[ConstraintSystem] Audit remaining arguments for packElementOpener to type

resolution.

Author: hborla

lib/Sema/CSSolver.cpp

@@ -1191,7 +1191,6 @@ void ConstraintSystem::shrink(Expr *expr) {
                 // let foo: [Array<Float>] = [[0], [1], [2]] as [Array]
                 // let foo: [Array<Float>] = [[0], [1], [2]] as [Array<_>]
                 /*unboundTyOpener*/ nullptr, /*placeholderHandler*/ nullptr,
-                // FIXME: Open pack elements with a PackElementOf constraint.
                 /*packElementOpener*/ nullptr);
 
             // Looks like coercion type is invalid, let's skip this sub-tree.

lib/Sema/PreCheckExpr.cpp

@@ -1466,7 +1466,7 @@ TypeExpr *PreCheckExpression::simplifyNestedTypeExpr(UnresolvedDotExpr *UDE) {
         // FIXME: Don't let placeholder types escape type resolution.
         // For now, just return the placeholder type.
         PlaceholderType::get,
-        // FIXME: Open pack elements with a PackElementOf constraint.
+        // TypeExpr pack elements are opened in CSGen.
         /*packElementOpener*/ nullptr);
 
     if (BaseTy->mayHaveMembers()) {
@@ -2221,7 +2221,7 @@ Expr *PreCheckExpression::simplifyTypeConstructionWithLiteralArg(Expr *E) {
         // FIXME: Don't let placeholder types escape type resolution.
         // For now, just return the placeholder type.
         PlaceholderType::get,
-        // FIXME: Open pack elements with a PackElementOf constraint.
+        // Pack elements for CoerceExprs are opened in CSGen.
         /*packElementOpener*/ nullptr);
 
     if (result->hasError())