Add a warning for StateSelect.always/never

If a non-state variable has StateSelect.always or a state variable has
StateSelect.never, we now give a warning during the SimCode phase.

This resolves ticket:3689.

Belonging to [master]:
  - OpenModelica/OMCompiler#2191
  - OpenModelica/OpenModelica-testsuite#867

Compiler/FrontEnd/ComponentReference.mo

@@ -1271,6 +1271,16 @@ algorithm
   end match;
 end isPreCref;
 
+public function isPreviousCref
+  input DAE.ComponentRef cr;
+  output Boolean b;
+algorithm
+  b := match(cr)
+    case(DAE.CREF_QUAL(ident=DAE.previousNamePrefix)) then true;
+    else false;
+  end match;
+end isPreviousCref;
+
 public function isStartCref
   input DAE.ComponentRef cr;
   output Boolean b;

Compiler/SimCode/SimCodeUtil.mo

@@ -8292,19 +8292,19 @@ algorithm
     SimCode.SparsityPattern sparsityT;
   case(SOME(dmd)) algorithm
     print("\ndaeMode: \n" + UNDERLINE + "\n");
-	  str := "residual Equations:\n"+UNDERLINE+"\n";
-	  print(str);
-	  dumpSimEqSystemLst(List.flatten(dmd.daeEquations),"\n");
-	  dumpVarLst(dmd.residualVars,"residualVars("+intString(listLength(dmd.residualVars))+")");
-	  dumpVarLst(dmd.algebraicVars,"algebraicDAEVars("+intString(listLength(dmd.algebraicVars))+")");
-	  dumpVarLst(dmd.auxiliaryVars,"auxVars("+intString(listLength(dmd.auxiliaryVars))+")");
-	  if isSome(dmd.sparsityPattern) then
-	    str := "Sparsity Pattern:\n"+UNDERLINE+"\n";
-	    print(str);
-	    SimCode.JAC_MATRIX(sparsityT=sparsityT) := Util.getOption(dmd.sparsityPattern);
-	    dumpSparsePatternInt(sparsityT);
-	  end if;
-	then ();
+    str := "residual Equations:\n"+UNDERLINE+"\n";
+    print(str);
+    dumpSimEqSystemLst(List.flatten(dmd.daeEquations),"\n");
+    dumpVarLst(dmd.residualVars,"residualVars("+intString(listLength(dmd.residualVars))+")");
+    dumpVarLst(dmd.algebraicVars,"algebraicDAEVars("+intString(listLength(dmd.algebraicVars))+")");
+    dumpVarLst(dmd.auxiliaryVars,"auxVars("+intString(listLength(dmd.auxiliaryVars))+")");
+    if isSome(dmd.sparsityPattern) then
+      str := "Sparsity Pattern:\n"+UNDERLINE+"\n";
+      print(str);
+      SimCode.JAC_MATRIX(sparsityT=sparsityT) := Util.getOption(dmd.sparsityPattern);
+      dumpSparsePatternInt(sparsityT);
+    end if;
+  then ();
   case(NONE()) then ();
   end match;
 end dumpSimCodeDAEmodeDataString;
@@ -8941,6 +8941,13 @@ algorithm
       varType = tp,
       source = source)), _, vars)
       equation
+        _ = match BackendVariable.varStateSelect(dlowVar)
+          case DAE.NEVER()
+            algorithm
+              Error.addSourceMessage(Error.STATE_STATESELECT_NEVER, {ComponentReference.printComponentRefStr(cr)}, source.info);
+            then ();
+          else ();
+        end match;
         commentStr = unparseCommentOptionNoAnnotationNoQuote(comment);
         (unit, displayUnit) = extractVarUnit(dae_var_attr);
         isProtected = getProtected(dae_var_attr);
@@ -8971,6 +8978,14 @@ algorithm
       varType = tp,
       source = source)), _, vars)
       equation
+        _ = match BackendVariable.varStateSelect(dlowVar)
+          case DAE.ALWAYS()
+            guard valueEq(kind, BackendDAE.VARIABLE()) and not ComponentReference.isPreviousCref(cr) /* TODO: Why are clocked variables continuous and not discrete? */
+            algorithm
+              Error.addSourceMessage(Error.NON_STATE_STATESELECT_ALWAYS, {ComponentReference.printComponentRefStr(cr)}, source.info);
+            then ();
+          else ();
+        end match;
         commentStr = unparseCommentOptionNoAnnotationNoQuote(comment);
         (unit, displayUnit) = extractVarUnit(dae_var_attr);
         isProtected = getProtected(dae_var_attr);

Compiler/Util/Error.mo

@@ -935,9 +935,9 @@ public constant Message EQN_NO_SPACE_TO_SOLVE = MESSAGE(581, SYMBOLIC(), WARNING
   Util.gettext("Equation %s (size: %s) %s is not big enough to solve for enough variables.\n  Remaining unsolved variables are: %s\n  Already solved: %s\n  Equations used to solve those variables:%s"));
 public constant Message VAR_NO_REMAINING_EQN = MESSAGE(582, SYMBOLIC(), WARNING(),
   Util.gettext("Variable %s does not have any remaining equation to be solved in.\n  The original equations were:%s"));
-public constant Message MOVING_PARAMETER_BINDING_TO_INITIAL_EQ_SECTION = MESSAGE(582, TRANSLATION(), NOTIFICATION(),
+public constant Message MOVING_PARAMETER_BINDING_TO_INITIAL_EQ_SECTION = MESSAGE(583, TRANSLATION(), NOTIFICATION(),
   Util.gettext("Moving binding to initial equation section and setting fixed attribute of %s to false."));
-public constant Message MIXED_DETERMINED = MESSAGE(583, SYMBOLIC(), ERROR(),
+public constant Message MIXED_DETERMINED = MESSAGE(584, SYMBOLIC(), ERROR(),
   Util.gettext("The given system is mixed-determined.   [index > %s]\nPlease checkout the option \"--maxMixedDeterminedIndex\"."));
 public constant Message STACK_OVERFLOW_DETAILED = MESSAGE(584, SCRIPTING(), ERROR(),
   Util.gettext("Stack overflow occurred while evaluating %s:\n%s"));
@@ -953,6 +953,10 @@ public constant Message NF_CAT_FIRST_ARG_EVAL = MESSAGE(589, TRANSLATION(), ERRO
   Util.gettext("The first argument of cat must be possible to evaluate during compile-time. Expression %s has variability %s."));
 public constant Message COMMA_OPERATOR_DIFFERENT_SIZES = MESSAGE(590, TRANSLATION(), ERROR(),
   Util.gettext("Arguments of concatenation comma operator have different sizes for the first dimension: %s has dimension %s and %s has dimension %s."));
+public constant Message NON_STATE_STATESELECT_ALWAYS = MESSAGE(591, SYMBOLIC(), WARNING(),
+  Util.gettext("Variable %s has attribute stateSelect=StateSelect.always, but was selected as a continuous variable."));
+public constant Message STATE_STATESELECT_NEVER = MESSAGE(592, SYMBOLIC(), WARNING(),
+  Util.gettext("Variable %s has attribute stateSelect=StateSelect.never, but was selected as a state"));
 
 public constant Message MATCH_SHADOWING = MESSAGE(5001, TRANSLATION(), ERROR(),
   Util.gettext("Local variable '%s' shadows another variable."));