[AST] Separate out the operations that set *parsed* bodies of functions.

When the parser wires up the body of a function, it's a legitimate use of
setting a parsed body. Separate these out from the other uses of
setBody() that we want to eliminate over time.

Author: DougGregor

include/swift/AST/Decl.h

@@ -5773,6 +5773,11 @@ class AbstractFunctionDecl : public GenericContext, public ValueDecl {
     setBodyKind(BodyKind::Unparsed);
   }
 
+  /// Provide the parsed body for the function.
+  void setBodyParsed(BraceStmt *S) {
+    setBody(S, BodyKind::Parsed);
+  }
+
   /// Note that parsing for the body was delayed.
   ///
   /// The function should return the body statement and a flag indicating

lib/Parse/ParseDecl.cpp

@@ -4636,9 +4636,9 @@ ParserStatus Parser::parseGetSet(ParseDeclOptions Flags,
                 Indices, ElementTy, StaticLoc, Flags, AccessorKind::Get,
                 storage, this, /*AccessorKeywordLoc*/ SourceLoc());
             CCE = new (Context) CodeCompletionExpr(Tok.getLoc());
-            getter->setBody(BraceStmt::create(Context, Tok.getLoc(),
-                                              ASTNode(CCE), Tok.getLoc(),
-                                              /*implicit*/ true));
+            getter->setBodyParsed(BraceStmt::create(Context, Tok.getLoc(),
+                                                    ASTNode(CCE), Tok.getLoc(),
+                                                    /*implicit*/ true));
             accessors.add(getter);
             CodeCompletion->setParsedDecl(getter);
           } else {
@@ -5763,7 +5763,7 @@ void Parser::parseAbstractFunctionBody(AbstractFunctionDecl *AFD) {
   ParserResult<BraceStmt> Body = parseBraceItemList(diag::invalid_diagnostic);
   if (!Body.isNull()) {
     BraceStmt * BS = Body.get();
-    AFD->setBody(BS);
+    AFD->setBodyParsed(BS);
 
     // If the body consists of a single expression, turn it into a return
     // statement.
@@ -5853,7 +5853,7 @@ bool Parser::parseAbstractFunctionBodyDelayed(AbstractFunctionDecl *AFD) {
     // FIXME: Should do some sort of error recovery here?
     return true;
   } else {
-    AFD->setBody(Body.get());
+    AFD->setBodyParsed(Body.get());
   }
 
   return false;

lib/Parse/ParseStmt.cpp

@@ -988,7 +988,7 @@ ParserResult<Stmt> Parser::parseStmtDefer() {
     if (Body.isNull())
       return nullptr;
     Status |= Body;
-    tempDecl->setBody(Body.get());
+    tempDecl->setBodyParsed(Body.get());
   }
 
   SourceLoc loc = tempDecl->getBodySourceRange().Start;