Fix bug #2139

- better handling of if equations counting 
  if false then eq; end if;
- add test for it:
  testsuite/flattening/libraries/msl32/testquasi.mo
  testsuite/flattening/libraries/msl32/testquasi.mos



git-svn-id: https://openmodelica.org/svn/OpenModelica/trunk@15843 f25d12d1-65f4-0310-ae8a-bbce733d8d8e

Compiler/FrontEnd/CheckModel.mo

@@ -243,6 +243,13 @@ algorithm
       then
         (varSize,eqnSize,eqns,hs);
 
+    // if equation with condition false and no else
+    case (DAE.IF_EQUATION(condition1 = {DAE.BCONST(false)}, equations3 = {})::rest,_,_,_,_)
+      equation
+        (varSize,eqnSize,eqns,hs) = countVarEqnSize(rest,ivarSize,ieqnSize,ieqnslst,ihs);
+      then
+        (varSize,eqnSize,eqns,hs);
+
     // if equation that cannot be translated to if expression but have initial() as condition
     case (DAE.IF_EQUATION(condition1 = {DAE.CALL(path=Absyn.IDENT("initial"))})::rest,_,_,_,_)
       equation
@@ -257,6 +264,14 @@ algorithm
         (varSize,eqnSize,eqns,hs) = countVarEqnSize(rest,ivarSize,ieqnSize+size,ieqnslst,ihs);
       then
         (varSize,eqnSize,eqns,hs);
+
+    // initial if equation with condition false and no else
+    case (DAE.INITIAL_IF_EQUATION(condition1 = {DAE.BCONST(false)}, equations3 = {})::rest,_,_,_,_)
+      equation
+        (varSize,eqnSize,eqns,hs) = countVarEqnSize(rest,ivarSize,ieqnSize,ieqnslst,ihs);
+      then
+        (varSize,eqnSize,eqns,hs);
+
     // initial if equation
     case (DAE.INITIAL_IF_EQUATION(condition1 = _)::rest,_,_,_,_)
       equation