Merge pull request #19422 from xedin/create-scope-while-taking

[CSStep] Allocate component scopes only if siblings didn't fail

Author: xedin

lib/Sema/CSStep.cpp

@@ -253,6 +253,9 @@ StepResult ComponentStep::take(bool prevFailed) {
   if (prevFailed || CS.getExpressionTooComplex(Solutions))
     return done(/*isSuccess=*/false);
 
+  // Setup active scope, only if previous component didn't fail.
+  setupScope();
+
   /// Try to figure out what this step is going to be,
   /// after the scope has been established.
   auto *disjunction = CS.selectDisjunction();

lib/Sema/CSStep.h

@@ -373,7 +373,18 @@ class ComponentStep final : public SolverStep {
     OrphanedConstraint = constraint;
   }
 
-  void setup() override {
+  StepResult take(bool prevFailed) override;
+  StepResult resume(bool prevFailed) override;
+
+  // The number of disjunction constraints associated with this component.
+  unsigned disjunctionCount() const { return NumDisjunctions; }
+
+  void print(llvm::raw_ostream &Out) override {
+    Out << "ComponentStep with at #" << Index << '\n';
+  }
+
+private:
+  void setupScope() {
     // If this is a single component, there is no need
     // to preliminary modify constraint system or log anything.
     if (IsSingle)
@@ -387,16 +398,6 @@ class ComponentStep final : public SolverStep {
     // let's return it ot the graph.
     CS.CG.setOrphanedConstraint(OrphanedConstraint);
   }
-
-  StepResult take(bool prevFailed) override;
-  StepResult resume(bool prevFailed) override;
-
-  // The number of disjunction constraints associated with this component.
-  unsigned disjunctionCount() const { return NumDisjunctions; }
-
-  void print(llvm::raw_ostream &Out) override {
-    Out << "ComponentStep with at #" << Index << '\n';
-  }
 };
 
 template <typename P> class BindingStep : public SolverStep {