Constant function parameters are not constant expressions.

src/OpenGL/compiler/ParseHelper.cpp

@@ -900,16 +900,16 @@ bool TParseContext::nonInitErrorCheck(int line, TString& identifier, TPublicType
 
 bool TParseContext::paramErrorCheck(int line, TQualifier qualifier, TQualifier paramQualifier, TType* type)
 {
-    if (qualifier != EvqConstExpr && qualifier != EvqTemporary) {
+    if (qualifier != EvqConstReadOnly && qualifier != EvqTemporary) {
         error(line, "qualifier not allowed on function parameter", getQualifierString(qualifier));
         return true;
     }
-    if (qualifier == EvqConstExpr && paramQualifier != EvqIn) {
+    if (qualifier == EvqConstReadOnly && paramQualifier != EvqIn) {
         error(line, "qualifier not allowed with ", getQualifierString(qualifier), getQualifierString(paramQualifier));
         return true;
     }
 
-    if (qualifier == EvqConstExpr)
+    if (qualifier == EvqConstReadOnly)
         type->setQualifier(EvqConstReadOnly);
     else
         type->setQualifier(paramQualifier);

src/OpenGL/compiler/glslang.y

@@ -1499,7 +1499,7 @@ fully_specified_type
 
 parameter_type_qualifier
     : CONST_QUAL {
-        $$ = EvqConstExpr;
+        $$ = EvqConstReadOnly;
     }
     ;
 

src/OpenGL/compiler/glslang_tab.cpp

@@ -3689,7 +3689,7 @@ yyreduce:
   case 105:
 
     {
-        (yyval.interm.qualifier) = EvqConstExpr;
+        (yyval.interm.qualifier) = EvqConstReadOnly;
     }
     break;