diff --git a/lib/tokenize.cpp b/lib/tokenize.cpp
index dd1343c16..151528942 100644
--- a/lib/tokenize.cpp
+++ b/lib/tokenize.cpp
@@ -3586,8 +3586,10 @@ bool Tokenizer::simplifyTokenList1(const char FileName[])
     // then unsimplified function calls etc remain. These have the
     // "wrong" syntax. So this function will just fix so that the
     // syntax is corrected.
-    if (!isC())
+    if (!isC()) {
+        validate(); // #6847 - invalid code
         TemplateSimplifier::cleanupAfterSimplify(list.front());
+    }
 
     // Simplify pointer to standard types (C only)
     simplifyPointerToStandardType();
@@ -3642,13 +3644,8 @@ bool Tokenizer::simplifyTokenList1(const char FileName[])
 
     elseif();
 
-    // Simplify nameless rValue references - named ones are simplified later
-    for (Token* tok = list.front(); tok; tok = tok->next()) {
-        if (Token::Match(tok, "&& [,)]")) {
-            tok->str("&");
-            tok->insertToken("&");
-        }
-    }
+    SimplifyNamelessRValueReferences();
+
 
     validate();
     return true;
@@ -10496,3 +10493,14 @@ void Tokenizer::setPodTypes()
         }
     }
 }
+
+void Tokenizer::SimplifyNamelessRValueReferences()
+{
+    // Simplify nameless rValue references - named ones are simplified later
+    for (Token* tok = list.front(); tok; tok = tok->next()) {
+        if (Token::Match(tok, "&& [,)]")) {
+            tok->str("&");
+            tok->insertToken("&");
+        }
+    }
+}
diff --git a/lib/tokenize.h b/lib/tokenize.h
index 4614a9cbc..c793a73b1 100644
--- a/lib/tokenize.h
+++ b/lib/tokenize.h
@@ -118,6 +118,8 @@ public:
     */
     bool simplifyTokenList1(const char FileName[]);
 
+    void SimplifyNamelessRValueReferences();
+
     /**
     * Most aggressive simplification of tokenlist
     *
diff --git a/test/testgarbage.cpp b/test/testgarbage.cpp
index 7773852c3..4df2edfbb 100644
--- a/test/testgarbage.cpp
+++ b/test/testgarbage.cpp
@@ -143,6 +143,7 @@ private:
         TEST_CASE(garbageCode101); // #6835
         TEST_CASE(garbageCode102); // #6846
         TEST_CASE(garbageCode103); // #6824
+        TEST_CASE(garbageCode104); // #6847
 
         TEST_CASE(garbageValueFlow);
         TEST_CASE(garbageSymbolDatabase);
@@ -809,6 +810,10 @@ private:
         ASSERT_THROW(checkCode("a f(r) int * r; { { int s[2]; [f(s); if () ]  } }"), InternalError);
     }
 
+    void garbageCode104() { // #6847
+        ASSERT_THROW(checkCode("template < Types > struct S {> ( S < ) S >} { ( ) { } } ( ) { return S < void > ( ) } { ( )> >} { ( ) { } } ( ) { ( ) }"), InternalError);
+    }
+
     void garbageValueFlow() {
         // #6089
         const char* code = "{} int foo(struct, x1, struct x2, x3, int, x5, x6, x7)\n"