[clang-tidy] Make MatchesAnyListedNameMatcher cope with unnamed Decl

[mikecrowe]

Summary

If MatchesAnyListedNameMatcher::NameMatcher::match() is called in
MatchMode::MatchUnqualified mode with a NamedDecl that has no name then
calling NamedDecl::getName() will assert with:
`Name.isIdentifier() && "Name is not a simple identifier"'

It seems unfair to force all matchers using
matchers::matchesAnyListedName to defend against this, particularly
since test cases are unlikely to provoke the problem. Let's just check
whether the identifier has a name before attempting to use it instead.

Add test case that reproduces the problem to the
use-std-print-custom.cpp lit check.

[PiotrZSL]

Remove example from commit message, it's already included in patch.
Simply commit message should be properly formatted without unnecessary information.

clang-tools-extra/clang-tidy/utils/Matchers.h

115–117

Not needed.

[mikecrowe]

Remove unnecessary init-statement and test case in commit message

[mikecrowe]

Thanks for the review.

[PiotrZSL]

LGTM

clang-tools-extra/clang-tidy/utils/Matchers.h

public:
 
     bool match(const NamedDecl &ND) const {
       switch (Mode) {
       case MatchMode::MatchQualified:
         return Regex.match(ND.getQualifiedNameAsString());
       case MatchMode::MatchFullyQualified:
         return Regex.match("::" + ND.getQualifiedNameAsString());
       default:
-        return Regex.match(ND.getName());
+        if (const IdentifierInfo *II = ND.getIdentifier())
+          return Regex.match(II->getName());
+        return false;
       }
     }
 
   private:
     MatchMode determineMatchMode(llvm::StringRef Regex) {
       if (Regex.startswith(":") || Regex.startswith("^:")) {
         return MatchMode::MatchFullyQualified;
       }

clang-tools-extra/test/clang-tidy/checkers/modernize/use-std-print-custom.cpp

 // RUN: %check_clang_tidy -std=c++23 %s modernize-use-std-print %t -- \
 // RUN:   -config="{CheckOptions: \
 // RUN:             [ \
 // RUN:              { \
 // RUN:               key: modernize-use-std-print.PrintfLikeFunctions, \
-// RUN:               value: '::myprintf; mynamespace::myprintf2' \
+// RUN:               value: 'unqualified_printf;::myprintf; mynamespace::myprintf2' \
 // RUN:              }, \
 // RUN:              { \
 // RUN:               key: modernize-use-std-print.FprintfLikeFunctions, \
 // RUN:               value: '::myfprintf; mynamespace::myfprintf2' \
 // RUN:              } \
 // RUN:             ] \
 // RUN:            }" \
 // RUN:   -- -isystem %clang_tidy_headers
 
 #include <cstdio>
-#include <string.h>
+#include <string>
 
 int myprintf(const char *, ...);
 int myfprintf(FILE *fp, const char *, ...);
 
 namespace mynamespace {
 int myprintf2(const char *, ...);
 int myfprintf2(FILE *fp, const char *, ...);
 }
void fprintf_newline(FILE *fp)
   fprintf(stderr, "Hello %s %d\n", "world", 42);
 }
 
 int fprintf_uses_return_value(int i) {
   return myfprintf(stderr, "return value %d\n", i);
   // CHECK-MESSAGES-NOT: [[@LINE-1]]:10: warning: use 'std::println' instead of 'myprintf' [modernize-use-std-print]
   // CHECK-FIXES-NOT: std::println(stderr, "return value {}", i);
 }
+
+// Ensure that MatchesAnyListedNameMatcher::NameMatcher::match() can cope with a
+// NamedDecl that has no name when we're trying to match unqualified_printf.
+void no_name(const std::string &in)
+{
+  "A" + in;
+}