Re-instate awful AST dumping hack

Author: DougGregor

lib/AST/ASTDumper.cpp

@@ -1747,6 +1747,11 @@ void swift::printContext(raw_ostream &os, DeclContext *dc) {
         << "autoclosure discriminator=";
     }
 
+    // If we aren't printing to standard error or the debugger output stream,
+    // this client expects to see the computed discriminator. Compute it now.
+    if (&os != &llvm::errs() && &os != &llvm::dbgs())
+      (void)ACE->getDiscriminator();
+
     PrintWithColorRAII(os, DiscriminatorColor) << ACE->getRawDiscriminator();
     break;
   }
@@ -2777,6 +2782,12 @@ class PrintExpr : public ExprVisitor<PrintExpr, void, StringRef>,
   void printClosure(AbstractClosureExpr *E, char const *name,
                                   StringRef label) {
     printCommon(E, name, label);
+
+    // If we aren't printing to standard error or the debugger output stream,
+    // this client expects to see the computed discriminator. Compute it now.
+    if (hasNonStandardOutput())
+      (void)E->getDiscriminator();
+
     printField(E->getRawDiscriminator(), "discriminator", DiscriminatorColor);
 
     switch (auto isolation = E->getActorIsolation()) {