diff --git a/lib/tokenize.cpp b/lib/tokenize.cpp
index 8ec538f45..a701f1150 100644
--- a/lib/tokenize.cpp
+++ b/lib/tokenize.cpp
@@ -4858,9 +4858,9 @@ bool Tokenizer::simplifyConstTernaryOp()
         const int offset = (tok->previous()->str() == ")") ? 2 : 1;
 
         bool inTemplateParameter = false;
-        if (!isC() && tok->strAt(-2*offset) == "<") {
-            if (!TemplateSimplifier::templateParameters(tok->tokAt(-2*offset)))
-                continue;
+        if (tok->strAt(-2*offset) == "<") {
+            if (isC() || !TemplateSimplifier::templateParameters(tok->tokAt(-2*offset)))
+                continue; // '<' is less than; the condition is not a constant
             inTemplateParameter = true;
         }
 
diff --git a/test/testbool.cpp b/test/testbool.cpp
index 0d09f6597..c854b6971 100644
--- a/test/testbool.cpp
+++ b/test/testbool.cpp
@@ -136,7 +136,17 @@ private:
               "}");
         ASSERT_EQUALS("", errout.str());
 
-        // ticket #6588
+        // ticket #6588 (c mode)
+        check("struct MpegEncContext { int *q_intra_matrix, *q_chroma_intra_matrix; };\n"
+              "void dnxhd_10bit_dct_quantize(MpegEncContext *ctx, int n, int qscale) {\n"
+              "  const int *qmat = n < 4;\n" /* KO */
+              "  const int *rmat = n < 4 ? " /* OK */
+              "                       ctx->q_intra_matrix :"
+              "                       ctx->q_chroma_intra_matrix;\n"
+              "}", /*experimental=*/false, "test.c");
+        ASSERT_EQUALS("[test.c:3]: (error) Boolean value assigned to pointer.\n", errout.str());
+
+        // ticket #6588 (c++ mode)
         check("struct MpegEncContext { int *q_intra_matrix, *q_chroma_intra_matrix; };\n"
               "void dnxhd_10bit_dct_quantize(MpegEncContext *ctx, int n, int qscale) {\n"
               "  const int *qmat = n < 4;\n" /* KO */
diff --git a/test/testother.cpp b/test/testother.cpp
index a8507cbc1..9d06dc254 100644
--- a/test/testother.cpp
+++ b/test/testother.cpp
@@ -555,7 +555,7 @@ private:
 
     }
 
-    void invalidFunctionUsage(const char code[]) {
+    void invalidFunctionUsage(const char code[], bool isCPP = true) {
         // Clear the error buffer..
         errout.str("");
 
@@ -573,7 +573,7 @@ private:
         // Tokenize..
         Tokenizer tokenizer(&settings, this);
         std::istringstream istr(code);
-        tokenizer.tokenize(istr, "test.cpp");
+        tokenizer.tokenize(istr, isCPP ? "test.cpp" : "test.c");
 
         // Check for redundant code..
         CheckOther checkOther(&tokenizer, &settings, this);
@@ -587,6 +587,14 @@ private:
         invalidFunctionUsage("int f() { memset(a,b,sizeof(a)!=0); }");
         ASSERT_EQUALS("[test.cpp:1]: (error) Invalid memset() argument nr 3. A non-boolean value is required.\n", errout.str());
 
+        // Ticket #6588 (c mode)
+        invalidFunctionUsage("void record(char* buf, int n) {\n"
+                             "  memset(buf, 0, n < 255);\n"           /* KO */
+                             "  memset(buf, 0, n < 255 ? n : 255);\n" /* OK */
+                             "}", /*isCPP=*/false);
+        ASSERT_EQUALS("[test.c:2]: (error) Invalid memset() argument nr 3. A non-boolean value is required.\n", errout.str());
+
+        // Ticket #6588 (c++ mode)
         invalidFunctionUsage("void record(char* buf, int n) {\n"
                              "  memset(buf, 0, n < 255);\n"           /* KO */
                              "  memset(buf, 0, n < 255 ? n : 255);\n" /* OK */