Fixed #4955 (false positive: Variable 'i' is assigned a value that is never used (only used in template instantiation))

Author: danmar

lib/checkunusedvar.cpp

@@ -769,6 +769,10 @@ void CheckUnusedVar::checkFunctionVariableUsage_iterateScopes(const Scope* const
             variables.clear();
             break;
         }
+        if (tok->isName() && tok->str().back() == '>') {
+            variables.clear();
+            break;
+        }
 
         // bailout when for_each is used
         if (Token::Match(tok, "%name% (") && Token::simpleMatch(tok->linkAt(1), ") {") && !Token::Match(tok, "if|for|while|switch")) {

test/testunusedvar.cpp

@@ -156,6 +156,7 @@ class TestUnusedVar : public TestFixture {
         TEST_CASE(localvarUnusedGoto);    // #4447, #4558 goto
         TEST_CASE(localvarRangeBasedFor); // #7075
         TEST_CASE(localvarAssignInWhile);
+        TEST_CASE(localvarTemplate); // #4955 - variable is used as template parameter
 
         TEST_CASE(localvarCppInitialization);
         TEST_CASE(localvarCpp11Initialization);
@@ -3875,6 +3876,15 @@ class TestUnusedVar : public TestFixture {
         ASSERT_EQUALS("", errout.str());
     }
 
+    void localvarTemplate() {
+        functionVariableUsage("template<int A> void f() {}\n"
+                              "void foo() {\n"
+                              "  const int x = 0;\n"
+                              "  f<x>();\n"
+                              "}");
+        ASSERT_EQUALS("", errout.str());
+    }
+
     void chainedAssignment() {
         // #5466
         functionVariableUsage("void NotUsed(double* pdD, int n) {\n"