Sema: Extract coalesceIntegerAndFloatLiteralRequirements() from BindingSet::BindingSet, and do it at the end

Author: slavapestov

include/swift/Sema/CSBindings.h

@@ -574,6 +574,11 @@ class BindingSet {
   /// requirements down the subtype or equivalence chain.
   void inferTransitiveProtocolRequirements();
 
+  /// Try to coalesce integer and floating point literal protocols
+  /// if they appear together because the only possible default type that
+  /// could satisfy both requirements is `Double`.
+  void coalesceIntegerAndFloatLiteralRequirements();
+
   /// Check whether the given binding set covers any of the literal protocols
   /// associated with this type variable. The idea is that if a type variable
   /// has a binding like Int and also it has a conformance requirement to

lib/Sema/CSBindings.cpp

@@ -1031,28 +1031,32 @@ void BindingSet::determineLiteralCoverage() {
   }
 }
 
-void BindingSet::addLiteralRequirement(Constraint *constraint) {
-  auto *protocol = constraint->getProtocol();
+void BindingSet::coalesceIntegerAndFloatLiteralRequirements() {
+  for (const auto &pair : Literals) {
+    auto *protocol = pair.first;
 
-  // Let's try to coalesce integer and floating point literal protocols
-  // if they appear together because the only possible default type that
-  // could satisfy both requirements is `Double`.
-  {
     if (protocol->isSpecificProtocol(
             KnownProtocolKind::ExpressibleByIntegerLiteral)) {
       auto *floatLiteral = CS.getASTContext().getProtocol(
           KnownProtocolKind::ExpressibleByFloatLiteral);
-      if (Literals.count(floatLiteral))
+      if (Literals.count(floatLiteral)) {
+        Literals.erase(protocol);
         return;
+      }
     }
 
     if (protocol->isSpecificProtocol(
             KnownProtocolKind::ExpressibleByFloatLiteral)) {
       auto *intLiteral = CS.getASTContext().getProtocol(
           KnownProtocolKind::ExpressibleByIntegerLiteral);
       Literals.erase(intLiteral);
+      return;
     }
   }
+}
+
+void BindingSet::addLiteralRequirement(Constraint *constraint) {
+  auto *protocol = constraint->getProtocol();
 
   if (Literals.count(protocol) > 0)
     return;
@@ -1235,6 +1239,9 @@ const BindingSet *ConstraintSystem::determineBestBindings(
       bestBindings = &bindings;
   }
 
+  if (bestBindings)
+    bestBindings->coalesceIntegerAndFloatLiteralRequirements();
+
   return bestBindings;
 }
 
@@ -1667,6 +1674,7 @@ BindingSet ConstraintSystem::getBindingsFor(TypeVariableType *typeVar) {
   (void) bindings.finalizeKeyPathBindings();
   bindings.finalizeUnresolvedMemberChainResult();
   bindings.determineLiteralCoverage();
+  bindings.coalesceIntegerAndFloatLiteralRequirements();
 
   return bindings;
 }