[Sema] std::function -> llvm::function_ref for some non-escaping params.

Author: huonw

lib/Sema/TypeCheckNameLookup.cpp

@@ -27,7 +27,7 @@
 using namespace swift;
 
 void LookupResult::filter(
-    const std::function<bool(LookupResultEntry, bool)> &pred) {
+    llvm::function_ref<bool(LookupResultEntry, bool)> pred) {
   size_t index = 0;
   size_t originalFirstOuter = IndexOfFirstOuterResult;
   Results.erase(std::remove_if(Results.begin(), Results.end(),

lib/Sema/TypeCheckProtocol.cpp

@@ -351,14 +351,14 @@ RequirementMatch
 swift::matchWitness(
              TypeChecker &tc,
              DeclContext *dc, ValueDecl *req, ValueDecl *witness,
-             const std::function<
+             llvm::function_ref<
                      std::tuple<Optional<RequirementMatch>, Type, Type>(void)> 
-               &setup,
-             const std::function<Optional<RequirementMatch>(Type, Type)> 
-               &matchTypes,
-             const std::function<
+               setup,
+             llvm::function_ref<Optional<RequirementMatch>(Type, Type)>
+               matchTypes,
+             llvm::function_ref<
                      RequirementMatch(bool, ArrayRef<OptionalAdjustment>)
-                   > &finalize) {
+                   > finalize) {
   assert(!req->isInvalid() && "Cannot have an invalid requirement here");
 
   /// Make sure the witness is of the same kind as the requirement.

lib/Sema/TypeCheckProtocol.h

@@ -830,14 +830,14 @@ class AssociatedTypeInference {
 RequirementMatch matchWitness(
              TypeChecker &tc,
              DeclContext *dc, ValueDecl *req, ValueDecl *witness,
-             const std::function<
+             llvm::function_ref<
                      std::tuple<Optional<RequirementMatch>, Type, Type>(void)>
-               &setup,
-             const std::function<Optional<RequirementMatch>(Type, Type)>
-               &matchTypes,
-             const std::function<
+               setup,
+             llvm::function_ref<Optional<RequirementMatch>(Type, Type)>
+               matchTypes,
+             llvm::function_ref<
                      RequirementMatch(bool, ArrayRef<OptionalAdjustment>)
-                   > &finalize);
+                   > finalize);
 
 RequirementMatch matchWitness(TypeChecker &tc,
                               ProtocolDecl *proto,

lib/Sema/TypeChecker.h

@@ -148,7 +148,7 @@ class LookupResult {
 
   /// Filter out any results that aren't accepted by the given predicate.
   void
-  filter(const std::function<bool(LookupResultEntry, /*isOuter*/ bool)> &pred);
+  filter(llvm::function_ref<bool(LookupResultEntry, /*isOuter*/ bool)> pred);
 };
 
 /// The result of name lookup for types.