Sema: Split up BindingSet::inferTransitiveBindings() into three methods

Author: slavapestov

include/swift/Sema/CSBindings.h

@@ -540,6 +540,8 @@ class BindingSet {
   /// Check if this binding is favored over a conjunction.
   bool favoredOverConjunction(Constraint *conjunction) const;
 
+  void inferTransitiveKeyPathBindings();
+
   /// Detect `subtype` relationship between two type variables and
   /// attempt to infer supertype bindings transitively e.g.
   ///
@@ -549,9 +551,9 @@ class BindingSet {
   ///
   /// \param inferredBindings The set of all bindings inferred for type
   /// variables in the workset.
-  void inferTransitiveBindings();
+  void inferTransitiveSupertypeBindings();
 
-  void inferTransitiveKeyPathBindings();
+  void inferTransitiveUnresolvedMemberRefBindings();
 
   /// Detect subtype, conversion or equivalence relationship
   /// between two type variables and attempt to propagate protocol

lib/Sema/CSBindings.cpp

@@ -558,9 +558,7 @@ void BindingSet::inferTransitiveKeyPathBindings() {
   }
 }
 
-void BindingSet::inferTransitiveBindings() {
-  inferTransitiveKeyPathBindings();
-
+void BindingSet::inferTransitiveSupertypeBindings() {
   for (const auto &entry : Info.SupertypeOf) {
     auto &node = CS.getConstraintGraph()[entry.first];
     if (!node.hasBindingSet())
@@ -626,7 +624,9 @@ void BindingSet::inferTransitiveBindings() {
                  /*isTransitive=*/true);
     }
   }
+}
 
+void BindingSet::inferTransitiveUnresolvedMemberRefBindings() {
   if (!hasViableBindings()) {
     if (auto *locator = TypeVar->getImpl().getLocator()) {
       if (locator->isLastElement<LocatorPathElt::MemberRefBase>()) {
@@ -1193,7 +1193,9 @@ std::optional<BindingSet> ConstraintSystem::determineBestBindings(
     // produce a default type.
     bool isViable = isViableForRanking(bindings);
 
-    bindings.inferTransitiveBindings();
+    bindings.inferTransitiveKeyPathBindings();
+    bindings.inferTransitiveSupertypeBindings();
+    bindings.inferTransitiveUnresolvedMemberRefBindings();
 
     if (!bindings.finalizeKeyPathBindings())
       continue;

unittests/Sema/BindingInferenceTests.cpp

@@ -125,7 +125,9 @@ TEST_F(SemaTest, TestIntLiteralBindingInference) {
 
     cs.getConstraintGraph()[floatLiteralTy].initBindingSet();
 
-    bindings.inferTransitiveBindings();
+    bindings.inferTransitiveKeyPathBindings();
+    bindings.inferTransitiveSupertypeBindings();
+    bindings.inferTransitiveUnresolvedMemberRefBindings();
     (void) bindings.finalizeKeyPathBindings();
     bindings.finalizeUnresolvedMemberChainResult();
     bindings.determineLiteralCoverage();

unittests/Sema/SemaFixture.cpp

@@ -141,11 +141,14 @@ BindingSet SemaTest::inferBindings(ConstraintSystem &cs,
 
     auto &bindings = node.getBindingSet();
 
-    // FIXME: This is also called in inferTransitiveBindings(), why do we need
-    // to call it again?
+    // FIXME: This is also called in inferTransitiveUnresolvedMemberRefBindings(),
+    // why do we need to call it here too?
     bindings.inferTransitiveProtocolRequirements();
 
-    bindings.inferTransitiveBindings();
+    bindings.inferTransitiveKeyPathBindings();
+    bindings.inferTransitiveSupertypeBindings();
+    bindings.inferTransitiveUnresolvedMemberRefBindings();
+
     (void) bindings.finalizeKeyPathBindings();
     bindings.finalizeUnresolvedMemberChainResult();
     bindings.determineLiteralCoverage();