[clang-tidy] add regression test to performance-unnecessary-value-param

[chh]

Summary

This test shows the problem in https://bugs.llvm.org/show_bug.cgi?id=33734

[chh]

These tests should be added after https://bugs.llvm.org/show_bug.cgi?id=33734 is fixed.

[alexfh]

test/clang-tidy/performance-unnecessary-value-param.cpp

1

I'd leave this test alone and add a separate one to test the fix in the header.

2

No need to copy this file, the test doesn't change it.

[alexfh]

LG. Thanks!

test/clang-tidy/Inputs/performance-unnecessary-value-param/header-fixed.h

+// struct ABC is expensive to copy and should be
+// passed as a const referece.
+struct ABC {
+  ABC(const ABC&);
+  int get(int) const;
+};
+
+
+int f1(int n,              const ABC& v1,   const ABC& v2); // line 9
+
+int f1(int n, ABC v1); // line 11
+
+
+
+int f2(        int n,       const ABC& v2); // line 15

test/clang-tidy/Inputs/performance-unnecessary-value-param/header.h

+// struct ABC is expensive to copy and should be
+// passed as a const referece.
+struct ABC {
+  ABC(const ABC&);
+  int get(int) const;
+};
+
+
+int f1(int n,              ABC v1,   ABC v2); // line 9
+
+int f1(int n, ABC v1); // line 11
+
+
+
+int f2(        int n,       ABC v2); // line 15

test/clang-tidy/performance-unnecessary-value-param.cpp

-// RUN: %check_clang_tidy %s performance-unnecessary-value-param %t
+// RUN: cp %S/Inputs/performance-unnecessary-value-param/header.h %T/header.h
+// RUN: cp %S/Inputs/performance-unnecessary-value-param/header-fixed.h %T/header-fixed.h
+// RUN: %check_clang_tidy %s performance-unnecessary-value-param %t -- -- -std=c++11 -I %T
+// RUN: diff %T/header.h %T/header-fixed.h
 
+#include "header.h"
 // CHECK-FIXES: #include <utility>
 
+int f1(int n, ABC v1, ABC v2) {
+  // CHECK-MESSAGES: [[@LINE-1]]:19: warning: the parameter 'v1' is copied for each invocation but only used as a const reference; consider making it a const reference [performance-unnecessary-value-param]
+  // CHECK-MESSAGES: [[@LINE-2]]:27: warning: the parameter 'v2' is copied for each invocation but only used as a const reference; consider making it a const reference [performance-unnecessary-value-param]
+  // CHECK-FIXES: int f1(int n, const ABC& v1, const ABC& v2) {
+  return v1.get(n) + v2.get(n);
+}
+int f2(int n, ABC v2) {
+  // CHECK-MESSAGES: [[@LINE-1]]:19: warning: the parameter 'v2' is copied for each invocation but only used as a const reference; consider making it a const reference [performance-unnecessary-value-param]
+  // CHECK-FIXES: int f2(int n, const ABC& v2) {
+}
+
 struct ExpensiveToCopyType {
   const ExpensiveToCopyType & constReference() const {
     return *this;
   }
   void nonConstMethod();
   virtual ~ExpensiveToCopyType();
 };