class Dat {
    let value1: Int
    let value2: Int
}
func test()  {
  (0..<1).map {
     Dat(value1: Int.random(0..<1), value2: $0)
  }

test.swift:1:7: error: class 'Dat' has no initializers
class Dat {
      ^
test.swift:2:9: note: stored property 'value1' without initial value prevents synthesized initializers
    let value1: Int
        ^
                    = 0
test.swift:3:9: note: stored property 'value2' without initial value prevents synthesized initializers
    let value2: Int
        ^
                    = 0
Assertion failed: (hasType(node) && "Expected type to have been set!"), function getType, file ConstraintSystem.h, line 2977.
Please submit a bug report (https://swift.org/contributing/#reporting-bugs) and include the project and the crash backtrace.
Stack dump:
0.  Program arguments: ../build/Ninja-ReleaseAssert/swift-macosx-x86_64/bin/swift -frontend -typecheck -sdk /Applications/Xcode/Sunriver/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.0.sdk test.swift
1.  Swift version 5.5-dev (LLVM c5470fe8cba4606, Swift 382809ad084cb18)
2.  
3.  While evaluating request TypeCheckSourceFileRequest(source_file "test.swift")
4.  While evaluating request TypeCheckFunctionBodyRequest(test.(file).test()@test.swift:5:6)
5.  While type-checking statement at [test.swift:5:14 - line:9:1] RangeText="{
  (0..<1).map {
     Dat(value1: Int.random(0..<1), value2: $0)
  }
"
6.  While type-checking expression at [test.swift:6:3 - line:8:3] RangeText="(0..<1).map {
     Dat(value1: Int.random(0..<1), value2: $0)
  "
Stack dump without symbol names (ensure you have llvm-symbolizer in your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point to it):
0  swift                    0x0000000106860fe7 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 39
1  swift                    0x000000010685fef8 llvm::sys::RunSignalHandlers() + 248
2  swift                    0x0000000106861846 SignalHandler(int) + 278
3  libsystem_platform.dylib 0x00007fff206e7d7d _sigtramp + 29
4  libsystem_platform.dylib 000000000000000000 _sigtramp + 18446603339972051616
5  libsystem_c.dylib        0x00007fff205f7411 abort + 120
6  libsystem_c.dylib        0x00007fff205f67e8 err + 0
7  swift                    0x0000000106c12553 swift::constraints::ConstraintSystem::getType(swift::ASTNode) const (.cold.2) + 35
8  swift                    0x00000001028393d9 swift::constraints::ConstraintSystem::getType(swift::ASTNode) const + 201
9  swift                    0x000000010289a352 (anonymous namespace)::ConstraintOptimizer::walkToExprPre(swift::Expr*) + 322
10 swift                    0x0000000102ce4073 swift::ASTVisitor<(anonymous namespace)::Traversal, swift::Expr*, swift::Stmt*, bool, swift::Pattern*, bool, void>::visit(swift::Expr*) + 2963
11 swift                    0x0000000102ce2eb9 swift::Expr::walk(swift::ASTWalker&) + 73
12 swift                    0x000000010288c6c2 swift::constraints::ConstraintSystem::optimizeConstraints(swift::Expr*) + 2082
13 swift                    0x00000001028bec3d swift::constraints::ConstraintSystem::performMemberLookup(swift::constraints::ConstraintKind, swift::DeclNameRef, swift::Type, swift::FunctionRefKind, swift::constraints::ConstraintLocator*, bool) + 2701
14 swift                    0x0000000102910ec8 swift::constraints::MissingMemberFailure::diagnoseAsError() + 3624
15 swift                    0x00000001028f890b swift::constraints::DefineMemberBasedOnUse::diagnoseForAmbiguity(llvm::ArrayRef<std::__1::pair<swift::constraints::Solution const*, swift::constraints::ConstraintFix const*> >) const + 331
16 swift                    0x000000010295bf30 swift::constraints::ConstraintSystem::diagnoseAmbiguityWithFixes(llvm::SmallVectorImpl<swift::constraints::Solution>&) + 12576
17 swift                    0x0000000102958928 swift::constraints::ConstraintSystem::salvage() + 232
18 swift                    0x00000001028dcb61 swift::constraints::ConstraintSystem::solve(swift::constraints::SolutionApplicationTarget&, swift::FreeTypeVariableBinding) + 529
19 swift                    0x0000000102a09cb0 swift::TypeChecker::typeCheckExpression(swift::constraints::SolutionApplicationTarget&, swift::OptionSet<swift::TypeCheckExprFlags, unsigned int>) + 480
20 swift                    0x0000000102a09a4e swift::TypeChecker::typeCheckExpression(swift::Expr*&, swift::DeclContext*, swift::constraints::ContextualTypeInfo, swift::OptionSet<swift::TypeCheckExprFlags, unsigned int>) + 78
21 swift                    0x0000000102ac1cf5 (anonymous namespace)::StmtChecker::typeCheckASTNode(swift::ASTNode&) + 229
22 swift                    0x0000000102ac3cac swift::ASTVisitor<(anonymous namespace)::StmtChecker, void, swift::Stmt*, void, void, void, void>::visit(swift::Stmt*) + 284
23 swift                    0x0000000102ac2f40 bool (anonymous namespace)::StmtChecker::typeCheckStmt<swift::BraceStmt>(swift::BraceStmt*&) + 128
24 swift                    0x0000000102ac2474 swift::TypeCheckFunctionBodyRequest::evaluate(swift::Evaluator&, swift::AbstractFunctionDecl*) const + 916
25 swift                    0x0000000102ddc4bf llvm::Expected<swift::TypeCheckFunctionBodyRequest::OutputType> swift::Evaluator::getResultUncached<swift::TypeCheckFunctionBodyRequest>(swift::TypeCheckFunctionBodyRequest const&) + 415
26 swift                    0x0000000102ddc25b llvm::Expected<swift::TypeCheckFunctionBodyRequest::OutputType> swift::Evaluator::getResultCached<swift::TypeCheckFunctionBodyRequest, (void*)0>(swift::TypeCheckFunctionBodyRequest const&) + 107
27 swift                    0x0000000102d3c1e3 swift::TypeCheckFunctionBodyRequest::OutputType swift::evaluateOrDefault<swift::TypeCheckFunctionBodyRequest>(swift::Evaluator&, swift::TypeCheckFunctionBodyRequest, swift::TypeCheckFunctionBodyRequest::OutputType) + 35
28 swift                    0x0000000102af5858 swift::TypeCheckSourceFileRequest::evaluate(swift::Evaluator&, swift::SourceFile*) const + 328
29 swift                    0x0000000102af6760 llvm::Expected<swift::TypeCheckSourceFileRequest::OutputType> swift::Evaluator::getResultUncached<swift::TypeCheckSourceFileRequest>(swift::TypeCheckSourceFileRequest const&) + 416
30 swift                    0x0000000102af6514 llvm::Expected<swift::TypeCheckSourceFileRequest::OutputType> swift::Evaluator::getResultCached<swift::TypeCheckSourceFileRequest, (void*)0>(swift::TypeCheckSourceFileRequest const&) + 100
31 swift                    0x0000000102af561f swift::TypeCheckSourceFileRequest::OutputType swift::evaluateOrDefault<swift::TypeCheckSourceFileRequest>(swift::Evaluator&, swift::TypeCheckSourceFileRequest, swift::TypeCheckSourceFileRequest::OutputType) + 31
32 swift                    0x0000000101dedb6e swift::CompilerInstance::forEachFileToTypeCheck(llvm::function_ref<void (swift::SourceFile&)>) + 158
33 swift                    0x0000000101deda1a swift::CompilerInstance::performSema() + 74
34 swift                    0x0000000101cb7783 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 5699
35 swift                    0x0000000101c61ac3 swift::mainEntry(int, char const**) + 499
36 libdyld.dylib            0x00007fff206bdf3d start + 1
37 libdyld.dylib            0x0000000000000006 start + 18446603339972223178

class Dat {
    let value1: Int
    let value2: Int
}
func test()  {
  Dat(value1: Int.random(0..<1), value2: 1) 
}