Add support for noinit remote variables.

compiler/passes/convert-uast.cpp

@@ -2298,7 +2298,7 @@ struct Converter final : UastConverter {
     // Field multi-decl desugaring happens later in build.cpp and produces
     // different code; don't do redundant work here.
     bool isField = parsing::idIsField(context, node->id());
-    if (!isField) {
+    if (isField) {
       // post-parse checks should rule this out
       CHPL_ASSERT(!node->destination());
     }
@@ -3523,13 +3523,16 @@ struct Converter final : UastConverter {
       if (auto prevInitExpr = multiState->prevInitExpr) {
         Expr* replaceWith;
         if (prevInitExpr->isNoInitExpr()) {
-          replaceWith = prevInitExpr->copy();
+          // for remote variables, don't bother trying to replace 'noinit',
+          // since we already threw it away and selected a different overload of
+          // buildRemoteWrapper.
+          replaceWith = isRemote ? nullptr : prevInitExpr->copy();
         } else if (typeExpr) {
           replaceWith = new CallExpr("chpl__readXX", new SymExpr(varSym));
         } else {
           replaceWith = new SymExpr(varSym);
         }
-        multiState->replaceInitExpr(replaceWith);
+        if (replaceWith) multiState->replaceInitExpr(replaceWith);
         initExpr = prevInitExpr;
       }
 
@@ -3551,7 +3554,13 @@ struct Converter final : UastConverter {
       wrapperCall->insertAtTail(destinationExpr ? destinationExpr : new SymExpr(multiState->localeTemp));
 
       if (typeExpr) wrapperCall->insertAtTail(typeExpr);
-      if (initExpr) wrapperCall->insertAtTail(new CallExpr(PRIM_CREATE_THUNK, initExpr));
+      if (initExpr) {
+        if (initExpr->isNoInitExpr()) {
+          wrapperCall->insertAtTail(new SymExpr(dtVoid->symbol));
+        } else {
+          wrapperCall->insertAtTail(new CallExpr(PRIM_CREATE_THUNK, initExpr));
+        }
+      }
       auto wrapperDef = new DefExpr(wrapper, wrapperCall);
 
       auto wrapperGet = new CallExpr(".", new SymExpr(wrapper), new_CStringSymbol("get"));

modules/internal/ChapelRemoteVars.chpl

@@ -24,6 +24,11 @@ module ChapelRemoteVars {
 
   class _remoteVarContainer {
     var containedValue;
+
+    proc type _noinit(type containedValueType) {
+      var tmp: containedValueType = noinit;
+      return new _remoteVarContainer(tmp);
+    }
   }
 
   record _remoteVarWrapper {
@@ -78,6 +83,16 @@ module ChapelRemoteVars {
     return new _remoteVarWrapper(try! c : owned _remoteVarContainer(inType));
   }
 
+  @unstable("remote variables are unstable")
+  inline proc chpl__buildRemoteWrapper(const ref loc, type inType, type noinitMarker) where noinitMarker == void {
+    // This is a special case to create a noinit remote variable.
+    // We use a specific overload of the _remoteVarContainer constructor
+    // which accepts a type and uses noinit.
+    var c: owned _remoteVarContainer(inType)?;
+    on loc do c = _remoteVarContainer._noinit(inType);
+    return new _remoteVarWrapper(try! c : owned _remoteVarContainer(inType));
+  }
+
   @unstable("remote variables are unstable")
   inline proc chpl__buildRemoteWrapper(const ref loc, type inType, in tr: _thunkRecord) {
     var c: owned _remoteVarContainer(inType)?;

test/variables/remote/noinit-vars.chpl

@@ -0,0 +1,15 @@
+record R {
+  proc init() {
+    writeln("R.init");
+  }
+}
+
+writeln("yesinit");
+on Locales[0] var A: [0..0] R;
+writeln("noinit");
+on Locales[0] var B: [0..0] R = noinit;
+
+writeln("yesinit");
+on Locales[0] var C, D: [0..0] R;
+writeln("noinit");
+on Locales[0] var E, F: [0..0] R = noinit;

test/variables/remote/noinit-vars.good

@@ -0,0 +1,7 @@
+yesinit
+R.init
+noinit
+yesinit
+R.init
+R.init
+noinit