// RUN: %swift-frontend -typecheck %s

public extension Array {
    func chunked(into size: Int) -> [[Element]] {
        return stride(from: 0, to: count, by: size).map { elt in
            self[elt


public extension Array where Element == Item {
    mutating func toggle(item: Item) -> Bool {
        _ = contains(item)
    }
}

Assertion failed: ((env || !type->hasTypeParameter()) && "no generic environment provided for type with type parameters"), function mapTypeIntoContext, file GenericEnvironment.cpp, line 91.
Please submit a bug report (https://swift.org/contributing/#reporting-bugs) and include the project and the crash backtrace.
Stack dump:
0.  Program arguments: /Users/alex/swift-src/mbuild/Release+Asserts/swift-macosx-x86_64/bin/swift-frontend -module-cache-path /Users/alex/swift-src/mbuild/Release+Asserts/swift-macosx-x86_64/swift-test-results/x86_64-apple-macosx10.9/clang-module-cache -disable-objc-attr-requires-foundation-module -swift-version 4 -define-availability "SwiftStdlib 5.5:macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0-frontend" -typecheck /Users/alex/swift-src/swift/test/Array.swift
1.  Swift version 5.6-dev (LLVM 3f1736177ffe15c, Swift 14be9e71fa4a958)
2.  Compiling with effective version 4.1.50
3.  While evaluating request TypeCheckSourceFileRequest(source_file "/Users/alex/swift-src/swift/test/Array.swift")
4.  While evaluating request TypeCheckFunctionBodyRequest(Array.(file).Array extension.chunked(into:).explicit closure discriminator=0.Array extension.toggle(item:)@/Users/alex/swift-src/swift/test/Array.swift:10:19)
5.  While type-checking statement at [/Users/alex/swift-src/swift/test/Array.swift:10:46 - line:12:5] RangeText="{
        _ = contains(item)
    "
6.  While type-checking expression at [/Users/alex/swift-src/swift/test/Array.swift:11:9 - line:11:26] RangeText="_ = contains(item"
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-frontend           0x00000001128c5d07 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 39
1  swift-frontend           0x00000001128c4c28 llvm::sys::RunSignalHandlers() + 248
2  swift-frontend           0x00000001128c6350 SignalHandler(int) + 288
3  libsystem_platform.dylib 0x00007ff81cd17e2d _sigtramp + 29
4  libsystem_platform.dylib 000000000000000000 _sigtramp + 18446603370097443312
5  libsystem_c.dylib        0x00007ff81cc4ed10 abort + 123
6  libsystem_c.dylib        0x00007ff81cc4e0be err + 0
7  swift-frontend           0x0000000112dfc161 swift::GenericEnvironment::mapTypeIntoContext(swift::GenericEnvironment*, swift::Type) (.cold.2) + 33
8  swift-frontend           0x000000010ec138f2 swift::GenericEnvironment::mapTypeIntoContext(swift::GenericEnvironment*, swift::Type) + 98
9  swift-frontend           0x000000010e856ce1 swift::TypeChecker::lookupUnqualified(swift::DeclContext*, swift::DeclNameRef, swift::SourceLoc, swift::OptionSet<swift::NameLookupFlags, unsigned int>) + 657
10 swift-frontend           0x000000010e79a92e swift::TypeChecker::resolveDeclRefExpr(swift::UnresolvedDeclRefExpr*, swift::DeclContext*, bool) + 1134
11 swift-frontend           0x000000010e79e662 (anonymous namespace)::PreCheckExpression::walkToExprPre(swift::Expr*) + 1154
12 swift-frontend           0x000000010eac1bb9 swift::ASTVisitor<(anonymous namespace)::Traversal, swift::Expr*, swift::Stmt*, bool, swift::Pattern*, bool, void>::visit(swift::Expr*) + 281
13 swift-frontend           0x000000010eac206a swift::ASTVisitor<(anonymous namespace)::Traversal, swift::Expr*, swift::Stmt*, bool, swift::Pattern*, bool, void>::visit(swift::Expr*) + 1482
14 swift-frontend           0x000000010eac12f9 swift::Expr::walk(swift::ASTWalker&) + 73
15 swift-frontend           0x000000010e79d9da swift::constraints::ConstraintSystem::preCheckExpression(swift::Expr*&, swift::DeclContext*, bool) + 250
16 swift-frontend           0x000000010e7f4624 swift::TypeChecker::typeCheckExpression(swift::constraints::SolutionApplicationTarget&, swift::OptionSet<swift::TypeCheckExprFlags, unsigned int>) + 196
17 swift-frontend           0x000000010e7f44de swift::TypeChecker::typeCheckExpression(swift::Expr*&, swift::DeclContext*, swift::constraints::ContextualTypeInfo, swift::OptionSet<swift::TypeCheckExprFlags, unsigned int>) + 78
18 swift-frontend           0x000000010e8ad285 (anonymous namespace)::StmtChecker::typeCheckASTNode(swift::ASTNode&) + 229
19 swift-frontend           0x000000010e8af25c swift::ASTVisitor<(anonymous namespace)::StmtChecker, void, swift::Stmt*, void, void, void, void>::visit(swift::Stmt*) + 124
20 swift-frontend           0x000000010e8ae4b3 bool (anonymous namespace)::StmtChecker::typeCheckStmt<swift::BraceStmt>(swift::BraceStmt*&) + 131
21 swift-frontend           0x000000010e8ada19 swift::TypeCheckFunctionBodyRequest::evaluate(swift::Evaluator&, swift::AbstractFunctionDecl*) const + 937
22 swift-frontend           0x000000010ebbc19f llvm::Expected<swift::TypeCheckFunctionBodyRequest::OutputType> swift::Evaluator::getResultUncached<swift::TypeCheckFunctionBodyRequest>(swift::TypeCheckFunctionBodyRequest const&) + 415
23 swift-frontend           0x000000010ebbbf3b llvm::Expected<swift::TypeCheckFunctionBodyRequest::OutputType> swift::Evaluator::getResultCached<swift::TypeCheckFunctionBodyRequest, (void*)0>(swift::TypeCheckFunctionBodyRequest const&) + 107
24 swift-frontend           0x000000010eb1c513 swift::TypeCheckFunctionBodyRequest::OutputType swift::evaluateOrDefault<swift::TypeCheckFunctionBodyRequest>(swift::Evaluator&, swift::TypeCheckFunctionBodyRequest, swift::TypeCheckFunctionBodyRequest::OutputType) + 35
25 swift-frontend           0x000000010e8dd558 swift::TypeCheckSourceFileRequest::evaluate(swift::Evaluator&, swift::SourceFile*) const + 328
26 swift-frontend           0x000000010e8df280 llvm::Expected<swift::TypeCheckSourceFileRequest::OutputType> swift::Evaluator::getResultUncached<swift::TypeCheckSourceFileRequest>(swift::TypeCheckSourceFileRequest const&) + 416
27 swift-frontend           0x000000010e8df034 llvm::Expected<swift::TypeCheckSourceFileRequest::OutputType> swift::Evaluator::getResultCached<swift::TypeCheckSourceFileRequest, (void*)0>(swift::TypeCheckSourceFileRequest const&) + 100
28 swift-frontend           0x000000010e8dd31f swift::TypeCheckSourceFileRequest::OutputType swift::evaluateOrDefault<swift::TypeCheckSourceFileRequest>(swift::Evaluator&, swift::TypeCheckSourceFileRequest, swift::TypeCheckSourceFileRequest::OutputType) + 31
29 swift-frontend           0x000000010dbad89e swift::CompilerInstance::forEachFileToTypeCheck(llvm::function_ref<void (swift::SourceFile&)>) + 158
30 swift-frontend           0x000000010dbad74a swift::CompilerInstance::performSema() + 74
31 swift-frontend           0x000000010da3f9b0 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 5984
32 swift-frontend           0x000000010da08a17 swift::mainEntry(int, char const**) + 503
33 dyld                     0x00000001283034fe start + 462
34 dyld                     000000000000000000 start + 18446744068740336848
35 swift-frontend           0x000000010d9e8000 __dso_handle + 0
/Users/alex/swift-src/mbuild/Release+Asserts/swift-macosx-x86_64/test-macosx-x86_64/Output/Array.swift.script: line 1: 49432 Abort trap: 6           '/Users/alex/swift-src/mbuild/Release+Asserts/swift-macosx-x86_64/bin/swift-frontend' -module-cache-path /Users/alex/swift-src/mbuild/Release+Asserts/swift-macosx-x86_64/swift-test-results/x86_64-apple-macosx10.9/clang-module-cache -disable-objc-attr-requires-foundation-module -swift-version 4 -define-availability 'SwiftStdlib 5.5:macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0'-frontend -typecheck /Users/alex/swift-src/swift/test/Array.swift