[Overview] Modernization code with clang-tidy

This issue is just to have an overview about clang-tidy modernizations.

Full list of clang-tidy checks.

Checks which redirect to another test are removed from following list.

Android:

• android-cloexec-accept (Nothing found)
• android-cloexec-accept4 (Nothing found)
• android-cloexec-creat (Nothing found)
• android-cloexec-dup (Nothing found)
• android-cloexec-epoll-create (Nothing found)
• android-cloexec-epoll-create1 (Nothing found)
• android-cloexec-fopen (discussion: #2748, PR: #2755, #3223)
• android-cloexec-inotify-init (Nothing found)
• android-cloexec-inotify-init1 (Nothing found)
• android-cloexec-memfd-create (Nothing found)
• android-cloexec-open (discussion: #2748, PR: #2755)
• android-cloexec-pipe (Nothing found)
• android-cloexec-pipe2 (Nothing found)
• android-cloexec-socket (Nothing found)
• android-comparison-in-temp-failure-retry (Nothing found)

Boost:

• boost-use-to-string (PR: #2785)

Bugprone:

• bugprone-argument-comment (Nothing found)
• bugprone-assert-side-effect (Nothing found)
• bugprone-bool-pointer-implicit-conversion
• bugprone-branch-clone (Nothing found)
• bugprone-copy-constructor-init
• bugprone-dangling-handle (Nothing found)
• bugprone-exception-escape
• bugprone-fold-init-type (Nothing found)
• bugprone-forward-declaration-namespace
• bugprone-forwarding-reference-overload (Nothing found)
• bugprone-inaccurate-erase (Nothing found)
• bugprone-incorrect-roundings
• bugprone-integer-division
• bugprone-lambda-function-name (Nothing found)
• bugprone-macro-parentheses
• bugprone-macro-repeated-side-effects (Nothing found)
• bugprone-misplaced-operator-in-strlen-in-alloc (Nothing found)
• bugprone-misplaced-widening-cast
• bugprone-move-forwarding-reference (Nothing found)
• bugprone-multiple-statement-macro
• bugprone-narrowing-conversions
• bugprone-parent-virtual-call
• bugprone-posix-return (Nothing found)
• bugprone-sizeof-container (Nothing found)
• bugprone-sizeof-expression
• bugprone-string-constructor (Nothing found)
• bugprone-string-integer-assignment (Nothing found)
• bugprone-string-literal-with-embedded-nul (Nothing found)
• bugprone-suspicious-enum-usage
• bugprone-suspicious-memset-usage (Nothing found)
• bugprone-suspicious-missing-comma (Nothing found)
• bugprone-suspicious-semicolon (Nothing found)
• bugprone-suspicious-string-compare
• bugprone-swapped-arguments (Nothing found)
• bugprone-terminating-continue (Nothing found)
• bugprone-throw-keyword-missing (Nothing found)
• bugprone-too-small-loop-variable (PR: #2829)
• bugprone-undefined-memory-manipulation
• bugprone-undelegated-constructor (Nothing found)
• bugprone-unhandled-self-assignment (Nothing found)
• bugprone-unused-raii (Nothing found)
• bugprone-unused-return-value (Nothing found)
• bugprone-use-after-move (Nothing found)
• bugprone-virtual-near-miss

Cert:

• cert-dcl21-cpp
• cert-dcl50-cpp
• cert-dcl58-cpp (Nothing found)
• cert-env33-c (Nothing found)
• cert-err34-c
• cert-err52-cpp
• cert-err58-cpp
• cert-err60-cpp
• cert-flp30-c
• cert-msc50-cpp
• cert-msc51-cpp
• cert-oop11-cp (Nothing found)

Clang-Analyzer:

• clang-analyzer-apiModeling.StdCLibraryFunctions (Nothing found)
• clang-analyzer-apiModeling.TrustNonnull (Nothing found)
• clang-analyzer-apiModeling.google.GTest (Nothing found)
• clang-analyzer-core.CallAndMessage
• clang-analyzer-core.DivideZero
• clang-analyzer-core.DynamicTypePropagation (Nothing found)
• clang-analyzer-core.NonNullParamChecker
• clang-analyzer-core.NonnilStringConstants (Nothing found)
• clang-analyzer-core.NullDereference
• clang-analyzer-core.StackAddressEscape (Nothing found)
• clang-analyzer-core.UndefinedBinaryOperatorResult (Nothing found)
• clang-analyzer-core.VLASize (Nothing found)
• clang-analyzer-core.builtin.BuiltinFunctions (Nothing found)
• clang-analyzer-core.builtin.NoReturnFunctions (Nothing found)
• clang-analyzer-core.uninitialized.ArraySubscript
• clang-analyzer-core.uninitialized.Assign
• clang-analyzer-core.uninitialized.Branch
• clang-analyzer-core.uninitialized.CapturedBlockVariable (Nothing found)
• clang-analyzer-core.uninitialized.UndefReturn
• clang-analyzer-cplusplus.InnerPointer (Nothing found)
• clang-analyzer-cplusplus.Move (Nothing found)
• clang-analyzer-cplusplus.NewDelete
• clang-analyzer-cplusplus.NewDeleteLeaks
• clang-analyzer-cplusplus.SelfAssignment (Nothing found)
• clang-analyzer-deadcode.DeadStores (PR: #3095)
• clang-analyzer-llvm.Conventions (check not released in a stable version of clang-tidy)
• clang-analyzer-nullability.NullPassedToNonnull (Nothing found)
• clang-analyzer-nullability.NullReturnedFromNonnull (Nothing found)
• clang-analyzer-nullability.NullableDereferenced (Nothing found)
• clang-analyzer-nullability.NullablePassedToNonnull (Nothing found)
• clang-analyzer-nullability.NullableReturnedFromNonnull (Nothing found)
• clang-analyzer-optin.cplusplus.VirtualCall
• clang-analyzer-optin.mpi.MPI-Checker (Nothing found)
• clang-analyzer-optin.osx.cocoa.localizability.EmptyLocalizationContextChecker (Nothing found)
• clang-analyzer-optin.osx.cocoa.localizability.NonLocalizedStringChecker (Nothing found)
• clang-analyzer-optin.performance.GCDAntipattern (Nothing found)
• clang-analyzer-optin.performance.Padding
• clang-analyzer-optin.portability.UnixAPI (Nothing found)
• clang-analyzer-osx.API (Nothing found)
• clang-analyzer-osx.NumberObjectConversion (Nothing found)
• clang-analyzer-osx.OSObjectRetainCount (Nothing found)
• clang-analyzer-osx.ObjCProperty (Nothing found)
• clang-analyzer-osx.SecKeychainAPI (Nothing found)
• clang-analyzer-osx.cocoa.AtSync (Nothing found)
• clang-analyzer-osx.cocoa.AutoreleaseWrite (Nothing found)
• clang-analyzer-osx.cocoa.ClassRelease (Nothing found)
• clang-analyzer-osx.cocoa.Dealloc (Nothing found)
• clang-analyzer-osx.cocoa.IncompatibleMethodTypes (Nothing found)
• clang-analyzer-osx.cocoa.Loops (Nothing found)
• clang-analyzer-osx.cocoa.MissingSuperCall (Nothing found)
• clang-analyzer-osx.cocoa.NSAutoreleasePool (Nothing found)
• clang-analyzer-osx.cocoa.NSError (Nothing found)
• clang-analyzer-osx.cocoa.NilArg (Nothing found)
• clang-analyzer-osx.cocoa.NonNilReturnValue (Nothing found)
• clang-analyzer-osx.cocoa.ObjCGenerics (Nothing found)
• clang-analyzer-osx.cocoa.RetainCount (Nothing found)
• clang-analyzer-osx.cocoa.RunLoopAutoreleaseLeak (Nothing found)
• clang-analyzer-osx.cocoa.SelfInit (Nothing found)
• clang-analyzer-osx.cocoa.SuperDealloc (Nothing found)
• clang-analyzer-osx.cocoa.UnusedIvars (Nothing found)
• clang-analyzer-osx.cocoa.VariadicMethodTypes (Nothing found)
• clang-analyzer-osx.coreFoundation.CFError (Nothing found)
• clang-analyzer-osx.coreFoundation.CFNumber (Nothing found)
• clang-analyzer-osx.coreFoundation.CFRetainRelease (Nothing found)
• clang-analyzer-osx.coreFoundation.containers.OutOfBounds (Nothing found)
• clang-analyzer-osx.coreFoundation.containers.PointerSizedValues (Nothing found)
• clang-analyzer-security.FloatLoopCounter
• clang-analyzer-security.insecureAPI.UncheckedReturn (Nothing found)
• clang-analyzer-security.insecureAPI.bcmp (Nothing found)
• clang-analyzer-security.insecureAPI.bcopy (Nothing found)
• clang-analyzer-security.insecureAPI.bzero (Nothing found)
• clang-analyzer-security.insecureAPI.getpw (Nothing found)
• clang-analyzer-security.insecureAPI.gets (Nothing found)
• clang-analyzer-security.insecureAPI.mkstemp (Nothing found)
• clang-analyzer-security.insecureAPI.mktemp (Nothing found)
• clang-analyzer-security.insecureAPI.rand (Nothing found)
• clang-analyzer-security.insecureAPI.strcpy
• clang-analyzer-security.insecureAPI.vfork (Nothing found)
• clang-analyzer-unix.API
• clang-analyzer-unix.Malloc
• clang-analyzer-unix.MallocSizeof (Nothing found)
• clang-analyzer-unix.MismatchedDeallocator
• clang-analyzer-unix.StdCLibraryFunctions (check not released in a stable version of clang-tidy)
• clang-analyzer-unix.Vfork (Nothing found)
• clang-analyzer-unix.cstring.BadSizeArg (Nothing found)
• clang-analyzer-unix.cstring.NullArg (Nothing found)
• clang-analyzer-valist.CopyToSelf (Nothing found)
• clang-analyzer-valist.Uninitialized (Nothing found)
• clang-analyzer-valist.Unterminated (Nothing found)

cppcoreguidelines

• cppcoreguidelines-avoid-goto
• cppcoreguidelines-interfaces-global-init (Nothing found)
• cppcoreguidelines-macro-usage
• cppcoreguidelines-narrowing-conversions
• cppcoreguidelines-no-malloc
• cppcoreguidelines-owning-memory
• cppcoreguidelines-pro-bounds-array-to-pointer-decay
• cppcoreguidelines-pro-bounds-constant-array-index
• cppcoreguidelines-pro-bounds-pointer-arithmetic
• cppcoreguidelines-pro-type-const-cast
• cppcoreguidelines-pro-type-cstyle-cast
• cppcoreguidelines-pro-type-member-init
• cppcoreguidelines-pro-type-reinterpret-cast
• cppcoreguidelines-pro-type-static-cast-downcast
• cppcoreguidelines-pro-type-union-access
• cppcoreguidelines-pro-type-vararg
• cppcoreguidelines-slicing
• cppcoreguidelines-special-member-functions

hicpp:

• hicpp-avoid-goto
• hicpp-exception-baseclass
• hicpp-multiway-paths-covered
• hicpp-no-assembler (Nothing found)
• hicpp-signed-bitwise

Misc:

• misc-definitions-in-headers
• misc-misplaced-const
• misc-new-delete-overloads (Nothing found)
• misc-non-copyable-objects (Nothing found)
• misc-non-private-member-variables-in-classes
• misc-redundant-expression
• misc-static-assert (Nothing found)
• misc-throw-by-value-catch-by-reference (Nothing found)
• misc-unconventional-assign-operator
• misc-uniqueptr-reset-release (Nothing found)
• misc-unused-alias-decls (Nothing found)
• misc-unused-parameters
• misc-unused-using-decls

Modernize:

• modernize-avoid-bind (Nothing found)
• modernize-avoid-c-arrays (PR: #4489)
• modernize-concat-nested-namespaces (requires C++17)
• modernize-deprecated-headers (PR: #2737)
• modernize-deprecated-ios-base-aliases
• modernize-loop-convert (PR: #2835, #2836, #2837, #2838, #2839, #2840, #2841, #2842, #2843, #2844, #2844, #2845, #2846, #2847, #2848, #2849, #2850, #2851, #2853, #2854, #2855, #2856, #2857, #2858, #2859, #2860)
• modernize-make-shared (Nothing found)
• modernize-make-unique (Nothing found)
• modernize-pass-by-value
• modernize-raw-string-literal (PR: #2789)
• modernize-redundant-void-arg (PR: #2780)
• modernize-replace-auto-ptr (Nothing found)
• modernize-replace-random-shuffle (PR: #3069)
• modernize-return-braced-init-list (PR: #3039)
• modernize-shrink-to-fit (Nothing found)
• modernize-unary-static-assert (requires C++17)
• modernize-use-auto (developer decision, so no auto transformation, see discussion in #2838)
• modernize-use-bool-literals (PR: #2793)
• modernize-use-default-member-init
• modernize-use-emplace (PR: #2784)
• modernize-use-equals-default (PR: #5386)
• modernize-use-equals-delete (PR: #2779)
• modernize-use-nodiscard (requires C++17)
• modernize-use-noexcept
• modernize-use-nullptr (PR: #3004, #3005, #3006, #3007, #3008, #3009, #3010, #3011, #3012, #3013, #3014, #3015, #3016, #3017, #3018, #3019, #3020, #3021, #3022, #3023, #3024, #3025, #3026, #3027, #3028, #3029)
• modernize-use-override (PR: #2728)
• modernize-use-trailing-return-type (check not released in a stable version of clang-tidy)
• modernize-use-transparent-functors (PR: #3224)
• modernize-use-uncaught-exceptions (requires C++17)
• modernize-use-using (PR: #3112, #3113, #3115, #3117, #3118, #3121, #3122, #3123, #3124, #3125, #3129, #3130, #3132, #3134, #3137, #3138, #3139)

MPI

• mpi-buffer-deref (Nothing found)
• mpi-type-mismatch (Nothing found)

OpenMP

• openmp-exception-escape (Nothing found)
• openmp-use-default-none (PR: #3524)

Performance

• performance-faster-string-find (PR: #2794)
• performance-for-range-copy (Nothing found)
• performance-implicit-conversion-in-loop (requires #3234)
• performance-inefficient-algorithm (Nothing found)
• performance-inefficient-string-concatenation (discussion: #3233)
• performance-inefficient-vector-operation (Nothing found)
• performance-move-const-arg (Nothing found)
• performance-move-constructor-init (Nothing found)
• performance-noexcept-move-constructor (Nothing found)
• performance-type-promotion-in-math-fn (PR: #3087)
• performance-unnecessary-copy-initialization
• performance-unnecessary-value-param (PR: #3232, #3253)

Readability:

• readability-avoid-const-params-in-decls
• readability-braces-around-statements
• readability-const-return-type
• readability-container-size-empty (PR: #3033)
• readability-delete-null-pointer (PR: #2990)
• readability-deleted-default (Nothing found)
• readability-else-after-return (PR: #3180, #3181, #3182, #3183, #3184, #3185, #3186)
• readability-function-size
• readability-identifier-naming (Nothing found)
• readability-implicit-bool-conversion
• readability-inconsistent-declaration-parameter-name
• readability-isolate-declaration
• readability-magic-numbers
• readability-make-member-function-const (PR: #3836)
• readability-misleading-indentation
• readability-misplaced-array-index (Nothing found)
• readability-named-parameter
• readability-non-const-parameter
• readability-redundant-control-flow
• readability-redundant-declaration (Nothing found)
• readability-redundant-function-ptr-dereference (Nothing found)
• readability-redundant-member-init (PR: #3070)
• readability-redundant-preprocessor (Nothing found)
• readability-redundant-smartptr-get (Nothing found)
• readability-redundant-string-cstr (PR: #3517)
• readability-redundant-string-init (PR: #2758)
• readability-simplify-boolean-expr (PR: #2790)
• readability-simplify-subscript-expr
• readability-static-accessed-through-instance (PR: #2776)
• readability-static-definition-in-anonymous-namespace (Nothing found)
• readability-string-compare (PR: #2986)
• readability-uniqueptr-delete-release (Nothing found)
• readability-uppercase-literal-suffix

Not relevant checks:

• abseil-*
• fuchsia-*
• google-*
• llvm-*
• objc-*
• portability-simd-intrinsics (experimental part of std)
• zircon-*

In case you see a modernization we could apply or can't apply, feel free to write it as comment. In case there is a modernization that needs discussion, open a new issue and write reference to it as comment, so I can add it to this list.

Start with the clang-tidy checks list linked in the issue and review the unchecked checks in the modernization overview. No source files or tests are named, so determine the relevant code and validation for one selected check before making changes; done would require completing that modernization and updating the checklist.