[clang-tools-extra] [clang-tidy] performance-unnecessary-copy-initialization: Consider static functions (PR #119974)

[Julian Schmidt via cfe-commits]

================
@@ -104,14 +104,16 @@ AST_MATCHER_FUNCTION_P(StatementMatcher,
                                 hasArgument(0, hasType(ReceiverType)))));
 }
 
+AST_MATCHER(CXXMethodDecl, isStatic) { return Node.isStatic(); }
+
 AST_MATCHER_FUNCTION(StatementMatcher, isConstRefReturningFunctionCall) {
   // Only allow initialization of a const reference from a free function if it
   // has no arguments. Otherwise it could return an alias to one of its
   // arguments and the arguments need to be checked for const use as well.
   return callExpr(callee(functionDecl(returns(hasCanonicalType(
                                           matchers::isReferenceToConst())))
                              .bind(FunctionDeclId)),
-                  argumentCountIs(0), unless(callee(cxxMethodDecl())))
+                  argumentCountIs(0), unless(callee(cxxMethodDecl(unless(isStatic())))))
----------------
5chmidti wrote:

Please change `of a free function` to `from a call to a free function or static member function` in the comment above.

You can also move the check for the method and static inward:
```
callExpr(callee(functionDecl(returns(hasCanonicalType(matchers::isReferenceToConst())), 
                             unless(cxxMethodDecl(unless(isStatic()))))
                             .bind(FunctionDeclId)),
                  argumentCountIs(0))
```

Unrelated to this PR, but if you reorder anyway: please move the `argumentCountIs` to the front inside `callExpr`.

https://github.com/llvm/llvm-project/pull/119974