[CSFix] Adjust tuple splat fix attempt to record a fix and return a boolean

Author: xedin

lib/Sema/CSFix.cpp

@@ -662,18 +662,18 @@ bool AllowTupleSplatForSingleParameter::diagnose(Expr *root, bool asNote) const
   return false;
 }
 
-AllowTupleSplatForSingleParameter *AllowTupleSplatForSingleParameter::attempt(
+bool AllowTupleSplatForSingleParameter::attempt(
     ConstraintSystem &cs, SmallVectorImpl<Param> &args, ArrayRef<Param> params,
     SmallVectorImpl<SmallVector<unsigned, 1>> &bindings,
     ConstraintLocatorBuilder locator) {
   if (params.size() != 1 || args.size() <= 1)
-    return nullptr;
+    return true;
 
   const auto &param = params.front();
 
   auto *paramTy = param.getOldType()->getAs<TupleType>();
   if (!paramTy || paramTy->getNumElements() != args.size())
-    return nullptr;
+    return true;
 
   SmallVector<TupleTypeElt, 4> argElts;
   for (const auto &arg : args) {
@@ -689,6 +689,8 @@ AllowTupleSplatForSingleParameter *AllowTupleSplatForSingleParameter::attempt(
   args.clear();
   args.push_back(AnyFunctionType::Param(newArgType, param.getLabel()));
 
-  return new (cs.getAllocator()) AllowTupleSplatForSingleParameter(
+  auto *fix = new (cs.getAllocator()) AllowTupleSplatForSingleParameter(
       cs, paramTy, cs.getConstraintLocator(locator));
+
+  return cs.recordFix(fix);
 }

lib/Sema/CSFix.h

@@ -1203,11 +1203,13 @@ class AllowTupleSplatForSingleParameter final : public ConstraintFix {
 
   bool diagnose(Expr *root, bool asNote = false) const override;
 
-  static AllowTupleSplatForSingleParameter *
-  attempt(ConstraintSystem &cs, SmallVectorImpl<Param> &args,
-          ArrayRef<Param> params,
-          SmallVectorImpl<SmallVector<unsigned, 1>> &bindings,
-          ConstraintLocatorBuilder locator);
+  /// Apply this fix to given arguments/parameters and return `true`
+  /// this fix is not applicable and solver can't continue, `false`
+  /// otherwise.
+  static bool attempt(ConstraintSystem &cs, SmallVectorImpl<Param> &args,
+                      ArrayRef<Param> params,
+                      SmallVectorImpl<SmallVector<unsigned, 1>> &bindings,
+                      ConstraintLocatorBuilder locator);
 };
 
 } // end namespace constraints

lib/Sema/CSSimplify.cpp

@@ -953,10 +953,8 @@ ConstraintSystem::TypeMatchResult constraints::matchCallArguments(
     if (!cs.shouldAttemptFixes())
       return cs.getTypeMatchFailure(locator);
 
-    auto *fix = AllowTupleSplatForSingleParameter::attempt(
-        cs, argsWithLabels, params, parameterBindings, locator);
-
-    if (!fix || cs.recordFix(fix))
+    if (AllowTupleSplatForSingleParameter::attempt(cs, argsWithLabels, params,
+                                                   parameterBindings, locator))
       return cs.getTypeMatchFailure(locator);
   }