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[SE-0276] Syntax and Parse updates #30811

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f4c12ce
[SE-0276] Implement multi-pattern catch syntax
owenv Apr 4, 2020
50d97a2
[SE-0276] Temporary updates to support multi-pattern catch parsing wi…
owenv Apr 4, 2020
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2 changes: 2 additions & 0 deletions include/swift/AST/DiagnosticsParse.def
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Expand Up @@ -1086,6 +1086,8 @@ ERROR(expected_catch_where_expr,PointsToFirstBadToken,
ERROR(docatch_not_trycatch,PointsToFirstBadToken,
"the 'do' keyword is used to specify a 'catch' region",
())
ERROR(multi_pattern_catch_unsupported,none,"'catch' statements do not yet "
"support multiple patterns", ())

// C-Style For Stmt
ERROR(c_style_for_stmt_removed,none,
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74 changes: 64 additions & 10 deletions lib/Parse/ParseStmt.cpp
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Expand Up @@ -1981,15 +1981,63 @@ ParserResult<CatchStmt> Parser::parseStmtCatch() {
SourceLoc catchLoc = consumeToken(tok::kw_catch);

SmallVector<VarDecl*, 4> boundDecls;

ParserStatus status;
GuardedPattern pattern;
parseGuardedPattern(*this, pattern, status, boundDecls,
GuardedPatternContext::Catch, /* isFirst */ true);
if (status.hasCodeCompletion()) {
return makeParserCodeCompletionResult<CatchStmt>();
Optional<MutableArrayRef<VarDecl *>> caseBodyDecls;
SmallVector<CaseLabelItem, 1> caseLabelItems;

{
SyntaxParsingContext ListContext(SyntaxContext, SyntaxKind::CatchItemList);
bool isFirst = true;
while (true) {
SyntaxParsingContext ItemContext(SyntaxContext, SyntaxKind::CatchItem);
GuardedPattern PatternResult;
parseGuardedPattern(*this, PatternResult, status, boundDecls,
GuardedPatternContext::Catch, isFirst);
if (status.hasCodeCompletion()) {
return makeParserCodeCompletionResult<CatchStmt>();
}
caseLabelItems.emplace_back(PatternResult.ThePattern,
PatternResult.WhereLoc, PatternResult.Guard);
isFirst = false;
if (!consumeIf(tok::comma))
break;
}

// Grab the first case label item pattern and use it to initialize the case
// body var decls.
// TODO: Uncomment when AST supports multi-pattern catches
// SmallVector<VarDecl *, 4> tmp;
// caseLabelItems.front().getPattern()->collectVariables(tmp);
// auto Result = Context.AllocateUninitialized<VarDecl *>(tmp.size());
// for (unsigned i : indices(tmp)) {
// auto *vOld = tmp[i];
// auto *vNew = new (Context) VarDecl(
// /*IsStatic*/ false, vOld->getIntroducer(), false
// /*IsCaptureList*/, vOld->getNameLoc(), vOld->getName(),
// vOld->getDeclContext());
// vNew->setHasNonPatternBindingInit();
// vNew->setImplicit();
// Result[i] = vNew;
// }
// caseBodyDecls.emplace(Result);
}

// Add a scope so that the parser can find our body bound decls if it emits
// optimized accesses.
// TODO: Uncomment when AST supports multi-pattern catches
// Optional<Scope> BodyScope;
// if (caseBodyDecls) {
// BodyScope.emplace(this, ScopeKind::CatchVars);
// for (auto *v : *caseBodyDecls) {
// setLocalDiscriminator(v);
// // If we had any bad redefinitions, we already diagnosed them against
// the
// // first case label item.
// if (v->hasName())
// addToScope(v, false /*diagnoseRedefinitions*/);
// }
//}

auto bodyResult = parseBraceItemList(diag::expected_lbrace_after_catch);
status |= bodyResult;
if (bodyResult.isNull()) {
Expand All @@ -1998,10 +2046,16 @@ ParserResult<CatchStmt> Parser::parseStmtCatch() {
/*implicit=*/ true));
}

auto result =
new (Context) CatchStmt(catchLoc, pattern.ThePattern, pattern.WhereLoc,
pattern.Guard, bodyResult.get());
return makeParserResult(status, result);
auto result = new (Context) CatchStmt(
catchLoc, caseLabelItems[0].getPattern(), caseLabelItems[0].getWhereLoc(),
caseLabelItems[0].getGuardExpr(), bodyResult.get());

if (caseLabelItems.size() > 1) {
diagnose(catchLoc, diag::multi_pattern_catch_unsupported);
return makeParserErrorResult(result);
} else {
return makeParserResult(status, result);
}
}

static bool isStmtForCStyle(Parser &P) {
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7 changes: 7 additions & 0 deletions test/Parse/errors.swift
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Expand Up @@ -55,6 +55,13 @@ func one() {
#endif
} catch { // don't warn, #if code should be scanned.
}

do {
throw opaque_error()
} catch MSV.Foo, MSV.CarriesInt(let num) { // expected-error {{'num' must be bound in every pattern}}
// expected-error@-1 {{'catch' statements do not yet support multiple patterns}}
} catch {
}
}

func takesAutoclosure(_ fn : @autoclosure () -> Int) {}
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9 changes: 5 additions & 4 deletions test/Syntax/Outputs/round_trip_parse_gen.swift.withkinds
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Expand Up @@ -328,10 +328,11 @@ do <CodeBlock>{<SwitchStmt>

func statementTests<FunctionSignature><ParameterClause>() </ParameterClause></FunctionSignature><CodeBlock>{<DoStmt>
do <CodeBlock>{
} </CodeBlock><CatchClause>catch <ExpressionPattern><TupleExpr>(<TupleExprElement><UnresolvedPatternExpr><ValueBindingPattern>var <IdentifierPattern>x</IdentifierPattern></ValueBindingPattern></UnresolvedPatternExpr>, </TupleExprElement><TupleExprElement><UnresolvedPatternExpr><ValueBindingPattern>let <IdentifierPattern>y</IdentifierPattern></ValueBindingPattern></UnresolvedPatternExpr></TupleExprElement>) </TupleExpr></ExpressionPattern><CodeBlock>{
} </CodeBlock></CatchClause><CatchClause>catch <WhereClause>where <BooleanLiteralExpr>false </BooleanLiteralExpr></WhereClause><CodeBlock>{
} </CodeBlock></CatchClause><CatchClause>catch <ValueBindingPattern>let <IdentifierPattern>e </IdentifierPattern></ValueBindingPattern><WhereClause>where <SequenceExpr><MemberAccessExpr><IdentifierExpr>e</IdentifierExpr>.foo </MemberAccessExpr><BinaryOperatorExpr>== </BinaryOperatorExpr><IdentifierExpr>bar </IdentifierExpr></SequenceExpr></WhereClause><CodeBlock>{
} </CodeBlock></CatchClause><CatchClause>catch <CodeBlock>{
} </CodeBlock><CatchClause>catch <CatchItem><ExpressionPattern><TupleExpr>(<TupleExprElement><UnresolvedPatternExpr><ValueBindingPattern>var <IdentifierPattern>x</IdentifierPattern></ValueBindingPattern></UnresolvedPatternExpr>, </TupleExprElement><TupleExprElement><UnresolvedPatternExpr><ValueBindingPattern>let <IdentifierPattern>y</IdentifierPattern></ValueBindingPattern></UnresolvedPatternExpr></TupleExprElement>) </TupleExpr></ExpressionPattern></CatchItem><CodeBlock>{
} </CodeBlock></CatchClause><CatchClause>catch <CatchItem><WhereClause>where <BooleanLiteralExpr>false </BooleanLiteralExpr></WhereClause></CatchItem><CodeBlock>{
} </CodeBlock></CatchClause><CatchClause>catch <CatchItem><ValueBindingPattern>let <IdentifierPattern>e </IdentifierPattern></ValueBindingPattern><WhereClause>where <SequenceExpr><MemberAccessExpr><IdentifierExpr>e</IdentifierExpr>.foo </MemberAccessExpr><BinaryOperatorExpr>== </BinaryOperatorExpr><IdentifierExpr>bar </IdentifierExpr></SequenceExpr></WhereClause></CatchItem><CodeBlock>{
} </CodeBlock></CatchClause><CatchClause>catch <CatchItem><ExpressionPattern><FunctionCallExpr><MemberAccessExpr>.a</MemberAccessExpr>(<TupleExprElement><UnresolvedPatternExpr><ValueBindingPattern>let <IdentifierPattern>a</IdentifierPattern></ValueBindingPattern></UnresolvedPatternExpr></TupleExprElement>)</FunctionCallExpr></ExpressionPattern>, </CatchItem><CatchItem><ExpressionPattern><FunctionCallExpr><MemberAccessExpr>.b</MemberAccessExpr>(<TupleExprElement><UnresolvedPatternExpr><ValueBindingPattern>let <IdentifierPattern>b</IdentifierPattern></ValueBindingPattern></UnresolvedPatternExpr></TupleExprElement>) </FunctionCallExpr></ExpressionPattern><WhereClause>where <SequenceExpr><IdentifierExpr>b </IdentifierExpr><BinaryOperatorExpr>== </BinaryOperatorExpr><StringLiteralExpr>"<StringSegment></StringSegment>" </StringLiteralExpr></SequenceExpr></WhereClause></CatchItem><CodeBlock>{
} </CodeBlock></CatchClause><CatchClause>catch <CatchItem></CatchItem><CodeBlock>{
}</CodeBlock></CatchClause></DoStmt><RepeatWhileStmt>
repeat <CodeBlock>{ } </CodeBlock>while <BooleanLiteralExpr>true</BooleanLiteralExpr></RepeatWhileStmt><RepeatWhileStmt>
LABEL: repeat <CodeBlock>{ } </CodeBlock>while <BooleanLiteralExpr>false</BooleanLiteralExpr></RepeatWhileStmt><WhileStmt>
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1 change: 1 addition & 0 deletions test/Syntax/round_trip_parse_gen.swift
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Expand Up @@ -331,6 +331,7 @@ func statementTests() {
} catch (var x, let y) {
} catch where false {
} catch let e where e.foo == bar {
} catch .a(let a), .b(let b) where b == "" {
} catch {
}
repeat { } while true
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8 changes: 8 additions & 0 deletions test/stmt/errors.swift
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Expand Up @@ -97,6 +97,14 @@ class eight {
}()
}

func multiPattern() {
do {
throw opaque_error() // expected-error {{error is not handled because the enclosing catch is not exhaustive}}
} catch MSV.Foo, _ { // expected-error {{'catch' statements do not yet support multiple patterns}}
_ = e
}
}

protocol ThrowingProto {
func foo() throws
static func bar() throws
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2 changes: 2 additions & 0 deletions utils/gyb_syntax_support/NodeSerializationCodes.py
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Expand Up @@ -244,6 +244,8 @@
'PoundFilePathExpr': 240,
'DerivativeRegistrationAttributeArguments': 241,
'QualifiedDeclName': 242,
'CatchItem': 243,
'CatchItemList': 244,
}


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24 changes: 19 additions & 5 deletions utils/gyb_syntax_support/StmtNodes.py
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Expand Up @@ -177,6 +177,10 @@
Node('CaseItemList', kind='SyntaxCollection',
element='CaseItem'),

# catch-item-list -> catch-item catch-item-list?
Node('CatchItemList', kind='SyntaxCollection',
element='CatchItem'),

# condition -> expression
# | availability-condition
# | case-condition
Expand Down Expand Up @@ -315,6 +319,17 @@
is_optional=True),
]),

# catch-item -> pattern? where-clause? ','?
Node('CatchItem', kind='Syntax',
traits=['WithTrailingComma'],
children=[
Child('Pattern', kind='Pattern', is_optional=True),
Child('WhereClause', kind='WhereClause',
is_optional=True),
Child('TrailingComma', kind='CommaToken',
is_optional=True),
]),

# switch-case-label -> 'case' case-item-list ':'
Node('SwitchCaseLabel', kind='Syntax',
children=[
Expand All @@ -324,14 +339,13 @@
Child('Colon', kind='ColonToken'),
]),

# catch-clause 'catch' pattern? where-clause? code-block
# catch-clause 'catch' case-item-list? code-block
Node('CatchClause', kind='Syntax',
traits=['WithCodeBlock'],
children=[
Child('CatchKeyword', kind='CatchToken'),
Child('Pattern', kind='Pattern',
is_optional=True),
Child('WhereClause', kind='WhereClause',
is_optional=True),
Child('CatchItems', kind='CatchItemList',
collection_element_name='CatchItem', is_optional=True),
Child('Body', kind='CodeBlock'),
]),

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