xref: /llvm-project/clang-tools-extra/test/clang-tidy/checkers/modernize/loop-convert-reverse.cpp (revision 6a1f8ef8a7aaefea80ef0bc7c6c462a96215b50e) 
1 // RUN: %check_clang_tidy -std=c++20 -check-suffixes=,RANGES %s modernize-loop-convert %t
2 
3 // RUN: %check_clang_tidy -check-suffixes=,CUSTOM,CUSTOM-NO-SYS %s modernize-loop-convert %t -- \
4 // RUN:   -config="{CheckOptions: [ \
5 // RUN:   {key: modernize-loop-convert.MakeReverseRangeFunction, value: 'llvm::reverse'}, \
6 // RUN:   {key: modernize-loop-convert.MakeReverseRangeHeader, value: 'llvm/ADT/STLExtras.h'}]}"
7 
8 // RUN: %check_clang_tidy -check-suffixes=,CUSTOM,CUSTOM-SYS %s modernize-loop-convert %t -- \
9 // RUN:   -config="{CheckOptions: [ \
10 // RUN:   {key: modernize-loop-convert.MakeReverseRangeFunction, value: 'llvm::reverse'}, \
11 // RUN:   {key: modernize-loop-convert.MakeReverseRangeHeader, value: '<llvm/ADT/STLExtras.h>'}]}"
12 
13 // RUN: %check_clang_tidy -check-suffixes=,CUSTOM,CUSTOM-NO-HEADER %s modernize-loop-convert %t -- \
14 // RUN:   -config="{CheckOptions: [ \
15 // RUN:   {key: modernize-loop-convert.MakeReverseRangeFunction, value: 'llvm::reverse'}]}"
16 
17 // Ensure the check doesn't transform reverse loops when not in c++20 mode or
18 // when UseCxx20ReverseRanges has been disabled
19 // RUN: clang-tidy %s -checks=-*,modernize-loop-convert -- -std=c++17 | count 0
20 
21 // RUN: clang-tidy %s -checks=-*,modernize-loop-convert -config="{CheckOptions: \
22 // RUN:     [{key: modernize-loop-convert.UseCxx20ReverseRanges, value: 'false'}] \
23 // RUN:     }" -- -std=c++20 | count 0
24 
25 // Ensure we get a warning if we supply the header argument without the
26 // function argument.
27 // RUN: clang-tidy %s -checks=-*,modernize-loop-convert -config="{CheckOptions: [ \
28 // RUN:   {key: modernize-loop-convert.MakeReverseRangeHeader, value: 'llvm/ADT/STLExtras.h'}]}" \
29 // RUN: -- -std=c++17 2>&1 \
30 // RUN:   | FileCheck %s -check-prefix=CHECK-HEADER-NO-FUNC \
31 // RUN:       -implicit-check-not="{{warning|error}}:"
32 
33 // CHECK-HEADER-NO-FUNC: warning: modernize-loop-convert: 'MakeReverseRangeHeader' is set but 'MakeReverseRangeFunction' is not, disabling reverse loop transformation
34 
35 // Make sure appropiate headers are included
36 // CHECK-FIXES-RANGES: #include <ranges>
37 // CHECK-FIXES-CUSTOM-NO-SYS: #include "llvm/ADT/STLExtras.h"
38 // CHECK-FIXES-CUSTOM-SYS: #include <llvm/ADT/STLExtras.h>
39 
40 // Make sure no header is included in this example
41 // CHECK-FIXES-CUSTOM-NO-HEADER-NOT: #include
42 
43 namespace ADL {
44 
45 template <typename T>
46 struct Reversable {
47   using iterator = T *;
48   using const_iterator = const T *;
49 
50   iterator begin();
51   iterator end();
52   iterator rbegin();
53   iterator rend();
54 
55   const_iterator begin() const;
56   const_iterator end() const;
57   const_iterator rbegin() const;
58   const_iterator rend() const;
59 
60   const_iterator cbegin() const;
61   const_iterator cend() const;
62   const_iterator crbegin() const;
63   const_iterator crend() const;
64 };
65 
66 template <typename C>
67 constexpr auto rbegin(C& c) -> decltype(c.rbegin()) { return c.rbegin(); }
68 template <typename C>
69 constexpr auto rend(C& c) -> decltype(c.rend()) { return c.rend(); }
70 template <typename C>
71 constexpr auto rbegin(const C& c) -> decltype(c.rbegin()) { return c.rbegin(); }
72 template <typename C>
73 constexpr auto rend(const C& c) -> decltype(c.rend()) { return c.rend(); }
74 
75 template <typename C>
76 constexpr auto crbegin(C& c) -> decltype(c.crbegin());
77 template <typename C>
78 constexpr auto crend(C& c) -> decltype(c.crend());
79 template <typename C>
80 constexpr auto crbegin(const C& c) -> decltype(c.crbegin());
81 template <typename C>
82 constexpr auto crend(const C& c) -> decltype(c.crend());
83 
84 } // namespace ADL
85 
86 using ADL::Reversable;
87 
88 template <typename T>
89 void observe(const T &);
90 template <typename T>
91 void mutate(T &);
92 
93 void constContainer(const Reversable<int> &Numbers) {
94   for (auto I = Numbers.rbegin(), E = Numbers.rend(); I != E; ++I) {
95     observe(*I);
96   }
97   // CHECK-MESSAGES: :[[@LINE-3]]:3: warning: use range-based for loop instead
98   // CHECK-FIXES-RANGES: for (int Number : std::ranges::reverse_view(Numbers)) {
99   // CHECK-FIXES-CUSTOM: for (int Number : llvm::reverse(Numbers)) {
100   //   CHECK-FIXES-NEXT:   observe(Number);
101   //   CHECK-FIXES-NEXT: }
102 
103   for (auto I = Numbers.crbegin(), E = Numbers.crend(); I != E; ++I) {
104     observe(*I);
105   }
106   // CHECK-MESSAGES: :[[@LINE-3]]:3: warning: use range-based for loop instead
107   // CHECK-FIXES-RANGES: for (int Number : std::ranges::reverse_view(Numbers)) {
108   // CHECK-FIXES-CUSTOM: for (int Number : llvm::reverse(Numbers)) {
109   //   CHECK-FIXES-NEXT:   observe(Number);
110   //   CHECK-FIXES-NEXT: }
111 
112   for (auto I = rbegin(Numbers), E = rend(Numbers); I != E; ++I) {
113     observe(*I);
114   }
115   // CHECK-MESSAGES: :[[@LINE-3]]:3: warning: use range-based for loop instead
116   // CHECK-FIXES-RANGES: for (int Number : std::ranges::reverse_view(Numbers)) {
117   // CHECK-FIXES-CUSTOM: for (int Number : llvm::reverse(Numbers)) {
118   //   CHECK-FIXES-NEXT:   observe(Number);
119   //   CHECK-FIXES-NEXT: }
120 
121   for (auto I = crbegin(Numbers), E = crend(Numbers); I != E; ++I) {
122     observe(*I);
123   }
124   // CHECK-MESSAGES: :[[@LINE-3]]:3: warning: use range-based for loop instead
125   // CHECK-FIXES-RANGES: for (int Number : std::ranges::reverse_view(Numbers)) {
126   // CHECK-FIXES-CUSTOM: for (int Number : llvm::reverse(Numbers)) {
127   //   CHECK-FIXES-NEXT:   observe(Number);
128   //   CHECK-FIXES-NEXT: }
129 
130   // Ensure these bad loops aren't transformed.
131   for (auto I = Numbers.rbegin(), E = Numbers.end(); I != E; ++I) {
132     observe(*I);
133   }
134   for (auto I = Numbers.begin(), E = Numbers.rend(); I != E; ++I) {
135     observe(*I);
136   }
137 }
138 
139 void nonConstContainer(Reversable<int> &Numbers) {
140   for (auto I = Numbers.rbegin(), E = Numbers.rend(); I != E; ++I) {
141     mutate(*I);
142   }
143   // CHECK-MESSAGES: :[[@LINE-3]]:3: warning: use range-based for loop instead
144   // CHECK-FIXES-RANGES: for (int & Number : std::ranges::reverse_view(Numbers)) {
145   // CHECK-FIXES-CUSTOM: for (int & Number : llvm::reverse(Numbers)) {
146   //   CHECK-FIXES-NEXT:   mutate(Number);
147   //   CHECK-FIXES-NEXT: }
148 
149   for (auto I = Numbers.crbegin(), E = Numbers.crend(); I != E; ++I) {
150     observe(*I);
151   }
152   // CHECK-MESSAGES: :[[@LINE-3]]:3: warning: use range-based for loop instead
153   // CHECK-FIXES-RANGES: for (int Number : std::ranges::reverse_view(Numbers)) {
154   // CHECK-FIXES-CUSTOM: for (int Number : llvm::reverse(Numbers)) {
155   //   CHECK-FIXES-NEXT:   observe(Number);
156   //   CHECK-FIXES-NEXT: }
157 
158   for (auto I = rbegin(Numbers), E = rend(Numbers); I != E; ++I) {
159     mutate(*I);
160   }
161   // CHECK-MESSAGES: :[[@LINE-3]]:3: warning: use range-based for loop instead
162   // CHECK-FIXES-RANGES: for (int & Number : std::ranges::reverse_view(Numbers)) {
163   // CHECK-FIXES-CUSTOM: for (int & Number : llvm::reverse(Numbers)) {
164   //   CHECK-FIXES-NEXT:   mutate(Number);
165   //   CHECK-FIXES-NEXT: }
166 }
167