Runtime: Finish removing the 'extra argument' notion

Author: slavapestov

include/swift/ABI/MetadataValues.h

@@ -1855,28 +1855,23 @@ enum class GenericParamKind : uint8_t {
 };
 
 class GenericParamDescriptor {
+  /// Don't set 0x40 for compatibility with pre-Swift 5.8 runtimes
   uint8_t Value;
 
   explicit constexpr GenericParamDescriptor(uint8_t Value)
     : Value(Value) {}
 public:
   constexpr GenericParamDescriptor(GenericParamKind kind,
-                                   bool hasKeyArgument,
-                                   bool hasExtraArgument)
+                                   bool hasKeyArgument)
     : GenericParamDescriptor(GenericParamDescriptor(0)
                          .withKind(kind)
-                         .withKeyArgument(hasKeyArgument)
-                         .withExtraArgument(hasExtraArgument))
+                         .withKeyArgument(hasKeyArgument))
   {}
 
   constexpr bool hasKeyArgument() const {
     return (Value & 0x80u) != 0;
   }
 
-  constexpr bool hasExtraArgument() const {
-    return (Value & 0x40u) != 0;
-  }
-
   constexpr GenericParamKind getKind() const {
     return GenericParamKind(Value & 0x3Fu);
   }
@@ -1887,12 +1882,6 @@ class GenericParamDescriptor {
       | (hasKeyArgument ? 0x80u : 0));
   }
 
-  constexpr GenericParamDescriptor
-  withExtraArgument(bool hasExtraArgument) const {
-    return GenericParamDescriptor((Value & 0xBFu)
-      | (hasExtraArgument ? 0x40u : 0));
-  }
-
   constexpr GenericParamDescriptor withKind(GenericParamKind kind) const {
     return assert((uint8_t(kind) & 0x3Fu) == uint8_t(kind)),
       GenericParamDescriptor((Value & 0xC0u) | uint8_t(kind));
@@ -1914,8 +1903,7 @@ class GenericParamDescriptor {
   /// The default parameter descriptor for an implicit parameter.
   static constexpr GenericParamDescriptor implicit() {
     return GenericParamDescriptor(GenericParamKind::Type,
-                                  /*key argument*/ true,
-                                  /*extra argument*/ false);
+                                  /*key argument*/ true);
   }
 };
 
@@ -1952,30 +1940,25 @@ enum class GenericRequirementKind : uint8_t {
 };
 
 class GenericRequirementFlags {
+  /// Don't set 0x40 for compatibility with pre-Swift 5.8 runtimes
   uint32_t Value;
 
   explicit constexpr GenericRequirementFlags(uint32_t Value)
     : Value(Value) {}
 public:
   constexpr GenericRequirementFlags(GenericRequirementKind kind,
                                     bool hasKeyArgument,
-                                    bool hasExtraArgument,
                                     bool isPackRequirement)
     : GenericRequirementFlags(GenericRequirementFlags(0)
                          .withKind(kind)
                          .withKeyArgument(hasKeyArgument)
-                         .withExtraArgument(hasExtraArgument)
                          .withPackRequirement(isPackRequirement))
   {}
 
   constexpr bool hasKeyArgument() const {
     return (Value & 0x80u) != 0;
   }
 
-  constexpr bool hasExtraArgument() const {
-    return (Value & 0x40u) != 0;
-  }
-
   /// If this is true, the subject type of the requirement is a pack.
   /// When the requirement is a conformance requirement, the corresponding
   /// entry in the generic arguments array becomes a TargetWitnessTablePack.
@@ -1993,12 +1976,6 @@ class GenericRequirementFlags {
       | (hasKeyArgument ? 0x80u : 0));
   }
 
-  constexpr GenericRequirementFlags
-  withExtraArgument(bool hasExtraArgument) const {
-    return GenericRequirementFlags((Value & 0xBFu)
-      | (hasExtraArgument ? 0x40u : 0));
-  }
-
   constexpr GenericRequirementFlags
   withPackRequirement(bool isPackRequirement) const {
     return GenericRequirementFlags((Value & 0xBFu)

include/swift/Remote/MetadataReader.h

@@ -3026,11 +3026,6 @@ class MetadataReader {
     for (auto param : generics->getGenericParams()) {
       switch (param.getKind()) {
       case GenericParamKind::Type:
-        // We don't know about type parameters with extra arguments.
-        if (param.hasExtraArgument()) {
-          return {};
-        }
-        
         // The type should have a key argument unless it's been same-typed
         // to another type.
         if (param.hasKeyArgument()) {
@@ -3057,6 +3052,9 @@ class MetadataReader {
         }
         break;
 
+      case GenericParamKind::TypePack:
+        assert(false && "Packs not supported here yet");
+
       default:
         // We don't know about this kind of parameter.
         return {};