Detect tuples used as expressions

This fixes ticket:4007. Tuples may only be used on the left side of an
assignment in Modelica. In MetaModelica, we allow tuples anywhere.

Compiler/FrontEnd/InstSection.mo

@@ -334,8 +334,7 @@ algorithm
         // Check that the equation is valid if the lhs is a tuple.
         checkTupleCallEquationMessage(lhs_aexp, rhs_aexp, info);
 
-        (outCache, lhs_exp, lhs_prop) :=
-          Static.elabExp(inCache, inEnv, lhs_aexp, inImpl, NONE(), true, inPrefix, info);
+        (outCache, lhs_exp, lhs_prop) := Static.elabExpLHS(inCache, inEnv, lhs_aexp, inImpl, NONE(), true, inPrefix, info);
         (outCache, rhs_exp, rhs_prop) :=
           Static.elabExp(inCache, inEnv, rhs_aexp, inImpl, NONE(), true, inPrefix, info);
 
@@ -1112,7 +1111,7 @@ algorithm
       true = boolOr(b3,b4);
       true = Expression.containFunctioncall(elabedE2);
       (e1,prop) = expandTupleEquationWithWild(e1,prop2,prop);
-      (cache,elabedE1_2,prop1,_) = Static.elabExp(cache,env, e1, impl,NONE(),false,pre,info);
+      (cache,elabedE1_2,prop1,_) = Static.elabExpLHS(cache,env, e1, impl,NONE(),false,pre,info);
       (cache, elabedE1_2, prop1) = Ceval.cevalIfConstant(cache, env, elabedE1_2, prop1, impl, info);
       (cache,elabedE2_2,prop2,_) = Static.elabExp(cache,env, e2, impl,NONE(),false,pre,info);
       (cache, elabedE2_2, prop2) = Ceval.cevalIfConstant(cache, env, elabedE2_2, prop2, impl, info);
@@ -5099,7 +5098,7 @@ algorithm
       equation
         Absyn.CALL() = inRhs;
         true = List.all(expl, Absyn.isCref);
-        (cache,e_1,prop1,_) = Static.elabExp(cache,inEnv,e1,inImpl,NONE(),false,inPre,info);
+        (cache,e_1,prop1,_) = Static.elabExpLHS(cache,inEnv,e1,inImpl,NONE(),false,inPre,info);
         lt = Types.getPropType(prop1);
         rt = Types.getPropType(prop2);
         false = Types.subtype(lt, rt);

Compiler/FrontEnd/Static.mo

@@ -288,18 +288,7 @@ function: elabExp
   DAE.Properties type, and include the type and the variability of the
   expression.  This function performs analysis, and returns an
   DAE.Exp and the properties."
-  input FCore.Cache inCache;
-  input FCore.Graph inEnv;
-  input Absyn.Exp inExp;
-  input Boolean inImplicit;
-  input Option<GlobalScript.SymbolTable> inST;
-  input Boolean inDoVect;
-  input Prefix.Prefix inPrefix;
-  input SourceInfo inInfo;
-  output FCore.Cache outCache = inCache;
-  output DAE.Exp outExp;
-  output DAE.Properties outProperties;
-  output Option<GlobalScript.SymbolTable> outST = inST;
+  extends PartialElabExpFunc;
 protected
   Absyn.Exp e;
   Integer num_errmsgs;
@@ -354,7 +343,7 @@ algorithm
   end try;
 end elabExp;
 
-protected partial function PartialElabExpFunc
+public partial function PartialElabExpFunc
   input FCore.Cache inCache;
   input FCore.Graph inEnv;
   input Absyn.Exp inExp;
@@ -642,6 +631,13 @@ end elabExp_PartEvalFunction;
 
 protected function elabExp_Tuple
   extends PartialElabExpFunc;
+algorithm
+  (outCache, outExp, outProperties, outST) := elabExp_Tuple_LHS_RHS(inCache, inEnv, inExp, inImplicit, inST, inDoVect, inPrefix, inInfo);
+end elabExp_Tuple;
+
+protected function elabExp_Tuple_LHS_RHS
+  extends PartialElabExpFunc;
+  input Boolean isLhs=false;
 protected
   list<Absyn.Exp> el;
   list<DAE.Exp> expl;
@@ -651,10 +647,25 @@ protected
 algorithm
   Absyn.TUPLE(expressions = el) := inExp;
   (outCache, expl, props) := elabTuple(outCache, inEnv, el, inImplicit,
-    inDoVect, inPrefix, inInfo);
+    inDoVect, inPrefix, inInfo, isLhs);
   (types, consts) := splitProps(props);
   (outExp, outProperties) := fixTupleMetaModelica(expl, types, consts);
-end elabExp_Tuple;
+end elabExp_Tuple_LHS_RHS;
+
+public function elabExpLHS "Special check for tuples, which only occur on the LHS"
+  extends PartialElabExpFunc;
+algorithm
+  (outCache, outExp, outProperties, outST) := match inExp
+    case Absyn.TUPLE()
+      algorithm
+       (outCache, outExp, outProperties, outST) := elabExp_Tuple_LHS_RHS(inCache, inEnv, inExp, inImplicit, inST, inDoVect, inPrefix, inInfo, isLhs=true);
+      then (outCache, outExp, outProperties, outST);
+    else
+      algorithm
+       (outCache, outExp, outProperties, outST) := elabExp(inCache, inEnv, inExp, inImplicit, inST, inDoVect, inPrefix, inInfo);
+      then (outCache, outExp, outProperties, outST);
+  end match;
+end elabExpLHS;
 
 protected function elabExp_Range
   "Elaborates a range expression on the form start:stop or start:step:stop."
@@ -2287,7 +2298,7 @@ algorithm
     // The output from functions does just have one const flag. Fix this!!
     case (cache,env,Absyn.TUPLE(expressions = (es as (_ :: _))),impl,pre,_)
       equation
-        (cache,es_1,props) = elabTuple(cache,env,es,impl,false,pre,info);
+        (cache,es_1,props) = elabTuple(cache,env,es,impl,false,pre,info,false);
         (types,consts) = splitProps(props);
       then
         (cache,DAE.TUPLE(es_1),DAE.PROP_TUPLE(DAE.T_TUPLE(types,NONE(),DAE.emptyTypeSource),DAE.TUPLE_CONST(consts)));
@@ -2534,13 +2545,20 @@ protected function elabTuple
   input Boolean inDoVect;
   input Prefix.Prefix inPrefix;
   input SourceInfo inInfo;
+  input Boolean isLhs;
   output FCore.Cache outCache = inCache;
   output list<DAE.Exp> outExpl = {};
   output list<DAE.Properties> outProperties = {};
 protected
   DAE.Exp exp;
   DAE.Properties prop;
 algorithm
+
+  if if not isLhs then not Config.acceptMetaModelicaGrammar() else false then
+    Error.addSourceMessage(Error.RHS_TUPLE_EXPRESSION, {Dump.printExpStr(Absyn.TUPLE(inExpl))}, inInfo);
+    fail();
+  end if;
+
   for e in inExpl loop
     (outCache, exp, prop) :=
       elabExp(outCache, inEnv, e, inImplicit, NONE(), inDoVect, inPrefix, inInfo);

Compiler/Util/Error.mo

@@ -706,6 +706,8 @@ public constant Message NO_JACONIAN_TORNLINEAR_SYSTEM = MESSAGE(289, SYMBOLIC(),
   Util.gettext("A torn linear system has no symbolic jacobian and currently there are no means to solve that numerically. Please compile with the module \"calculateStrongComponentJacobians\" to provide symbolic jacobians for torn linear systems."));
 public constant Message EXT_FN_SINGLE_RETURN_ARRAY = MESSAGE(290, TRANSLATION(), WARNING(),
   Util.gettext("An external declaration with a single output without explicit mapping is defined as having the output as the lhs, but language %s does not support this for array variables. OpenModelica will put the output as an input (as is done when there is more than 1 output), but this is not according to the Modelica Specification. Use an explicit mapping instead of the implicit one to suppress this warning."));
+public constant Message RHS_TUPLE_EXPRESSION = MESSAGE(291, TRANSLATION(), ERROR(),
+  Util.gettext("Tuple expressions may only occur on the left side of an assignment or equation with a single function call on the right side. Got the following expression: %s."));
 
 public constant Message UNBOUND_PARAMETER_WITH_START_VALUE_WARNING = MESSAGE(499, TRANSLATION(), WARNING(),
   Util.gettext("Parameter %s has no value, and is fixed during initialization (fixed=true), using available start value (start=%s) as default value."));