From c47ff06a7289ec2bde4730f34b50b87d0a82ba64 Mon Sep 17 00:00:00 2001
From: Slava Pestov <spestov@apple.com>
Date: Wed, 22 Jan 2025 13:28:35 -0500
Subject: [PATCH] Sema: Tiny cleanup for matchTypes()

---
 include/swift/Sema/ConstraintSystem.h | 13 +++++-----
 lib/Sema/CSSimplify.cpp               | 34 +++++++++++++--------------
 2 files changed, 23 insertions(+), 24 deletions(-)

diff --git a/include/swift/Sema/ConstraintSystem.h b/include/swift/Sema/ConstraintSystem.h
index 1d435e6059f..189478c3184 100644
--- a/include/swift/Sema/ConstraintSystem.h
+++ b/include/swift/Sema/ConstraintSystem.h
@@ -4608,16 +4608,15 @@ public:
     inline bool isFailure() const { return Kind == SolutionKind::Error; }
     inline bool isAmbiguous() const { return Kind == SolutionKind::Unsolved; }
 
-    static TypeMatchResult success(ConstraintSystem &cs) {
+    static TypeMatchResult success() {
       return {SolutionKind::Solved};
     }
 
-    static TypeMatchResult failure(ConstraintSystem &cs,
-                                   ConstraintLocatorBuilder location) {
+    static TypeMatchResult failure() {
       return {SolutionKind::Error};
     }
 
-    static TypeMatchResult ambiguous(ConstraintSystem &cs) {
+    static TypeMatchResult ambiguous() {
       return {SolutionKind::Unsolved};
     }
 
@@ -4722,15 +4721,15 @@ public: // FIXME: public due to statics in CSSimplify.cpp
                              ConstraintLocatorBuilder locator);
 
   TypeMatchResult getTypeMatchSuccess() {
-    return TypeMatchResult::success(*this);
+    return TypeMatchResult::success();
   }
 
   TypeMatchResult getTypeMatchFailure(ConstraintLocatorBuilder locator) {
-    return TypeMatchResult::failure(*this, locator);
+    return TypeMatchResult::failure();
   }
 
   TypeMatchResult getTypeMatchAmbiguous() {
-    return TypeMatchResult::ambiguous(*this);
+    return TypeMatchResult::ambiguous();
   }
 
 public:
diff --git a/lib/Sema/CSSimplify.cpp b/lib/Sema/CSSimplify.cpp
index dbb0de6034d..3a57ef42662 100644
--- a/lib/Sema/CSSimplify.cpp
+++ b/lib/Sema/CSSimplify.cpp
@@ -7646,6 +7646,22 @@ ConstraintSystem::matchTypes(Type type1, Type type2, ConstraintKind kind,
     }
   }
 
+  if (kind == ConstraintKind::BindToPointerType) {
+    if (desugar2->isEqual(getASTContext().TheEmptyTupleType))
+      return getTypeMatchSuccess();
+  }
+
+  if (kind == ConstraintKind::BindParam) {
+    if (auto *iot = dyn_cast<InOutType>(desugar1)) {
+      if (auto *lvt = dyn_cast<LValueType>(desugar2)) {
+        return matchTypes(iot->getObjectType(), lvt->getObjectType(),
+                          ConstraintKind::Bind, subflags,
+                          locator.withPathElement(
+                            ConstraintLocator::LValueConversion));
+      }
+    }
+  }
+
   if (kind >= ConstraintKind::Conversion) {
     // An lvalue of type T1 can be converted to a value of type T2 so long as
     // T1 is convertible to T2 (by loading the value).  Note that we cannot get
@@ -7777,7 +7793,7 @@ ConstraintSystem::matchTypes(Type type1, Type type2, ConstraintKind kind,
     }
 
     // Special implicit nominal conversions.
-    if (!type1->is<LValueType>() && kind >= ConstraintKind::Subtype) {
+    if (!type1->is<LValueType>()) {
       // Array -> Array.
       if (desugar1->isArray() && desugar2->isArray()) {
         conversionsOrFixes.push_back(ConversionRestrictionKind::ArrayUpcast);
@@ -7793,11 +7809,6 @@ ConstraintSystem::matchTypes(Type type1, Type type2, ConstraintKind kind,
     }
   }
 
-  if (kind == ConstraintKind::BindToPointerType) {
-    if (desugar2->isEqual(getASTContext().TheEmptyTupleType))
-      return getTypeMatchSuccess();
-  }
-
   if (kind >= ConstraintKind::Conversion) {
     // It is never legal to form an autoclosure that results in these
     // implicit conversions to pointer types.
@@ -8054,17 +8065,6 @@ ConstraintSystem::matchTypes(Type type1, Type type2, ConstraintKind kind,
     }
   }
 
-  if (kind == ConstraintKind::BindParam) {
-    if (auto *iot = dyn_cast<InOutType>(desugar1)) {
-      if (auto *lvt = dyn_cast<LValueType>(desugar2)) {
-        return matchTypes(iot->getObjectType(), lvt->getObjectType(),
-                          ConstraintKind::Bind, subflags,
-                          locator.withPathElement(
-                            ConstraintLocator::LValueConversion));
-      }
-    }
-  }
-
   // Matching types where one side is a pack expansion and the other is not
   // means a pack expansion was used where it isn't supported.
   if (type1->is<PackExpansionType>() != type2->is<PackExpansionType>()) {