Simplify parsing and fix astgen failures

Author: Azoy

lib/AST/ASTPrinter.cpp

@@ -8388,7 +8388,28 @@ void GenericParamList::print(ASTPrinter &Printer,
   interleave(
       *this,
       [&](const GenericTypeParamDecl *P) {
-        P->print(Printer, PO);
+        Printer << P->getName();
+        if (!P->getInherited().empty()) {
+          Printer << " : ";
+
+          auto loc = P->getInherited().getEntry(0);
+          if (willUseTypeReprPrinting(loc, nullptr, PO)) {
+            loc.getTypeRepr()->print(Printer, PO);
+          } else {
+            loc.getType()->print(Printer, PO);
+          }
+
+          if (P->hasDefaultType()) {
+            Printer << " = ";
+
+            auto loc = P->getDefaultTypeRepr();
+            if (loc && willUseTypeReprPrinting(loc, nullptr, PO)) {
+              loc->print(Printer, PO);
+            } else {
+              P->getDefaultType()->print(Printer, PO);
+            }
+          }
+        }
       },
       [&] { Printer << ", "; });
 

lib/Parse/ParseGeneric.cpp

@@ -130,37 +130,6 @@ Parser::parseGenericParametersBeforeWhere(SourceLoc LAngleLoc,
         Inherited.push_back({Ty.get()});
     }
 
-    // Parse the '=' followed by a type.
-    TypeLoc DefaultType;
-
-    if (Context.LangOpts.hasFeature(Feature::DefaultGenerics)) {
-      // TODO: Don't allow defaults for values or parameter packs at the moment.
-      if (Tok.is(tok::equal) && !EachLoc.isValid() && !LetLoc.isValid()) {
-        (void)consumeToken();
-        ParserResult<TypeRepr> Ty;
-
-        if (Tok.isAny(tok::identifier, tok::code_complete, tok::kw_protocol,
-                      tok::kw_Any) || Tok.isTilde()) {
-          Ty = parseType();
-        } else if (Tok.is(tok::kw_class)) {
-          diagnose(Tok, diag::unexpected_class_constraint);
-          diagnose(Tok, diag::suggest_anyobject)
-          .fixItReplace(Tok.getLoc(), "AnyObject");
-          consumeToken();
-          Result.setIsParseError();
-        } else {
-          diagnose(Tok, diag::expected_generics_type_restriction, Name);
-          Result.setIsParseError();
-        }
-
-        if (Ty.hasCodeCompletion())
-          return makeParserCodeCompletionStatus();
-
-        if (Ty.isNonNull())
-          DefaultType = Ty.get();
-      }
-    }
-
     auto ParamKind = GenericTypeParamKind::Type;
     SourceLoc SpecifierLoc;
 
@@ -172,8 +141,22 @@ Parser::parseGenericParametersBeforeWhere(SourceLoc LAngleLoc,
       SpecifierLoc = LetLoc;
     }
 
+    // Parse the '=' followed by a type.
+    ParserResult<TypeRepr> DefaultType;
+
+    if (Context.LangOpts.hasFeature(Feature::DefaultGenerics)) {
+      // TODO: Don't allow defaults for values or parameter packs at the moment.
+      if (Tok.is(tok::equal) && ParamKind == GenericTypeParamKind::Type) {
+        consumeToken(tok::equal);
+        DefaultType = parseType(diag::expected_type);
+        Result |= DefaultType;
+        if (DefaultType.isNull())
+          return Result;
+      }
+    }
+
     auto *Param = GenericTypeParamDecl::createParsed(
-        CurDeclContext, Name, NameLoc, SpecifierLoc, DefaultType,
+        CurDeclContext, Name, NameLoc, SpecifierLoc, DefaultType.getPtrOrNull(),
         /*index*/ GenericParams.size(), ParamKind);
     if (!Inherited.empty())
       Param->setInherited(Context.AllocateCopy(Inherited));

test/ASTGen/decls.swift

@@ -13,7 +13,7 @@
 
 // RUN: %diff -u %t/astgen.ast %t/cpp-parser.ast
 
-// RUN: %target-run-simple-swift(-Xfrontend -disable-availability-checking -Xfrontend -enable-experimental-concurrency -enable-experimental-feature CoroutineAccessors -enable-experimental-feature DefaultIsolationPerFile -enable-experimental-feature ParserASTGen)
+// RUN: %target-run-simple-swift(-Xfrontend -disable-availability-checking -Xfrontend -enable-experimental-concurrency -enable-experimental-feature CoroutineAccessors -enable-experimental-feature DefaultIsolationPerFile -enable-experimental-feature DefaultGenerics -enable-experimental-feature ParserASTGen)
 
 // REQUIRES: executable_test
 // REQUIRES: swift_swift_parser
@@ -370,4 +370,3 @@ struct Vec<Element, A = SystemAllocator> {}
 enum DefaultGenericEnum<T = Int> {}
 class DefaultGenericClass<T, U: Proto1, V: Proto2 = SystemAllocator> {}
 typealias DefaultGenericTypealias<T = Int> = Vec<T>
-func defaultGenericFunc<T = String>() {}