (P.Context) ErrorTypeRepr(P.PreviousLoc));
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}
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if (type.isParseError()) {
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recoverFromBadSelectorArgument(P);
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}
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ArgPattern = new (P.Context) TypedPattern(ArgPattern, type.get(),
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/*Implicit=*/true);
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BodyPattern = new (P.Context) TypedPattern(BodyPattern, type.get());
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if (Status.isError())
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return Status;
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}
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ExprHandle *init = nullptr;
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if (P.consumeIf(tok::equal)) {
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ParserResult<Expr> initR =
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P.parseExpr(diag::expected_init_value);
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if (initR.hasCodeCompletion()) {
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recoverFromBadSelectorArgument(P);
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return makeParserCodeCompletionStatus();
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}
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if (initR.isNull()) {
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recoverFromBadSelectorArgument(P);
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return makeParserError();
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}
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init = ExprHandle::get(P.Context, initR.get());
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}
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if (P.Tok.is(tok::comma)) {
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P.diagnose(P.Tok, diag::func_selector_with_not_one_argument);
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recoverFromBadSelectorArgument(P);
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return makeParserError();
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}
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if (P.Tok.isNot(tok::r_paren)) {
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P.diagnose(P.Tok, diag::expected_rparen_tuple_pattern_list);
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return makeParserError();
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}
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rp = P.consumeToken(tok::r_paren);
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argElts.push_back(TuplePatternElt(ArgPattern, init,
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getDefaultArgKind(init)));
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bodyElts.push_back(TuplePatternElt(BodyPattern, init,
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getDefaultArgKind(init)));
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return makeParserSuccess();
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}
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static Pattern *getFirstSelectorPattern(ASTContext &Context,
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const Pattern *argPattern,
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SourceLoc loc)
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{
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Pattern *pattern = new (Context) AnyPattern(loc, /*Implicit=*/true);
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if (auto typed = dyn_cast<TypedPattern>(argPattern)) {
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pattern = new (Context) TypedPattern(pattern, typed->getTypeLoc(),
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/*Implicit=*/true);
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}
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return pattern;
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}
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static ParserStatus
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parseSelectorFunctionArguments(Parser &P,
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SmallVectorImpl<Pattern *> &ArgPatterns,
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SmallVectorImpl<Pattern *> &BodyPatterns,
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Pattern *FirstPattern) {
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SourceLoc LParenLoc;
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SourceLoc RParenLoc;
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SmallVector<TuplePatternElt, 8> ArgElts;
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SmallVector<TuplePatternElt, 8> BodyElts;
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// For the argument pattern, try to convert the first parameter pattern to
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// an anonymous AnyPattern of the same type as the body parameter.
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if (ParenPattern *FirstParen = dyn_cast<ParenPattern>(FirstPattern)) {
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BodyElts.push_back(TuplePatternElt(FirstParen->getSubPattern()));
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LParenLoc = FirstParen->getLParenLoc();
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RParenLoc = FirstParen->getRParenLoc();
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ArgElts.push_back(TuplePatternElt(
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getFirstSelectorPattern(P.Context,
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FirstParen->getSubPattern(),
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FirstParen->getLoc())));
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} else if (TuplePattern *FirstTuple = dyn_cast<TuplePattern>(FirstPattern)) {
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LParenLoc = FirstTuple->getLParenLoc();
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RParenLoc = FirstTuple->getRParenLoc();
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if (FirstTuple->getNumFields() != 1) {
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P.diagnose(P.Tok, diag::func_selector_with_not_one_argument);
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}
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if (FirstTuple->getNumFields() >= 1) {
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const TuplePatternElt &FirstElt = FirstTuple->getFields()[0];
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BodyElts.push_back(FirstElt);
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ArgElts.push_back(TuplePatternElt(
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getFirstSelectorPattern(P.Context,
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FirstElt.getPattern(),
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FirstTuple->getLoc()),
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FirstElt.getInit(),
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FirstElt.getDefaultArgKind()));
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} else {
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// Recover by creating a '(_: ())' pattern.
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TuplePatternElt FirstElt(
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new (P.Context) TypedPattern(
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new (P.Context) AnyPattern(FirstTuple->getLParenLoc()),
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TupleTypeRepr::create(P.Context, {},
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FirstTuple->getSourceRange(),
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SourceLoc())));
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BodyElts.push_back(FirstElt);
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ArgElts.push_back(FirstElt);
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}
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} else
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llvm_unreachable("unexpected function argument pattern!");
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assert(ArgElts.size() > 0);
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assert(BodyElts.size() > 0);
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// Parse additional selectors as long as we can.
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llvm::StringMap<VarDecl *> SelectorNames;
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ParserStatus Status;
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for (;;) {
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if (P.isStartOfBindingName(P.Tok)) {
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Status |= parseSelectorArgument(P, ArgElts, BodyElts, SelectorNames,
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RParenLoc);
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continue;
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}
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if (P.Tok.is(tok::l_paren)) {
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P.diagnose(P.Tok, diag::func_selector_with_curry);
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// FIXME: better recovery: just parse a tuple instead of skipping tokens.
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P.skipUntilDeclRBrace(tok::l_brace);
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Status.setIsParseError();
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}
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break;
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}
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ArgPatterns.push_back(
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TuplePattern::create(P.Context, LParenLoc, ArgElts, RParenLoc,
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/*hasVarArg=*/false,SourceLoc(), /*Implicit=*/true));
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BodyPatterns.push_back(
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TuplePattern::create(P.Context, LParenLoc, BodyElts, RParenLoc));
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return Status;
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}
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ParserStatus
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Parser::parseFunctionArguments(SmallVectorImpl<Pattern *> &ArgPatterns,
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SmallVectorImpl<Pattern *> &BodyPatterns,
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bool &HasSelectorStyleSignature) {
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// Parse the first function argument clause.
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ParserResult<Pattern> FirstPattern = parsePatternTuple(/*AllowInitExpr=*/true);
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if (FirstPattern.isNull()) {
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// Recover by creating a '()' pattern.
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auto EmptyTuplePattern =
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TuplePattern::create(Context, Tok.getLoc(), {}, Tok.getLoc());
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ArgPatterns.push_back(EmptyTuplePattern);
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BodyPatterns.push_back(EmptyTuplePattern);
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}
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// FIXME: more strict check would be to look for l_paren as well.
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if (isStartOfBindingName(Tok)) {
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// This looks like a selector-style argument. Try to convert the first
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// argument pattern into a single argument type and parse subsequent
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// selector forms.
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HasSelectorStyleSignature = true;
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return ParserStatus(FirstPattern) |
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parseSelectorFunctionArguments(*this, ArgPatterns, BodyPatterns,
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FirstPattern.get());
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} else {
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ArgPatterns.push_back(FirstPattern.get());
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BodyPatterns.push_back(FirstPattern.get());
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return ParserStatus(FirstPattern) |
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parseCurriedFunctionArguments(*this, ArgPatterns, BodyPatterns);
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}
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}
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/// parseFunctionSignature - Parse a function definition signature.
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/// func-signature:
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/// func-arguments func-signature-result?
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/// func-signature-result:
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/// '->' type
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///
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/// Note that this leaves retType as null if unspecified.
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ParserStatus
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Parser::parseFunctionSignature(SmallVectorImpl<Pattern *> &argPatterns,
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SmallVectorImpl<Pattern *> &bodyPatterns,
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TypeRepr *&retType,
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bool &HasSelectorStyleSignature) {
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HasSelectorStyleSignature = false;
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ParserStatus Status;
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// We force first type of a func declaration to be a tuple for consistency.
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if (Tok.is(tok::l_paren))
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Status = parseFunctionArguments(argPatterns, bodyPatterns,
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HasSelectorStyleSignature);
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else {
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diagnose(Tok, diag::func_decl_without_paren);
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Status = makeParserError();
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// Recover by creating a '() -> ?' signature.
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auto *EmptyTuplePattern =
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TuplePattern::create(Context, Tok.getLoc(), {}, Tok.getLoc());
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argPatterns.push_back(EmptyTuplePattern);
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bodyPatterns.push_back(EmptyTuplePattern);
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}
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// If there's a trailing arrow, parse the rest as the result type.
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if (Tok.is(tok::arrow) || Tok.is(tok::colon)) {
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if (!consumeIf(tok::arrow)) {
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// FixIt ':' to '->'.
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diagnose(Tok, diag::func_decl_expected_arrow)
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.fixItReplace(SourceRange(Tok.getLoc()), "->");
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consumeToken(tok::colon);
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}
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ParserResult<TypeRepr> ResultType =
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parseType(diag::expected_type_function_result);
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if (ResultType.hasCodeCompletion())
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return ResultType;
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retType = ResultType.getPtrOrNull();
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if (!retType) {
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Status.setIsParseError();
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return Status;
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}
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} else {
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// Otherwise, we leave retType null.
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retType = nullptr;
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}
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return Status;
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}
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ParserStatus
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Parser::parseConstructorArguments(Pattern *&ArgPattern, Pattern *&BodyPattern,
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bool &HasSelectorStyleSignature) {
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HasSelectorStyleSignature = false;
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// It's just a pattern. Parse it.
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if (Tok.is(tok::l_paren)) {
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ParserResult<Pattern> Params = parsePatternTuple(/*AllowInitExpr=*/true);
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// If we failed to parse the pattern, create an empty tuple to recover.
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if (Params.isNull()) {
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Params = makeParserResult(Params,
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TuplePattern::createSimple(Context, Tok.getLoc(), {}, Tok.getLoc()));
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}
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ArgPattern = Params.get();
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BodyPattern = ArgPattern->clone(Context);
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return Params;
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}
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if (!isStartOfBindingName(Tok)) {
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// Complain that we expected '(' or a parameter name.
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{
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auto diag = diagnose(Tok, diag::expected_lparen_initializer);
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if (Tok.is(tok::l_brace))
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diag.fixItInsert(Tok.getLoc(), "() ");
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}
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// Create an empty tuple to recover.
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ArgPattern = TuplePattern::createSimple(Context, Tok.getLoc(), {},
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Tok.getLoc());
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BodyPattern = ArgPattern->clone(Context);
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return makeParserError();
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}
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// We have the start of a binding name, so this is a selector-style
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// declaration.
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HasSelectorStyleSignature = true;
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// This is not a parenthesis, but we should provide a reasonable source range
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// for parameters.
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SourceLoc LParenLoc = Tok.getLoc();
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// Parse additional selectors as long as we can.
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llvm::StringMap<VarDecl *> selectorNames;
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ParserStatus Status;
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SmallVector<TuplePatternElt, 4> ArgElts;
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SmallVector<TuplePatternElt, 4> BodyElts;
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SourceLoc RParenLoc;
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for (;;) {
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if (isStartOfBindingName(Tok)) {
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Status |= parseSelectorArgument(*this, ArgElts, BodyElts, selectorNames,
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RParenLoc);
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continue;
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}
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if (Tok.is(tok::l_paren)) {
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// FIXME: Should we assume this is '_'?
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diagnose(Tok, diag::func_selector_with_curry);
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// FIXME: better recovery: just parse a tuple instead of skipping tokens.
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skipUntilDeclRBrace(tok::l_brace);
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Status.setIsParseError();
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}
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break;
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}
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ArgPattern = TuplePattern::create(Context, LParenLoc, ArgElts, RParenLoc);
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BodyPattern = TuplePattern::create(Context, LParenLoc, BodyElts,
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RParenLoc);
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return Status;
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}
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/// Parse a pattern.
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/// pattern ::= pattern-atom
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/// pattern ::= pattern-atom ':' type-annotation
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ParserResult<Pattern> Parser::parsePattern() {
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// First, parse the pattern atom.
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ParserResult<Pattern> Result = parsePatternAtom();
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// Now parse an optional type annotation.
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if (consumeIf(tok::colon)) {
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if (Result.isNull()) {
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// Recover by creating AnyPattern.
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Result = makeParserErrorResult(new (Context) AnyPattern(PreviousLoc));
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}
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ParserResult<TypeRepr> Ty = parseTypeAnnotation();
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if (Ty.hasCodeCompletion())
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return makeParserCodeCompletionResult<Pattern>();
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if (Ty.isNull())
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Ty = makeParserResult(new (Context) ErrorTypeRepr(PreviousLoc));
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Result = makeParserResult(Result,
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new (Context) TypedPattern(Result.get(), Ty.get()));
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}
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return Result;
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}
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/// \brief Determine whether this token can start a pattern.
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bool Parser::isStartOfPattern(Token tok) {
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return tok.is(tok::kw__) || tok.is(tok::identifier) || tok.is(tok::l_paren);
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}
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/// \brief Determine whether this token can start a binding name, whether an
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/// identifier or the special discard-value binding '_'.
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bool Parser::isStartOfBindingName(Token tok) {
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return tok.is(tok::kw__) || tok.is(tok::identifier);
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}
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Pattern *Parser::createBindingFromPattern(SourceLoc loc,
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Identifier name) {
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VarDecl *var = new (Context) VarDecl(loc, name, Type(), CurDeclContext);
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return new (Context) NamedPattern(var);
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}
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/// Parse an identifier as a pattern.
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ParserResult<Pattern> Parser::parsePatternIdentifier() {
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SourceLoc loc = Tok.getLoc();
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if (consumeIf(tok::kw__)) {
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return makeParserResult(new (Context) AnyPattern(loc));
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}
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StringRef text = Tok.getText();
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if (consumeIf(tok::identifier)) {
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Identifier ident = Context.getIdentifier(text);
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return makeParserResult(createBindingFromPattern(loc, ident));
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}
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return nullptr;
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}
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/// Parse a pattern "atom", meaning the part that precedes the
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/// optional type annotation.
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///
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/// pattern-atom ::= identifier
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/// pattern-atom ::= '_'
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/// pattern-atom ::= pattern-tuple
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ParserResult<Pattern> Parser::parsePatternAtom() {
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switch (Tok.getKind()) {
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case tok::l_paren:
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return parsePatternTuple(/*AllowInitExpr*/false);
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case tok::identifier:
|
|
case tok::kw__:
|
|
return parsePatternIdentifier();
|
|
|
|
case tok::kw_super:
|
|
case tok::kw_metatype:
|
|
case tok::kw_self:
|
|
case tok::kw_Self:
|
|
case tok::kw_weak:
|
|
case tok::kw_unowned:
|
|
diagnose(Tok, diag::expected_pattern_is_keyword, Tok.getText());
|
|
consumeToken();
|
|
return nullptr;
|
|
|
|
case tok::code_complete:
|
|
// Just eat the token and return an error status, *not* the code completion
|
|
// status. We can not code complete anything here -- we expect an
|
|
// identifier.
|
|
consumeToken(tok::code_complete);
|
|
return nullptr;
|
|
|
|
default:
|
|
diagnose(Tok, diag::expected_pattern);
|
|
return nullptr;
|
|
}
|
|
}
|
|
|
|
std::pair<ParserStatus, Optional<TuplePatternElt>>
|
|
Parser::parsePatternTupleElement(bool allowInitExpr) {
|
|
// Parse the pattern.
|
|
ParserResult<Pattern> pattern = parsePattern();
|
|
if (pattern.hasCodeCompletion())
|
|
return std::make_pair(makeParserCodeCompletionStatus(), Nothing);
|
|
|
|
if (pattern.isNull())
|
|
return std::make_pair(makeParserError(), Nothing);
|
|
|
|
// Parse the optional initializer.
|
|
ExprHandle *init = nullptr;
|
|
if (Tok.is(tok::equal)) {
|
|
SourceLoc EqualLoc = consumeToken();
|
|
ParserResult<Expr> initR = parseExpr(diag::expected_init_value);
|
|
|
|
if (!allowInitExpr) {
|
|
auto inFlight = diagnose(EqualLoc, diag::non_func_decl_pattern_init);
|
|
if (initR.isNonNull())
|
|
inFlight.fixItRemove(SourceRange(EqualLoc, initR.get()->getEndLoc()));
|
|
}
|
|
|
|
// FIXME: Silently dropping initializer expressions where they aren't
|
|
// permitted.
|
|
if (allowInitExpr && initR.isNonNull())
|
|
init = ExprHandle::get(Context, initR.get());
|
|
}
|
|
|
|
return std::make_pair(
|
|
makeParserSuccess(),
|
|
TuplePatternElt(pattern.get(), init, getDefaultArgKind(init)));
|
|
}
|
|
|
|
/// Parse a tuple pattern.
|
|
///
|
|
/// pattern-tuple:
|
|
/// '(' pattern-tuple-body? ')'
|
|
/// pattern-tuple-body:
|
|
/// pattern-tuple-element (',' pattern-tuple-body)*
|
|
|
|
ParserResult<Pattern> Parser::parsePatternTuple(bool AllowInitExpr) {
|
|
SourceLoc RPLoc, LPLoc = consumeToken(tok::l_paren);
|
|
SourceLoc EllipsisLoc;
|
|
|
|
// Parse all the elements.
|
|
SmallVector<TuplePatternElt, 8> elts;
|
|
ParserStatus ListStatus = parseList(tok::r_paren, LPLoc, RPLoc,
|
|
tok::comma, /*OptionalSep=*/false,
|
|
diag::expected_rparen_tuple_pattern_list,
|
|
[&] () -> ParserStatus {
|
|
// Parse the pattern tuple element.
|
|
ParserStatus EltStatus;
|
|
Optional<TuplePatternElt> elt;
|
|
std::tie(EltStatus, elt) = parsePatternTupleElement(AllowInitExpr);
|
|
if (EltStatus.hasCodeCompletion())
|
|
return makeParserCodeCompletionStatus();
|
|
if (!elt)
|
|
return makeParserError();
|
|
|
|
// Add this element to the list.
|
|
elts.push_back(*elt);
|
|
|
|
// If there is no ellipsis, we're done with the element.
|
|
if (Tok.isNot(tok::ellipsis))
|
|
return makeParserSuccess();
|
|
SourceLoc ellLoc = consumeToken(tok::ellipsis);
|
|
|
|
// An element cannot have both an initializer and an ellipsis.
|
|
if (elt->getInit()) {
|
|
diagnose(ellLoc, diag::tuple_ellipsis_init)
|
|
.highlight(elt->getInit()->getExpr()->getSourceRange());
|
|
// Return success since the error was semantic, and the caller should not
|
|
// attempt recovery.
|
|
return makeParserSuccess();
|
|
}
|
|
|
|
// An ellipsis element shall have a specified element type.
|
|
// FIXME: This seems unnecessary.
|
|
TypedPattern *typedPattern = dyn_cast<TypedPattern>(elt->getPattern());
|
|
if (!typedPattern) {
|
|
diagnose(ellLoc, diag::untyped_pattern_ellipsis)
|
|
.highlight(elt->getPattern()->getSourceRange());
|
|
// Return success so that the caller does not attempt recovery -- it
|
|
// should have already happened when we were parsing the tuple element.
|
|
return makeParserSuccess();
|
|
}
|
|
|
|
// Variadic elements must come last.
|
|
// FIXME: Unnecessary restriction. It makes conversion more interesting,
|
|
// but is not complicated to support.
|
|
if (Tok.is(tok::r_paren)) {
|
|
EllipsisLoc = ellLoc;
|
|
} else {
|
|
diagnose(ellLoc, diag::ellipsis_pattern_not_at_end);
|
|
}
|
|
|
|
return makeParserSuccess();
|
|
});
|
|
|
|
return makeParserResult(ListStatus, TuplePattern::createSimple(
|
|
Context, LPLoc, elts, RPLoc,
|
|
EllipsisLoc.isValid(), EllipsisLoc));
|
|
}
|
|
|
|
ParserResult<Pattern> Parser::parseMatchingPattern() {
|
|
// TODO: Since we expect a pattern in this position, we should optimistically
|
|
// parse pattern nodes for productions shared by pattern and expression
|
|
// grammar. For short-term ease of initial implementation, we always go
|
|
// through the expr parser for ambiguious productions.
|
|
|
|
// Parse productions that can only be patterns.
|
|
// matching-pattern ::= matching-pattern-var
|
|
if (Tok.is(tok::kw_var)) {
|
|
return parseMatchingPatternVar();
|
|
}
|
|
// matching-pattern ::= 'is' type
|
|
if (Tok.is(tok::kw_is)) {
|
|
return parseMatchingPatternIsa();
|
|
}
|
|
|
|
// matching-pattern ::= expr
|
|
// Fall back to expression parsing for ambiguous forms. Name lookup will
|
|
// disambiguate.
|
|
ParserResult<Expr> subExpr = parseExpr(diag::expected_pattern);
|
|
if (subExpr.hasCodeCompletion())
|
|
return makeParserCodeCompletionStatus();
|
|
if (subExpr.isNull())
|
|
return nullptr;
|
|
|
|
return makeParserResult(new (Context) ExprPattern(subExpr.get()));
|
|
}
|
|
|
|
ParserResult<Pattern> Parser::parseMatchingPatternVar() {
|
|
// 'var' patterns shouldn't nest.
|
|
if (VarPatternDepth >= 1)
|
|
diagnose(Tok, diag::var_pattern_in_var);
|
|
|
|
VarPatternScope scope(*this);
|
|
|
|
SourceLoc varLoc = consumeToken(tok::kw_var);
|
|
ParserResult<Pattern> subPattern = parseMatchingPattern();
|
|
if (subPattern.isNull())
|
|
return nullptr;
|
|
return makeParserResult(new (Context) VarPattern(varLoc, subPattern.get()));
|
|
}
|
|
|
|
ParserResult<Pattern> Parser::parseMatchingPatternIsa() {
|
|
SourceLoc isLoc = consumeToken(tok::kw_is);
|
|
ParserResult<TypeRepr> castType = parseType();
|
|
if (castType.isNull() || castType.hasCodeCompletion())
|
|
return nullptr;
|
|
return makeParserResult(new (Context) IsaPattern(isLoc, castType.get()));
|
|
}
|
|
|
|
bool Parser::isOnlyStartOfMatchingPattern() {
|
|
return Tok.is(tok::kw_var)
|
|
|| Tok.is(tok::kw_is);
|
|
}
|