[clang-tidy] Fix false negative modernize-use-ranges when using getter function
#127377
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@llvm/pr-subscribers-clang-tidy @llvm/pr-subscribers-clang-tools-extra Author: None (Andrewyuan34) ChangesThis PR fixes issue #124906, where Changes:
Linked Issue:Fixes #124906 . Testing:
Note: Full diff: https://github.com/llvm/llvm-project/pull/127377.diff 3 Files Affected:
diff --git a/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp b/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp
index aba4d17ccd035..f5fd0a47fb136 100644
--- a/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp
+++ b/clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp
@@ -51,7 +51,13 @@ static std::string getFullPrefix(ArrayRef<UseRangesCheck::Indexes> Signature) {
namespace {
AST_MATCHER(Expr, hasSideEffects) {
- return Node.HasSideEffects(Finder->getASTContext());
+ bool CheckArg = true;
+ if (const CXXMemberCallExpr *Call = dyn_cast<CXXMemberCallExpr>(&Node)) {
+ if (Call->isLValue() && Call->getMethodDecl()->isConst()) {
+ CheckArg = false;
+ }
+ }
+ return Node.HasSideEffects(Finder->getASTContext(), CheckArg);
}
} // namespace
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 6b8fe22242417..f97c46d3b5dff 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -110,6 +110,11 @@ Changes in existing checks
<clang-tidy/checks/misc/redundant-expression>` check by providing additional
examples and fixing some macro related false positives.
+- Improved :doc:`modernize-use-ranges
+ <clang-tidy/checks/modernize/use-ranges>` check by correctly recognizes
+ const member functions returning lvalues as side-effect-free, preventing
+ missed transformations.
+
Removed checks
^^^^^^^^^^^^^^
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-ranges.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-ranges.cpp
index b022efebfdf4d..63a6946728f6f 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-ranges.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-ranges.cpp
@@ -7,7 +7,15 @@
#include "fake_std.h"
-void Positives() {
+struct S {
+ std::vector<int> v;
+
+ const std::vector<int>& get() const { return v; }
+ std::vector<int>& getMutable() { return v; }
+ std::vector<int> getVal() const { return v; }
+};
+
+void Positives(S& s) {
std::vector<int> I, J;
std::find(I.begin(), I.end(), 0);
// CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use a ranges version of this algorithm
@@ -72,9 +80,19 @@ void Positives() {
my_std::find(I.begin(), I.end(), 6);
// CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use a ranges version of this algorithm
// CHECK-FIXES: std::ranges::find(I, 6);
+
+ std::find(s.get().begin(), s.get().end(), 0);
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use a ranges version of this algorithm
+ // CHECK-FIXES: std::ranges::find(s.get(), 0);
+
+ // Return non-const function, should not generate message
+ std::find(s.getMutable().begin(), s.getMutable().end(), 0);
+
+ // Return value, should not generate message
+ std::find(s.getVal().begin(), s.getVal().end(), 0);
}
-void Reverse(){
+void Reverse(S& s){
std::vector<int> I, J;
std::find(I.rbegin(), I.rend(), 0);
// CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use a ranges version of this algorithm
@@ -87,6 +105,16 @@ void Reverse(){
std::equal(I.begin(), I.end(), std::crbegin(J), std::crend(J));
// CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use a ranges version of this algorithm
// CHECK-FIXES: std::ranges::equal(I, std::ranges::reverse_view(J));
+
+ std::find(s.get().rbegin(), s.get().rend(), 0);
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use a ranges version of this algorithm
+ // CHECK-FIXES: std::ranges::find(std::ranges::reverse_view(s.get()), 0);
+
+ // Return non-const function, should not generate message
+ std::find(s.getMutable().rbegin(), s.getMutable().rend(), 0);
+
+ // Return value, should not generate message
+ std::find(s.getVal().rbegin(), s.getVal().rend(), 0);
}
void Negatives() {
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Ping |
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ping |
Thank you for your reply! Regarding freestanding functions, I have been struggling to come up with a suitable example that reproduces a similar issue. Could you kindly provide an example of a freestanding function where such an issue might occur? As for "all tests should should be convertible to ranges" |
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| bool CheckArg = true; | ||
| if (const CXXMemberCallExpr *Call = dyn_cast<CXXMemberCallExpr>(&Node)) { | ||
| if (Call->isLValue() && Call->getMethodDecl()->isConst()) { | ||
| CheckArg = false; | ||
| } | ||
| } |
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According to comment in HasSideEffects.
IncludePossibleEffects is false, this call treats certain expressions with potential side effects (such as function call-like expressions, instantiation-dependent expressions, or invocations from a macro) as not having side effects.
I think there are no relationship between Call->isLValue() && Call->getMethodDecl()->isConst() and IncludePossibleEffects.
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Maybe it is more straightforward to detect function which return ref of member variable like |
This PR fixes issue #124906, where
modernize-use-rangesfailed to detect cases where aconstmember function returning an lvalue was incorrectly assumed to have side effects, preventing the transformation.Changes:
Modified
clang-tools-extra/clang-tidy/utils/UseRangesCheck.cpp:hasSideEffectsAST matcher to correctly treatconstmember functions returning lvalues as side-effect-free.Added unit tests:
constgetters returning lvalues (should trigger transformation).Linked Issue:
Fixes #124906 .
Testing:
Note:
true), which leads to the incorrect assumption that the member function has side effects.falseexplicitly does not trigger this issue.constmember functions returning lvalues are correctly recognized as side-effect-free, preventing incorrect behavior.