Improve handling of if/for containing connections (#11694)

- Mark if-conditions/for-ranges as structural if they are parameter
  expressions and the if/for contains connections.

Fixes #11606

OMCompiler/Compiler/NFFrontEnd/NFComponent.mo

@@ -357,6 +357,24 @@ public
     end if;
   end getImplicitBinding;
 
+  function getTypeAttributeBinding
+    input Component component;
+    input String attrName;
+    output Binding binding;
+  protected
+    InstNode start_node;
+    Component start_comp;
+  algorithm
+    try
+      start_node := Class.lookupElement(attrName, InstNode.getClass(classInstance(component)));
+      start_comp := InstNode.component(start_node);
+      true := Component.isTypeAttribute(start_comp);
+      binding := Component.getBinding(start_comp);
+    else
+      binding := NFBinding.EMPTY_BINDING;
+    end try;
+  end getTypeAttributeBinding;
+
   function setBinding
     input Binding binding;
     input output Component component;

OMCompiler/Compiler/NFFrontEnd/NFEquation.mo

@@ -45,6 +45,7 @@ protected
   import FlatModelicaUtil = NFFlatModelicaUtil;
   import IOStream;
   import Util;
+  import Call = NFCall;
 
 public
   uniontype Branch
@@ -1180,6 +1181,7 @@ public
   end replaceIteratorList;
 
   function isConnect
+    "Checks if an equation is a connect equation."
     input Equation eq;
     output Boolean isConnect;
   algorithm
@@ -1189,6 +1191,21 @@ public
     end match;
   end isConnect;
 
+  function isConnection
+    "Checks if an equation is a connect equation or a Connections.* call."
+    input Equation eq;
+    output Boolean res;
+  protected
+    Call call;
+  algorithm
+    res := match eq
+      case Equation.CONNECT() then true;
+      case Equation.NORETCALL(exp = Expression.CALL(call = call))
+        then Call.functionNameFirst(call) == "Connections";
+      else false;
+    end match;
+  end isConnection;
+
   function sizeOfList
     input list<Equation> eqs;
     output Integer size = 0;

OMCompiler/Compiler/NFFrontEnd/NFFlatten.mo

@@ -1708,7 +1708,7 @@ protected
   InstNode scope;
 algorithm
   Equation.IF(branches = branches, scope = scope, source = src) := eq;
-  has_connect := Equation.contains(eq, isConnectEq);
+  has_connect := Equation.contains(eq, Equation.isConnection);
 
   // Print errors for unbound constants/parameters if the if-equation contains
   // connects, since we must select a branch in that case.
@@ -1792,21 +1792,6 @@ algorithm
   end if;
 end flattenIfEquation;
 
-function isConnectEq
-  input Equation eq;
-  output Boolean isConnect;
-algorithm
-  isConnect := match eq
-    local
-      Function fn;
-
-    case Equation.CONNECT() then true;
-    case Equation.NORETCALL(exp = Expression.CALL(call = Call.TYPED_CALL(fn = fn)))
-      then AbsynUtil.pathFirstIdent(Function.name(fn)) == "Connections";
-    else false;
-  end match;
-end isConnectEq;
-
 function flattenEqBranch
   input output Equation.Branch branch;
   input Prefix prefix;

OMCompiler/Compiler/NFFrontEnd/NFStructural.mo

@@ -58,11 +58,15 @@ public
     output Boolean isStructural;
   protected
     Boolean is_fixed;
+    Binding binding;
   algorithm
     if compAttrs.variability <> Variability.PARAMETER then
       // Only parameters can be structural.
       isStructural := false;
     elseif compEval or parentEval then
+      binding := if Binding.isBound(compBinding) then
+        compBinding else Component.getTypeAttributeBinding(component, "start");
+
       // If the component or any of its parents has an Evaluate=true annotation
       // we should probably evaluate the parameter, which we do by marking it as
       // structural.
@@ -72,7 +76,7 @@ public
       elseif Component.isExternalObject(component) then
         // Except external objects.
         isStructural := false;
-      elseif not InstNode.hasBinding(compNode) then
+      elseif not (Binding.isBound(binding) or InstNode.hasBinding(compNode)) then
         // Except parameters with no bindings.
         if not parentEval and not Flags.getConfigBool(Flags.CHECK_MODEL) then
           // Print a warning if a parameter has an Evaluate=true annotation but no binding.
@@ -81,7 +85,7 @@ public
         end if;
 
         isStructural := false;
-      elseif isBindingNotFixed(compBinding, requireFinal = false) then
+      elseif isBindingNotFixed(binding, requireFinal = false) then
         // Except parameters that depend on non-fixed parameters.
         isStructural := false;
       else
@@ -92,7 +96,7 @@ public
     //  // If a parameter is fixed and final we might also want to evaluate it,
     //  // since its binding can't be modified. But only if all parameters it
     //  // depends on are also fixed and final.
-    //  if Binding.isUnbound(compBinding) or isBindingNotFixed(compBinding, requireFinal = true) then
+    //  if Binding.isUnbound(binding) or isBindingNotFixed(binding, requireFinal = true) then
     //    isStructural := false;
     //  else
     //    isStructural := true;
@@ -143,7 +147,8 @@ public
         if InstNode.isComponent(parent) and InstNode.isRecord(parent) then
           isNotFixed := isComponentBindingNotFixed(InstNode.component(parent), parent, requireFinal, maxDepth, true);
         else
-          isNotFixed := true;
+          binding := Component.getTypeAttributeBinding(component, "start");
+          isNotFixed := isBindingNotFixed(binding, requireFinal, maxDepth);
         end if;
       end if;
     else

OMCompiler/Compiler/NFFrontEnd/NFTyping.mo

@@ -2988,6 +2988,10 @@ algorithm
         e1 := typeIterator(eq.iterator, e1, context, structural = true);
         next_context := InstContext.set(context, NFInstContext.FOR);
         body := list(typeEquation(e, next_context) for e in eq.body);
+
+        if Equation.containsList(body, Equation.isConnection) then
+          Structural.markExp(e1);
+        end if;
       then
         Equation.FOR(eq.iterator, SOME(e1), body, eq.scope, eq.source);
 
@@ -3497,7 +3501,8 @@ algorithm
       // connections in the branch, mark the context so we can check that when
       // typing the body of the branch.
       next_context := InstContext.set(next_context, NFInstContext.NONEXPANDABLE);
-    elseif var == Variability.PARAMETER and accum_var <= Variability.PARAMETER then
+    elseif var == Variability.PARAMETER and
+           (accum_var <= Variability.PARAMETER or Equation.containsList(eql, Equation.isConnection)) then
       // If all conditions up to and including this one are parameter
       // expressions, consider the condition to be structural.
       var := Variability.STRUCTURAL_PARAMETER;

testsuite/flattening/modelica/scodeinst/ForConnect2.mo

@@ -0,0 +1,51 @@
+// name: ForConnect2
+// keywords:
+// status: correct
+// cflags: -d=newInst
+//
+//
+
+connector C
+  Real e;
+  flow Real f;
+end C;
+
+model ForConnect2
+  C c1[3], c2[3];
+  parameter Integer n(start = 3);
+equation
+  for i in 1:n loop
+    connect(c1[i], c2[i]);
+  end for;
+end ForConnect2;
+
+// Result:
+// class ForConnect2
+//   Real c1[1].e;
+//   Real c1[1].f;
+//   Real c1[2].e;
+//   Real c1[2].f;
+//   Real c1[3].e;
+//   Real c1[3].f;
+//   Real c2[1].e;
+//   Real c2[1].f;
+//   Real c2[2].e;
+//   Real c2[2].f;
+//   Real c2[3].e;
+//   Real c2[3].f;
+//   final parameter Integer n(start = 3);
+// equation
+//   c1[1].e = c2[1].e;
+//   (-c1[1].f) - c2[1].f = 0.0;
+//   c1[2].e = c2[2].e;
+//   (-c1[2].f) - c2[2].f = 0.0;
+//   c1[3].e = c2[3].e;
+//   (-c1[3].f) - c2[3].f = 0.0;
+//   c1[1].f = 0.0;
+//   c1[2].f = 0.0;
+//   c1[3].f = 0.0;
+//   c2[1].f = 0.0;
+//   c2[2].f = 0.0;
+//   c2[3].f = 0.0;
+// end ForConnect2;
+// endResult

testsuite/flattening/modelica/scodeinst/IfConnect4.mo

@@ -0,0 +1,35 @@
+// name: IfConnect4
+// keywords:
+// status: correct
+// cflags: -d=newInst
+//
+//
+
+connector C
+  Real e;
+  flow Real f;
+end C;
+
+model IfConnect4
+  parameter Boolean b(start = true);
+  C c1, c2;
+equation
+  if b then
+    connect(c1, c2);
+  end if;
+end IfConnect4;
+
+// Result:
+// class IfConnect4
+//   final parameter Boolean b(start = true);
+//   Real c1.e;
+//   Real c1.f;
+//   Real c2.e;
+//   Real c2.f;
+// equation
+//   c1.e = c2.e;
+//   (-c1.f) - c2.f = 0.0;
+//   c1.f = 0.0;
+//   c2.f = 0.0;
+// end IfConnect4;
+// endResult

testsuite/flattening/modelica/scodeinst/Makefile

@@ -514,6 +514,7 @@ Final5.mo \
 Final6.mo \
 Final7.mo \
 ForConnect1.mo \
+ForConnect2.mo \
 ForEquation1.mo \
 ForEquation2.mo \
 ForEquation3.mo \
@@ -705,6 +706,7 @@ FunctionUnitialized4.mo \
 IfConnect1.mo \
 IfConnect2.mo \
 IfConnect3.mo \
+IfConnect4.mo \
 IfEquation1.mo \
 IfEquation2.mo \
 IfEquation3.mo \