CheckLeakAutoVar: --check-library accepts <use> functions

Passing an allocated pointer to a function configured as <use> still gave
  --check-library: Function f() should have <use>/<leak-ignore> configuration
The reference says <use> is there to silence exactly that message, so do
not report functions that have it.

Author: pduchi

lib/checkleakautovar.cpp

@@ -138,7 +138,8 @@ void CheckLeakAutoVarImpl::deallocReturnError(const Token *tok, const Token *dea
 void CheckLeakAutoVarImpl::configurationInfo(const Token* tok, const std::pair<const Token*, VarInfo::Usage>& functionUsage)
 {
     if (mSettings.checkLibrary && functionUsage.second == VarInfo::USED &&
-        (!functionUsage.first || !functionUsage.first->function() || !functionUsage.first->function()->hasBody())) {
+        (!functionUsage.first || !functionUsage.first->function() || !functionUsage.first->function()->hasBody()) &&
+        !(functionUsage.first && mSettings.library.isUse(mSettings.library.getFunctionName(functionUsage.first)))) {
         std::string funcStr = functionUsage.first ? mSettings.library.getFunctionName(functionUsage.first) : "f";
         if (funcStr.empty())
             funcStr = "unknown::" + functionUsage.first->str();

test/testleakautovar.cpp

@@ -202,6 +202,7 @@ class TestLeakAutoVar : public TestFixture {
         TEST_CASE(configuration4);
         TEST_CASE(configuration5);
         TEST_CASE(configuration6);
+        TEST_CASE(configurationUse);
 
         TEST_CASE(ptrptr);
 
@@ -3102,6 +3103,29 @@ class TestLeakAutoVar : public TestFixture {
         ASSERT_EQUALS("[test.cpp:5:5]: (error) Resource leak: file [resourceLeak]\n", errout_str());
     }
 
+    void configurationUse() {
+        // A function configured with <use> takes care of the memory, so it needs
+        // no further configuration.
+        constexpr char xmldata[] = "<?xml version=\"1.0\"?>\n"
+                                   "<def format=\"2\">\n"
+                                   "  <memory>\n"
+                                   "    <alloc>myalloc</alloc>\n"
+                                   "    <use>set_data</use>\n"
+                                   "    <dealloc>myfree</dealloc>\n"
+                                   "  </memory>\n"
+                                   "  <function name=\"set_data\">\n"
+                                   "    <noreturn>false</noreturn>\n"
+                                   "    <arg nr=\"1\"/>\n"
+                                   "  </function>\n"
+                                   "</def>\n";
+        const Settings settingsUse = settingsBuilder().libraryxml(xmldata).checkLibrary().build();
+        check("void f() {\n"
+              "    char *p = myalloc(10);\n"
+              "    set_data(p);\n"
+              "}\n", settingsUse);
+        ASSERT_EQUALS("", errout_str());
+    }
+
     void configuration6() {
         check("void f() {}\n" // #11198
               "void g() {\n"