[AST/Serialization] Remove isCallerIsolated bit from ParamDecl

This was used primarily by the printer and doesn't work when
`nonisolated(nonsending)` is inferred, so let's remove it.

Author: xedin

include/swift/AST/Decl.h

@@ -7334,18 +7334,6 @@ class ParamDecl : public VarDecl {
       removeFlag(Flag::IsSending);
   }
 
-  /// Whether or not this parameter is marked with 'nonisolated(nonsending)'.
-  bool isCallerIsolated() const {
-    return getOptions().contains(Flag::IsCallerIsolated);
-  }
-
-  void setCallerIsolated(bool value = true) {
-    if (value)
-      addFlag(Flag::IsCallerIsolated);
-    else
-      removeFlag(Flag::IsCallerIsolated);
-  }
-
   /// Whether or not this parameter is marked with '@_addressable'.
   bool isAddressable() const {
     return getOptions().contains(Flag::IsAddressable);

lib/AST/Decl.cpp

@@ -9204,7 +9204,6 @@ void ParamDecl::setTypeRepr(TypeRepr *repr) {
 
       if (auto *callerIsolated =
               dyn_cast<CallerIsolatedTypeRepr>(unwrappedType)) {
-        setCallerIsolated(true);
         unwrappedType = callerIsolated->getBase();
         continue;
       }

lib/Serialization/Deserialization.cpp

@@ -4222,7 +4222,6 @@ class DeclDeserializer {
     bool isIsolated;
     bool isCompileTimeLiteral, isConstValue;
     bool isSending;
-    bool isCallerIsolated;
     bool isAddressable;
     uint8_t rawDefaultArg;
     TypeID defaultExprType;
@@ -4236,7 +4235,6 @@ class DeclDeserializer {
                                          isCompileTimeLiteral,
                                          isConstValue,
                                          isSending,
-                                         isCallerIsolated,
                                          isAddressable,
                                          rawDefaultArg,
                                          defaultExprType,
@@ -4283,7 +4281,6 @@ class DeclDeserializer {
     param->setCompileTimeLiteral(isCompileTimeLiteral);
     param->setConstValue(isConstValue);
     param->setSending(isSending);
-    param->setCallerIsolated(isCallerIsolated);
     param->setAddressable(isAddressable);
 
     // Decode the default argument kind.

lib/Serialization/ModuleFormat.h

@@ -58,7 +58,7 @@ const uint16_t SWIFTMODULE_VERSION_MAJOR = 0;
 /// describe what change you made. The content of this comment isn't important;
 /// it just ensures a conflict if two people change the module format.
 /// Don't worry about adhering to the 80-column limit for this line.
-const uint16_t SWIFTMODULE_VERSION_MINOR = 973; // @export attribute
+const uint16_t SWIFTMODULE_VERSION_MINOR = 974; // remove 'isCallerIsolated' bit from ParamDecl
 
 /// A standard hash seed used for all string hashes in a serialized module.
 ///
@@ -1763,7 +1763,6 @@ namespace decls_block {
     BCFixed<1>,              // isCompileTimeLiteral?
     BCFixed<1>,              // isConst?
     BCFixed<1>,              // isSending?
-    BCFixed<1>,              // isCallerIsolated?
     BCFixed<1>,              // isAddressable?
     DefaultArgumentField,    // default argument kind
     TypeIDField,             // default argument type

lib/Serialization/Serialization.cpp

@@ -4808,7 +4808,6 @@ class Serializer::DeclSerializer : public DeclVisitor<DeclSerializer> {
         param->isCompileTimeLiteral(),
         param->isConstVal(),
         param->isSending(),
-        param->isCallerIsolated(),
         param->isAddressable(),
         getRawStableDefaultArgumentKind(argKind),
         S.addTypeRef(defaultExprType),