[Parser] Better error-recovery to preserve operator decl's structures.

Author: nkcsgexi

lib/Parse/ParseDecl.cpp

@@ -5525,25 +5525,37 @@ Parser::parseDeclInfixOperator(SourceLoc OperatorLoc, Identifier Name,
   SourceLoc AssociativityLoc, AssociativityValueLoc,
     PrecedenceLoc, PrecedenceValueLoc,
     AssignmentLoc;
-  
+
+  auto ErrReturnFunc = [&] () {
+    skipUntilDeclRBrace();
+    assert(Tok.getKind() == tok::r_brace);
+    SourceLoc RBraceLoc = Tok.getLoc();
+    auto Res = new (Context)
+    InfixOperatorDecl(CurDeclContext, OperatorLoc, Name, NameLoc, LBraceLoc,
+                      AssociativityLoc.isInvalid(), AssociativityLoc,
+                      AssociativityValueLoc, PrecedenceLoc.isInvalid(),
+                      PrecedenceLoc, PrecedenceValueLoc,
+                      AssignmentLoc.isInvalid(), AssignmentLoc,
+                      RBraceLoc,
+                      InfixData(precedence, associativity, assignment));
+    Res->getAttrs() = Attributes;
+    return makeParserErrorResult(Res);
+  };
   while (!Tok.is(tok::r_brace)) {
     if (!Tok.is(tok::identifier)) {
       diagnose(Tok, diag::expected_operator_attribute);
-      skipUntilDeclRBrace();
-      return nullptr;
+      return ErrReturnFunc();
     }
 
     if (Tok.getText().equals("associativity")) {
       if (AssociativityLoc.isValid()) {
         diagnose(Tok, diag::operator_associativity_redeclared);
-        skipUntilDeclRBrace();
-        return nullptr;
+        return ErrReturnFunc();
       }
       AssociativityLoc = consumeToken();
       if (!Tok.is(tok::identifier)) {
         diagnose(Tok, diag::expected_infix_operator_associativity);
-        skipUntilDeclRBrace();
-        return nullptr;
+        return ErrReturnFunc();
       }
       auto parsedAssociativity
         = llvm::StringSwitch<Optional<Associativity>>(Tok.getText())
@@ -5553,8 +5565,7 @@ Parser::parseDeclInfixOperator(SourceLoc OperatorLoc, Identifier Name,
           .Default(None);
       if (!parsedAssociativity) {
         diagnose(Tok, diag::unknown_infix_operator_associativity, Tok.getText());
-        skipUntilDeclRBrace();
-        return nullptr;
+        return ErrReturnFunc();
       }
       associativity = *parsedAssociativity;
 
@@ -5565,14 +5576,12 @@ Parser::parseDeclInfixOperator(SourceLoc OperatorLoc, Identifier Name,
     if (Tok.getText().equals("precedence")) {
       if (PrecedenceLoc.isValid()) {
         diagnose(Tok, diag::operator_precedence_redeclared);
-        skipUntilDeclRBrace();
-        return nullptr;
+        return ErrReturnFunc();
       }
       PrecedenceLoc = consumeToken();
       if (!Tok.is(tok::integer_literal)) {
         diagnose(Tok, diag::expected_infix_operator_precedence);
-        skipUntilDeclRBrace();
-        return nullptr;
+        return ErrReturnFunc();
       }
       if (Tok.getText().getAsInteger(0, precedence)) {
         diagnose(Tok, diag::invalid_infix_operator_precedence);
@@ -5586,17 +5595,15 @@ Parser::parseDeclInfixOperator(SourceLoc OperatorLoc, Identifier Name,
     if (Tok.getText().equals("assignment")) {
       if (AssignmentLoc.isValid()) {
         diagnose(Tok, diag::operator_assignment_redeclared);
-        skipUntilDeclRBrace();
-        return nullptr;
+        return ErrReturnFunc();
       }
       AssignmentLoc = consumeToken();
       assignment = true;
       continue;
     }
 
     diagnose(Tok, diag::unknown_infix_operator_attribute, Tok.getText());
-    skipUntilDeclRBrace();
-    return nullptr;
+    return ErrReturnFunc();
   }
 
   SourceLoc RBraceLoc = Tok.getLoc();