swift-api-digester: diagnose generic signature change for any declarations.

Author: nkcsgexi

include/swift/IDE/DigesterEnums.def

@@ -62,6 +62,7 @@ NODE_ANNOTATION(OwnershipChange)
 NODE_ANNOTATION(ChangeObjC)
 NODE_ANNOTATION(ChangeFixedLayout)
 NODE_ANNOTATION(ChangeFrozen)
+NODE_ANNOTATION(ChangeGenericSignature)
 NODE_ANNOTATION(RawTypeLeft)
 NODE_ANNOTATION(RawTypeRight)
 

test/api-digester/Inputs/cake1.swift

@@ -36,3 +36,11 @@ public struct C6 {}
 
 @_frozen
 public enum IceKind {}
+
+public protocol P1 {}
+
+public protocol P2 {}
+
+public extension P1 where Self: P2 {
+  func P1Constraint() {}
+}

test/api-digester/Inputs/cake2.swift

@@ -35,4 +35,12 @@ public class C5 {}
 @_fixed_layout
 public struct C6 {}
 
-public enum IceKind {}
+public enum IceKind {}
+
+public protocol P1 {}
+
+public protocol P2 {}
+
+public extension P1 {
+  func P1Constraint() {}
+}

test/api-digester/Outputs/Cake-abi.txt

@@ -1,4 +1,7 @@
 
+/* Generic Signature Changes */
+cake1: Func P1.P1Constraint() has generic signature change from <τ_0_0 where τ_0_0 : P1, τ_0_0 : P2> to <τ_0_0 where τ_0_0 : P1>
+
 /* RawRepresentable Changes */
 
 /* Removed Decls */

test/api-digester/Outputs/Cake.txt

@@ -1,4 +1,7 @@
 
+/* Generic Signature Changes */
+cake1: Func P1.P1Constraint() has generic signature change from <Self where Self : P1, Self : P2> to <Self where Self : P1>
+
 /* RawRepresentable Changes */
 
 /* Removed Decls */

test/api-digester/Outputs/apinotes-diags-3-4.txt

@@ -1,4 +1,6 @@
 
+/* Generic Signature Changes */
+
 /* RawRepresentable Changes */
 APINotesTest(APINotesTest.h): TypeAlias AnimalAttributeName(NSString) is now String representable
 

test/api-digester/Outputs/apinotes-diags.txt

@@ -1,4 +1,8 @@
 
+/* Generic Signature Changes */
+APINotesTest(APINotesTest.h): Func SwiftTypeWithMethodLeft.minusPrint() has generic signature change from <Self where Self : SwiftTypeWithMethodLeft> to <Self where Self : SwiftTypeWithMethodRight>
+APINotesTest(APINotesTest.h): Func SwiftTypeWithMethodLeft.plusPrint() has generic signature change from <Self where Self : SwiftTypeWithMethodLeft> to <Self where Self : SwiftTypeWithMethodRight>
+
 /* RawRepresentable Changes */
 APINotesTest(APINotesTest.h): TypeAlias CatAttributeName(NSString) is now String representable
 

tools/swift-api-digester/swift-api-digester.cpp

@@ -2505,6 +2505,9 @@ static void detectDeclChange(NodePtr L, NodePtr R) {
       if (LD->hasDeclAttribute(Info.Kind) != RD->hasDeclAttribute(Info.Kind))
         L->annotate(Info.Annotation);
     }
+    // Mark generic signature change
+    if (LD->getGenericSignature() != RD->getGenericSignature())
+      L->annotate(NodeAnnotation::ChangeGenericSignature);
     detectRename(L, R);
   }
 }
@@ -3441,13 +3444,35 @@ class DiagnosisEmitter : public SDKNodeVisitor {
     static void theme(raw_ostream &OS) { OS << "RawRepresentable Changes"; };
   };
 
+  struct GenericSignatureChangeDiag: public DiagBase {
+    DeclKind Kind;
+    StringRef DeclName;
+    StringRef GSBefore;
+    StringRef GSAfter;
+    GenericSignatureChangeDiag(MetaInfo Info, DeclKind Kind, StringRef DeclName,
+      StringRef GSBefore, StringRef GSAfter): DiagBase(Info), Kind(Kind),
+      DeclName(DeclName), GSBefore(GSBefore), GSAfter(GSAfter) {}
+    bool operator<(GenericSignatureChangeDiag Other) const {
+      if (Kind != Other.Kind)
+        return Kind < Other.Kind;
+      return DeclName.compare(Other.DeclName) < 0;
+    }
+    void output() const override {
+      llvm::outs() << Kind << " " << printName(DeclName)
+        << " has generic signature change from " << GSBefore << " to "
+        << GSAfter << "\n";
+    }
+    static void theme(raw_ostream &OS) { OS << "Generic Signature Changes"; };
+  };
+
   std::set<SDKNodeDecl*> AddedDecls;
   DiagBag<DeclAttrDiag> AttrChangedDecls;
   DiagBag<DeclTypeChangeDiag> TypeChangedDecls;
   DiagBag<RenamedDeclDiag> RenamedDecls;
   DiagBag<MovedDeclDiag> MovedDecls;
   DiagBag<RemovedDeclDiag> RemovedDecls;
   DiagBag<RawRepresentableChangeDiag> RawRepresentableDecls;
+  DiagBag<GenericSignatureChangeDiag> GSChangeDecls;
 
   UpdatedNodesMap &UpdateMap;
   NodeMap &TypeAliasUpdateMap;
@@ -3697,6 +3722,15 @@ void DiagnosisEmitter::handle(const SDKNodeDecl *Node, NodeAnnotation Anno) {
         getOwnershipDescription(Count->getReferenceOwnership()));
     return;
   }
+  case NodeAnnotation::ChangeGenericSignature: {
+    MetaInfo ScreenInfo(Node, false);
+    GSChangeDecls.Diags.emplace_back(ScreenInfo, Node->getDeclKind(),
+      Node->getFullyQualifiedName(), Node->getGenericSignature(),
+      UpdateMap.findUpdateCounterpart(Node)->getAs<SDKNodeDecl>()->
+                                     getGenericSignature());
+    return;
+  }
+
   default: {
     // Diagnose the addition/removal of attributes with ABI impact.
     auto Infos = Ctx.getABIAttributeInfo();