[clang][NFC] Move Sema::SkipBodyInfo into namespace scope

This makes it forward-declarable, and needed from splitting `Sema` up.

Author: Endilll

clang/include/clang/Sema/Sema.h

@@ -352,6 +352,14 @@ class PreferredTypeBuilder {
   llvm::function_ref<QualType()> ComputeType;
 };
 
+struct SkipBodyInfo {
+  SkipBodyInfo() = default;
+  bool ShouldSkip = false;
+  bool CheckSameAsPrevious = false;
+  NamedDecl *Previous = nullptr;
+  NamedDecl *New = nullptr;
+};
+
 /// Describes the result of template argument deduction.
 ///
 /// The TemplateDeductionResult enumeration describes the result of
@@ -2627,14 +2635,6 @@ class Sema final : public SemaBase {
     return Entity->getOwningModule();
   }
 
-  struct SkipBodyInfo {
-    SkipBodyInfo() = default;
-    bool ShouldSkip = false;
-    bool CheckSameAsPrevious = false;
-    NamedDecl *Previous = nullptr;
-    NamedDecl *New = nullptr;
-  };
-
   DeclGroupPtrTy ConvertDeclToDeclGroup(Decl *Ptr, Decl *OwnedType = nullptr);
 
   ParsedType getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,

clang/lib/Parse/ParseDecl.cpp

@@ -5331,7 +5331,7 @@ void Parser::ParseEnumSpecifier(SourceLocation StartLoc, DeclSpec &DS,
 
   stripTypeAttributesOffDeclSpec(attrs, DS, TUK);
 
-  Sema::SkipBodyInfo SkipBody;
+  SkipBodyInfo SkipBody;
   if (!Name && TUK == Sema::TUK_Definition && Tok.is(tok::l_brace) &&
       NextToken().is(tok::identifier))
     SkipBody = Actions.shouldSkipAnonEnumBody(getCurScope(),

clang/lib/Parse/ParseDeclCXX.cpp

@@ -2092,7 +2092,7 @@ void Parser::ParseClassSpecifier(tok::TokenKind TagTokKind,
   TypeResult TypeResult = true;      // invalid
 
   bool Owned = false;
-  Sema::SkipBodyInfo SkipBody;
+  SkipBodyInfo SkipBody;
   if (TemplateId) {
     // Explicit specialization, class template partial specialization,
     // or explicit instantiation.

clang/lib/Parse/ParseObjc.cpp

@@ -375,7 +375,7 @@ Decl *Parser::ParseObjCAtInterfaceDeclaration(SourceLocation AtLoc,
     Actions.ActOnTypedefedProtocols(protocols, protocolLocs,
                                     superClassId, superClassLoc);
 
-  Sema::SkipBodyInfo SkipBody;
+  SkipBodyInfo SkipBody;
   ObjCInterfaceDecl *ClsType = Actions.ActOnStartClassInterface(
       getCurScope(), AtLoc, nameId, nameLoc, typeParameterList, superClassId,
       superClassLoc, typeArgs,
@@ -2133,7 +2133,7 @@ Parser::ParseObjCAtProtocolDeclaration(SourceLocation AtLoc,
                                   /*consumeLastToken=*/true))
     return nullptr;
 
-  Sema::SkipBodyInfo SkipBody;
+  SkipBodyInfo SkipBody;
   ObjCProtocolDecl *ProtoType = Actions.ActOnStartProtocolInterface(
       AtLoc, protocolName, nameLoc, ProtocolRefs.data(), ProtocolRefs.size(),
       ProtocolLocs.data(), EndProtoLoc, attrs, &SkipBody);

clang/lib/Parse/Parser.cpp

@@ -1441,7 +1441,7 @@ Decl *Parser::ParseFunctionDefinition(ParsingDeclarator &D,
 
   // Tell the actions module that we have entered a function definition with the
   // specified Declarator for the function.
-  Sema::SkipBodyInfo SkipBody;
+  SkipBodyInfo SkipBody;
   Decl *Res = Actions.ActOnStartOfFunctionDef(getCurScope(), D,
                                               TemplateInfo.TemplateParams
                                                   ? *TemplateInfo.TemplateParams

clang/lib/Sema/SemaDecl.cpp

@@ -3037,7 +3037,7 @@ static void checkNewAttributesAfterDef(Sema &S, Decl *New, const Decl *Old) {
 
     if (isa<AliasAttr>(NewAttribute) || isa<IFuncAttr>(NewAttribute)) {
       if (FunctionDecl *FD = dyn_cast<FunctionDecl>(New)) {
-        Sema::SkipBodyInfo SkipBody;
+        SkipBodyInfo SkipBody;
         S.CheckForFunctionRedefinition(FD, cast<FunctionDecl>(Def), &SkipBody);
 
         // If we're skipping this definition, drop the "alias" attribute.
@@ -19999,7 +19999,7 @@ EnumConstantDecl *Sema::CheckEnumConstant(EnumDecl *Enum,
                                   Val, EnumVal);
 }
 
-Sema::SkipBodyInfo Sema::shouldSkipAnonEnumBody(Scope *S, IdentifierInfo *II,
+SkipBodyInfo Sema::shouldSkipAnonEnumBody(Scope *S, IdentifierInfo *II,
                                                 SourceLocation IILoc) {
   if (!(getLangOpts().Modules || getLangOpts().ModulesLocalVisibility) ||
       !getLangOpts().CPlusPlus)