Merge pull request #28609 from eeckstein/fix-remangler

Demangler: support protocols as parents of bound generic types to avoid crash in the indexer for invalid swift code.

Author: eeckstein

lib/Demangling/Remangler.cpp

@@ -487,6 +487,12 @@ void Remangler::mangleAnyNominalType(Node *node) {
 void Remangler::mangleGenericArgs(Node *node, char &Separator,
                                   bool fullSubstitutionMap) {
   switch (node->getKind()) {
+    case Node::Kind::Protocol:
+      // A protocol cannot be the parent of a nominal type, so this case should
+      // never be hit by valid swift code. But the indexer might generate a URL
+      // from invalid swift code, which has a bound generic inside a protocol.
+      // The ASTMangler treats a protocol like any other nominal type in this
+      // case, so we also support it in the remangler.
     case Node::Kind::Structure:
     case Node::Kind::Enum:
     case Node::Kind::Class:

test/Demangle/Inputs/manglings.txt

@@ -328,6 +328,7 @@ _$S3BBBBf0602365061_ ---> _$S3BBBBf0602365061_
 _$S3BBBBi0602365061_ ---> _$S3BBBBi0602365061_
 _$S3BBBBv0602365061_ ---> _$S3BBBBv0602365061_
 _T0lxxxmmmTk ---> _T0lxxxmmmTk
+$s4Test5ProtoP8IteratorV10collectionAEy_qd__Gqd___tcfc ---> Test.Proto.Iterator.init(collection: A1) -> Test.Proto.Iterator<A1>
 $s4test3fooV4blahyAA1SV1fQryFQOy_Qo_AHF ---> test.foo.blah(<<opaque return type of test.S.f() -> some>>.0) -> <<opaque return type of test.S.f() -> some>>.0
 $S3nix8MystructV1xACyxGx_tcfc7MyaliasL_ayx__GD ---> Myalias #1 in nix.Mystruct<A>.init(x: A) -> nix.Mystruct<A>
 $S3nix7MyclassCfd7MyaliasL_ayx__GD ---> Myalias #1 in nix.Myclass<A>.deinit