Partial fix for #12923: syntaxError for valid template declaration (#6603)

This avoids saving names that appear after the assignment operator
within a template parameter declaration.

Note that is only fixes the initial example shown in the ticket
description; the other examples in the first comment seem trickier to
solve at the moment.

Author: ehlert-battelle

lib/token.cpp

@@ -897,7 +897,7 @@ const Token * Token::findClosingBracket() const
         }
         // save named template parameter
         else if (templateParameter && depth == 1 && Token::Match(closing, "[,=]") &&
-                 closing->previous()->isName() && !Token::Match(closing->previous(), "class|typename|."))
+                 closing->previous()->isName() && !Token::Match(closing->previous(), "class|typename|.") && !Token::Match(closing->tokAt(-2), "=|::"))
             templateParameters.insert(closing->strAt(-1));
     }
 

test/testtoken.cpp

@@ -109,6 +109,7 @@ class TestToken : public TestFixture {
         TEST_CASE(findClosingBracket);
         TEST_CASE(findClosingBracket2);
         TEST_CASE(findClosingBracket3);
+        TEST_CASE(findClosingBracket4);
 
         TEST_CASE(expressionString);
 
@@ -1190,6 +1191,16 @@ class TestToken : public TestFixture {
         ASSERT(t && Token::simpleMatch(t->findClosingBracket(), ">"));
     }
 
+    void findClosingBracket4() {
+        const SimpleTokenizer var(*this, // #12923
+                                  "template<template<class E> class T = std::vector, class U = std::vector<int>, class V = void>\n"
+                                  "class C;\n");
+        const Token *const t = Token::findsimplematch(var.tokens(), "<");
+        ASSERT(t);
+        const Token *const closing = t->findClosingBracket();
+        ASSERT(closing && closing == var.tokens()->tokAt(28));
+    }
+
     void expressionString() {
         const SimpleTokenizer var1(*this, "void f() { *((unsigned long long *)x) = 0; }");
         const Token *const tok1 = Token::findsimplematch(var1.tokens(), "*");