Fix #15072: Type aliases not simplified in templates (#8904)

Author: ludviggunne

lib/tokenize.cpp

@@ -3201,8 +3201,15 @@ bool Tokenizer::simplifyUsing()
                 continue;
             }
 
-            // skip template definitions
             if (Token::Match(tok1, "template < !!>")) {
+                Token *paramsEnd = tok1->next()->findClosingBracket();
+                bool shadowed = !paramsEnd;
+                for (const Token *param = tok1->next(); !shadowed && param != paramsEnd; param = param->next())
+                    shadowed = param->str() == nameToken->str();
+                if (!shadowed) {
+                    tok1 = paramsEnd;
+                    continue;
+                }
                 Token *declEndToken = TemplateSimplifier::findTemplateDeclarationEnd(tok1);
                 if (declEndToken)
                     tok1 = declEndToken;

test/testsimplifyusing.cpp

@@ -79,6 +79,7 @@ class TestSimplifyUsing : public TestFixture {
         TEST_CASE(simplifyUsing39);
         TEST_CASE(simplifyUsing40);
         TEST_CASE(simplifyUsing41);
+        TEST_CASE(simplifyUsing42);
 
         TEST_CASE(simplifyUsing8970);
         TEST_CASE(simplifyUsing8971);
@@ -956,6 +957,40 @@ class TestSimplifyUsing : public TestFixture {
         ASSERT_EQUALS(expected, tok(code));
     }
 
+    void simplifyUsing42() {
+        {
+            const char code[] = "using A = bool;\n"
+                                "template<typename T> A func() {}\n";
+            const char expected[] = "template < typename T > bool func ( ) { }";
+            ASSERT_EQUALS(expected, tok(code));
+        }
+        {
+            const char code[] = "using A = bool;\n"
+                                "template<typename A> A func() {}\n";
+            const char expected[] = "template < typename A > A func ( ) { }";
+            ASSERT_EQUALS(expected, tok(code));
+        }
+        {
+            const char code[] = "using A = bool;\n"
+                                "template<typename T> class C { A x; }\n";
+            const char expected[] = "template < typename T > class C { bool x ; }";
+            ASSERT_EQUALS(expected, tok(code));
+        }
+        {
+            const char code[] = "using A = bool;\n"
+                                "template<typename A> class C { A x; }\n";
+            const char expected[] = "template < typename A > class C { A x ; }";
+            ASSERT_EQUALS(expected, tok(code));
+        }
+        {
+            const char code[] = "using A = bool;\n"
+                                "template<typename T> class C { using A = T; A x; }\n"
+                                "C<int> c;\n";
+            const char expected[] = "class C<int> ; C<int> c ; class C<int> { int x ; }";
+            ASSERT_EQUALS(expected, tok(code));
+        }
+    }
+
     void simplifyUsing8970() {
         const char code[] = "using V = std::vector<int>;\n"
                             "struct A {\n"