Compiler crash during typechecking involving callAsFunction + trailing closure + explicit init

[jamieQ]

Description

No response

Reproduction

struct S {
    func callAsFunction(_ c: () -> Void) {}
}

func f() {
    _ = S.init() {}
}

Stack dump

Unhandled coercion:
(struct_type decl="output.(file).S@<source>:1:8")
(tuple_type num_elements=0)

Please submit a bug report (https://swift.org/contributing/#reporting-bugs) and include the crash backtrace.
Stack dump:
0.	Program arguments: /cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend -frontend -S -primary-file <source> -target x86_64-unknown-linux-gnu -disable-objc-interop -no-color-diagnostics -Xcc -fno-color-diagnostics -g -debug-info-format=dwarf -dwarf-version=4 -empty-abi-descriptor -enable-anonymous-context-mangled-names -file-compilation-dir /app -Xllvm --x86-asm-syntax=intel -no-auto-bridging-header-chaining -module-name output -in-process-plugin-server-path /cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/lib/swift/host/libSwiftInProcPluginServer.so -plugin-path /cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/lib/swift/host/plugins -plugin-path /cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/local/lib/swift/host/plugins -o /app/output.s
1.	Swift version 6.3-dev (LLVM bff1370bd79c983, Swift 57cf4ce563f700b)
2.	Compiling with effective version 5.10
3.	While evaluating request TypeCheckPrimaryFileRequest(source_file "<source>")
4.	While evaluating request TypeCheckFunctionBodyRequest(output.(file).f()@<source>:5:6)
5.	While type-checking statement at [<source>:5:10 - line:7:1] RangeText="{
    _ = S.init() {}
"
6.	While type-checking expression at [<source>:6:5 - line:6:19] RangeText="_ = S.init() {"
7.	While type-checking-target starting at <source>:6:5
8.	Abort: function coerceToType at CSApply.cpp:7989
| 	Unhandled coercion:
| 	(struct_type decl="output.(file).S@<source>:1:8")
| 	(tuple_type num_elements=0)
 #0 0x000055aac31ae418 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend+0x8958418)
 #1 0x000055aac31abc05 llvm::sys::RunSignalHandlers() (/cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend+0x8955c05)
 #2 0x000055aac31af1c1 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
 #3 0x000079680f042520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x000079680f0969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #5 0x000079680f042476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #6 0x000079680f0287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #7 0x000055aabd40f802 (/cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend+0x2bb9802)
 #8 0x000055aabd40f8ec (/cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend+0x2bb98ec)
 #9 0x000055aabcae4b73 (anonymous namespace)::ExprRewriter::coerceToType(swift::Expr*, swift::Type, swift::constraints::ConstraintLocatorBuilder) CSApply.cpp:0:0
#10 0x000055aabcae6fa5 (anonymous namespace)::ExprWalker::walkToExprPost(swift::Expr*) CSApply.cpp:0:0
#11 0x000055aabcf38d96 (anonymous namespace)::Traversal::doIt(swift::Expr*) ASTWalker.cpp:0:0
#12 0x000055aabcf38ca3 swift::Expr::walk(swift::ASTWalker&) (/cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend+0x26e2ca3)
#13 0x000055aabcae017b (anonymous namespace)::ExprWalker::rewriteTarget(swift::constraints::SyntacticElementTarget) CSApply.cpp:0:0
#14 0x000055aabcadfaf8 swift::constraints::ConstraintSystem::applySolution(swift::constraints::Solution&, swift::constraints::SyntacticElementTarget) (/cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend+0x2289af8)
#15 0x000055aabc90234c swift::TypeChecker::typeCheckTarget(swift::constraints::SyntacticElementTarget&, swift::optionset::OptionSet<swift::TypeCheckExprFlags, unsigned int>, swift::DiagnosticTransaction*) (/cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend+0x20ac34c)
#16 0x000055aabc902131 swift::TypeChecker::typeCheckExpression(swift::constraints::SyntacticElementTarget&, swift::optionset::OptionSet<swift::TypeCheckExprFlags, unsigned int>, swift::DiagnosticTransaction*) (/cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend+0x20ac131)
#17 0x000055aabc902006 swift::TypeChecker::typeCheckExpression(swift::Expr*&, swift::DeclContext*, swift::constraints::ContextualTypeInfo, swift::optionset::OptionSet<swift::TypeCheckExprFlags, unsigned int>) (/cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend+0x20ac006)
#18 0x000055aabca0914b (anonymous namespace)::StmtChecker::typeCheckASTNode(swift::ASTNode&) TypeCheckStmt.cpp:0:0
#19 0x000055aabca0cfbd swift::ASTVisitor<(anonymous namespace)::StmtChecker, void, swift::Stmt*, void, void, void, void>::visit(swift::Stmt*) TypeCheckStmt.cpp:0:0
#20 0x000055aabca0afec bool (anonymous namespace)::StmtChecker::typeCheckStmt<swift::BraceStmt>(swift::BraceStmt*&) TypeCheckStmt.cpp:0:0
#21 0x000055aabca0a914 (anonymous namespace)::StmtChecker::typeCheckBody(swift::BraceStmt*&) TypeCheckStmt.cpp:0:0
#22 0x000055aabca0a544 swift::TypeCheckFunctionBodyRequest::evaluate(swift::Evaluator&, swift::AbstractFunctionDecl*) const (/cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend+0x21b4544)
#23 0x000055aabd08ebee swift::TypeCheckFunctionBodyRequest::OutputType swift::Evaluator::getResultUncached<swift::TypeCheckFunctionBodyRequest, swift::TypeCheckFunctionBodyRequest::OutputType swift::evaluateOrDefault<swift::TypeCheckFunctionBodyRequest>(swift::Evaluator&, swift::TypeCheckFunctionBodyRequest, swift::TypeCheckFunctionBodyRequest::OutputType)::'lambda'()>(swift::TypeCheckFunctionBodyRequest const&, swift::TypeCheckFunctionBodyRequest::OutputType swift::evaluateOrDefault<swift::TypeCheckFunctionBodyRequest>(swift::Evaluator&, swift::TypeCheckFunctionBodyRequest, swift::TypeCheckFunctionBodyRequest::OutputType)::'lambda'()) crtstuff.c:0:0
#24 0x000055aabcfe5df9 swift::AbstractFunctionDecl::getTypecheckedBody() const (/cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend+0x278fdf9)
#25 0x000055aabd16e118 swift::SourceFile::typeCheckDelayedFunctions() (/cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend+0x2918118)
#26 0x000055aabca7b75d swift::TypeCheckPrimaryFileRequest::evaluate(swift::Evaluator&, swift::SourceFile*) const (/cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend+0x222575d)
#27 0x000055aabca7fa4b swift::TypeCheckPrimaryFileRequest::OutputType swift::Evaluator::getResultUncached<swift::TypeCheckPrimaryFileRequest, swift::TypeCheckPrimaryFileRequest::OutputType swift::evaluateOrDefault<swift::TypeCheckPrimaryFileRequest>(swift::Evaluator&, swift::TypeCheckPrimaryFileRequest, swift::TypeCheckPrimaryFileRequest::OutputType)::'lambda'()>(swift::TypeCheckPrimaryFileRequest const&, swift::TypeCheckPrimaryFileRequest::OutputType swift::evaluateOrDefault<swift::TypeCheckPrimaryFileRequest>(swift::Evaluator&, swift::TypeCheckPrimaryFileRequest, swift::TypeCheckPrimaryFileRequest::OutputType)::'lambda'()) crtstuff.c:0:0
#28 0x000055aabca7b5a5 swift::performTypeChecking(swift::SourceFile&) (/cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend+0x22255a5)
#29 0x000055aabb5b8e59 bool llvm::function_ref<bool (swift::SourceFile&)>::callback_fn<swift::CompilerInstance::performSema()::$_10>(long, swift::SourceFile&) Frontend.cpp:0:0
#30 0x000055aabb5afada swift::CompilerInstance::forEachFileToTypeCheck(llvm::function_ref<bool (swift::SourceFile&)>) (/cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend+0xd59ada)
#31 0x000055aabb5af8cb swift::CompilerInstance::performSema() (/cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend+0xd598cb)
#32 0x000055aabb229372 withSemanticAnalysis(swift::CompilerInstance&, swift::FrontendObserver*, llvm::function_ref<bool (swift::CompilerInstance&)>, bool) FrontendTool.cpp:0:0
#33 0x000055aabb217f99 performCompile(swift::CompilerInstance&, int&, swift::FrontendObserver*, llvm::ArrayRef<char const*>) FrontendTool.cpp:0:0
#34 0x000055aabb214bfe swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) (/cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend+0x9bebfe)
#35 0x000055aabaf64aec swift::mainEntry(int, char const**) (/cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend+0x70eaec)
#36 0x000079680f029d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#37 0x000079680f029e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#38 0x000055aabaf639d5 _start (/cefs/fe/fe478d39bbcfde13719a3634_swift-nightly/usr/bin/swift-frontend+0x70d9d5)

Expected behavior

no crash

Environment

Swift version 6.3-dev (LLVM bff1370bd79c983, Swift 57cf4ce)
Target: x86_64-unknown-linux-gnu

Additional information

forum thread: https://forums.swift.org/t/why-can-initializer-parentheses-be-omitted-with-callasfunction-trailing-closure/83061/13

[jamieQ]

@xedin @naveen-seth IIUC this issue may have been erroneously closed due to the original link provided in the commit message differing from those in the edited GH PR message. the tests included in #85406 don't appear to cover this exact case, and the assertion failure/crash seems different than what was addressed in that PR.

[naveen-seth]

Hi, sorry about this!!
Out of habit, I thought it would be a squash + merge and that the PR message would be used. I should have paid closer attention there.
Is there anything I can do to remedy this (e.g., open a PR including both a revert and re-land so that the proper commit message and my mistake can be traced in the git blame)?
Again, my apologies.

[jamieQ]

@naveen-seth no worries at all, it's not a problem. i think we just need @xedin or someone with the right permissions to re-open this issue. that is, of course, if it is in fact still not fixed – perhaps you could confirm whether that's the case?

edit: and thanks for fixing that other bug! :)

[jamieQ]

thanks @xwu!