SwiftParser crashes on string with nested interpolation

[benlangmuir]

The parser is crashing on a string literal with nested interpolation. Found by running verify-round-trip on the source code for swift-argument-parser.

Reproduced with 38e3e4d.

$ cat str.swift
"text \(array.map({ "\($0)" }).joined(separator: ",")) text"

$ swift-parser-test verify-round-trip str.swift 
Swift/Collection.swift:711: Fatal error: Out of bounds: index >= endIndex
[1]    68834 trace trap  .build/debug/swift-parser-test verify-round-trip /tmp/str.swift

Checklist

• If possible, I've reproduced the issue using the main branch of this package.
• This issue hasn't been addressed in an existing GitHub issue.

Expected behavior

Should round-trip successfully.

Actual behavior

Crash

* thread #1, queue = 'com.apple.main-thread', stop reason = Fatal error: Out of bounds: index >= endIndex
  * frame #0: 0x00000001bc32a32c libswiftCore.dylib`::_swift_runtime_on_report(flags=1, message="Fatal error: Out of bounds: index >= endIndex", details=0x0000000000000000) at Errors.cpp:340:1 [opt]
    frame #1: 0x00000001bc32a330 libswiftCore.dylib`::_swift_reportToDebugger(flags=<unavailable>, message=<unavailable>, details=<unavailable>) at Errors.cpp:344:3 [opt] [artificial]
    frame #2: 0x00000001bc3bf8d8 libswiftCore.dylib`::_swift_stdlib_reportFatalErrorInFile(const unsigned char *, int, const unsigned char *, int, const unsigned char *, int, uint32_t, uint32_t) [inlined] logPrefixAndMessageToDebugger(prefix=<unavailable>, prefixLength=11, message="Out of bounds: index >= endIndex", messageLength=32) at Assert.cpp:39:3 [opt]
    frame #3: 0x00000001bc3bf88c libswiftCore.dylib`::_swift_stdlib_reportFatalErrorInFile(prefix=<unavailable>, prefixLength=11, message="Out of bounds: index >= endIndex", messageLength=32, file=<unavailable>, fileLength=<unavailable>, line=<unavailable>, flags=<unavailable>) at Assert.cpp:62:3 [opt]
    frame #4: 0x00000001bbfe31b0 libswiftCore.dylib`closure #1 in closure #1 in closure #1 in _assertionFailure(file=<unavailable>, prefix=<unavailable>, message=<unavailable>, line=<unavailable>, flags=<unavailable>) at AssertCommon.swift:91:9 [opt]
    frame #5: 0x00000001bbfe2ef4 libswiftCore.dylib`closure #1 in closure #1 in _assertionFailure(message=<unavailable>, file=<unavailable>, prefix=<unavailable>, line=<unavailable>, flags=1) at AssertCommon.swift:0 [opt]
    frame #6: 0x00000001bbfe2cec libswiftCore.dylib`closure #1 in _assertionFailure(prefix=<unavailable>, message=<unavailable>, file=<unavailable>, line=711, flags=1) at AssertCommon.swift:0 [opt]
    frame #7: 0x00000001bbfe284c libswiftCore.dylib`_assertionFailure(prefix=<unavailable>, message=<unavailable>, file=<unavailable>, line=711, flags=1) at AssertCommon.swift:85:10 [opt]
    frame #8: 0x00000001bc2c3e60 libswiftCore.dylib`specialized Collection._failEarlyRangeCheck(index=<unavailable>, bounds=<unavailable>) at Collection.swift:0 [opt]
    frame #9: 0x00000001002f3eb0 swift-parser-test`protocol witness for Collection._failEarlyRangeCheck(_:bounds:) in conformance SyntaxText at <compiler-generated>:0
    frame #10: 0x00000001bbfb7e34 libswiftCore.dylib`RandomAccessCollection<>.index(i=50, self=SwiftSyntax.SyntaxText @ 0x000000016fdfa878) at RandomAccessCollection.swift:296:5 [opt]
    frame #11: 0x00000001002f3f18 swift-parser-test`protocol witness for Collection.index(after:) in conformance SyntaxText at <compiler-generated>:0
    frame #12: 0x00000001bc176a08 libswiftCore.dylib`Slice.index(i=<unavailable>, self=<unavailable>) at Slice.swift:180:18 [opt]
    frame #13: 0x00000001bc034c08 libswiftCore.dylib`ClosedRange.relative<Bound>(collection=<unavailable>, self=7...50) at ClosedRange.swift:114:27 [opt]
    frame #14: 0x00000001bc0d91d8 libswiftCore.dylib`Collection.subscript.getter(r=<unavailable>, self=Swift.Slice<SwiftSyntax.SyntaxText> @ 0x000000016fdfa868) at Range.swift:934:19 [opt]
    frame #15: 0x00000001000f24dc swift-parser-test`Parser.parseStringLiteralSegments(text=Swift.Slice<SwiftSyntax.SyntaxText> @ 0x000000016fdfb010, closer=SwiftSyntax.RawTokenSyntax @ 0x000000016fdfb008, delimiter=SwiftSyntax.SyntaxText @ 0x000000016fdfaff8, self=SwiftParser.Parser @ 0x000000016fdfed50) at Expressions.swift:1167:58
    frame #16: 0x00000001000edff4 swift-parser-test`Parser.parseStringLiteral(self=SwiftParser.Parser @ 0x000000016fdfed50) at Expressions.swift:927:39
    frame #17: 0x00000001000e9154 swift-parser-test`Parser.parsePrimaryExpression(flavor=trailingClosure, self=SwiftParser.Parser @ 0x000000016fdfed50) at Expressions.swift:716:33
    frame #18: 0x00000001000e8ec8 swift-parser-test`Parser.parsePostfixExpression(flavor=trailingClosure, forDirective=false, self=SwiftParser.Parser @ 0x000000016fdfed50) at Expressions.swift:368:21
    frame #19: 0x00000001000e86e0 swift-parser-test`Parser.parseUnaryExpression(flavor=trailingClosure, forDirective=false, self=SwiftParser.Parser @ 0x000000016fdfed50) at Expressions.swift:339:19
    frame #20: 0x00000001000e7ea8 swift-parser-test`Parser.parseSequenceExpressionElement(flavor=trailingClosure, forDirective=false, self=SwiftParser.Parser @ 0x000000016fdfed50) at Expressions.swift:284:19
    frame #21: 0x00000001000e5c64 swift-parser-test`Parser.parseSequenceExpression(flavor=trailingClosure, forDirective=false, inVarOrLet=false, self=SwiftParser.Parser @ 0x000000016fdfed50) at Expressions.swift:94:24
    frame #22: 0x00000001000e59e8 swift-parser-test`Parser.parseExpression(flavor=trailingClosure, self=SwiftParser.Parser @ 0x000000016fdfed50) at Expressions.swift:40:31
    frame #23: 0x0000000100134ca0 swift-parser-test`Parser.parseItem(self=SwiftParser.Parser @ 0x000000016fdfed50) at TopLevel.swift:168:29
    frame #24: 0x0000000100133330 swift-parser-test`Parser.parseCodeBlockItem(self=SwiftParser.Parser @ 0x000000016fdfed50) at TopLevel.swift:117:21
    frame #25: 0x000000010013321c swift-parser-test`Parser.parseTopLevelCodeBlockItems(self=SwiftParser.Parser @ 0x000000016fdfed50) at TopLevel.swift:44:28
    frame #26: 0x0000000100132fe0 swift-parser-test`Parser.parseSourceFile(self=SwiftParser.Parser @ 0x000000016fdfed50) at TopLevel.swift:28:22
    frame #27: 0x000000010011e474 swift-parser-test`closure #1 in static Parser.parse(parser=SwiftParser.Parser @ 0x000000016fdfed50) at Parser.swift:45:35
    frame #28: 0x000000010011e664 swift-parser-test`partial apply for closure #1 in static Parser.parse(source:parseTransition:filenameForDiagnostics:languageVersion:enableBareSlashRegexLiteral:) at <compiler-generated>:0
    frame #29: 0x00000001bc10d8ac libswiftCore.dylib`withExtendedLifetime<T, Result>(x=<unavailable>, body=<unavailable>) at LifetimeManager.swift:27:14 [opt]
    frame #30: 0x000000010011dd14 swift-parser-test`static Parser.parse(source=60 values (0x600002600320), parseTransition=nil, filenameForDiagnostics="", languageVersion=nil, enableBareSlashRegexLiteral=nil, self=SwiftParser.Parser) at Parser.swift:44:12
    frame #31: 0x000000010011d9f0 swift-parser-test`closure #1 in static Parser.parse(buffer=60 values (0x600002600320), self=SwiftParser.Parser, parseTransition=nil, filenameForDiagnostics="", languageVersion=nil, enableBareSlashRegexLiteral=nil) at Parser.swift:26:18
    frame #32: 0x000000010011dacc swift-parser-test`partial apply for closure #1 in static Parser.parse(source:parseTransition:filenameForDiagnostics:languageVersion:enableBareSlashRegexLiteral:) at <compiler-generated>:0
    frame #33: 0x000000010011dfe0 swift-parser-test`String.withUTF8<R>(_:) at <compiler-generated>:0
    frame #34: 0x000000010011d81c swift-parser-test`static Parser.parse(source="\"text \\(array.map({ \"\\($0)\" }).joined(separator: \",\")) text\"", parseTransition=nil, filenameForDiagnostics="", languageVersion=nil, enableBareSlashRegexLiteral=nil, self=SwiftParser.Parser) at Parser.swift:25:23
    frame #35: 0x0000000100ded118 swift-parser-test`static VerifyRoundTrip.run(source="\"text \\(array.map({ \"\\($0)\" }).joined(separator: \",\")) text\"", swiftVersion=nil, enableBareSlashRegex=nil, self=swift_parser_test.VerifyRoundTrip) at swift-parser-test.swift:102:27
    frame #36: 0x0000000100decff4 swift-parser-test`VerifyRoundTrip.run(self=0x0000600002600480) at swift-parser-test.swift:98:14
    frame #37: 0x0000000100dee198 swift-parser-test`protocol witness for ParsableCommand.run() in conformance VerifyRoundTrip at <compiler-generated>:0
    frame #38: 0x000000010004166c swift-parser-test`static ParsableCommand.main(arguments=nil, self=swift_parser_test.SwiftParserTest) at ParsableCommand.swift:97:19
    frame #39: 0x0000000100041784 swift-parser-test`static ParsableCommand.main(self=swift_parser_test.SwiftParserTest) at ParsableCommand.swift:107:10
    frame #40: 0x0000000100deb344 swift-parser-test`static SwiftParserTest.$main(self=swift_parser_test.SwiftParserTest) at swift-parser-test.swift:56:1
    frame #41: 0x0000000100df8204 swift-parser-test`swift_parser_test_main at <compiler-generated>:0
    frame #42: 0x00000001020e508c dyld`start + 520

[ahoppen]

rdar://99025800