[IDE] Skip synthesized curry thunks and walk their unwrapped expression

SemaAnnotator was walking into an autoclosure and then manually running
`passReference` on the unwrapped expression without walking it. Since
its synthesized anyway, skip walking the autoclosure entirely and walk
the unwrapped expression instead.

Fix `swift::ide::isBeingCalled` to look through `IdentityExpr`s and
`swift::ide::getBase` also not unwrapping curry thunks.

Resolves rdar://81312849

Author: bnbarham

include/swift/IDE/Utils.h

@@ -588,8 +588,10 @@ ClangNode extensionGetClangNode(const ExtensionDecl *ext);
 
 /// Utility for finding the referenced declaration from a call, which might
 /// include a second level of function application for a 'self.' expression,
-/// or a curry thunk, etc.
-std::pair<Type, ConcreteDeclRef> getReferencedDecl(Expr *expr);
+/// or a curry thunk, etc. If \p semantic is true then the underlying semantic
+/// expression of \p expr is used.
+std::pair<Type, ConcreteDeclRef> getReferencedDecl(Expr *expr,
+                                                   bool semantic = true);
 
 /// Whether the last expression in \p ExprStack is being called.
 bool isBeingCalled(ArrayRef<Expr*> ExprStack);

lib/IDE/SourceEntityWalker.cpp

@@ -275,6 +275,21 @@ std::pair<bool, Expr *> SemaAnnotator::walkToExprPre(Expr *E) {
     return { false, E };
   }
 
+  auto doStopTraversal = [&]() -> std::pair<bool, Expr *> {
+    Cancelled = true;
+    return { false, nullptr };
+  };
+
+  // Skip the synthesized curry thunks and just walk over the unwrapped
+  // expression
+  if (auto *ACE = dyn_cast<AutoClosureExpr>(E)) {
+    if (auto *SubExpr = ACE->getUnwrappedCurryThunkExpr()) {
+      if (!SubExpr->walk(*this))
+        return doStopTraversal();
+      return { false, E };
+    }
+  }
+
   if (!SEWalker.walkToExprPre(E)) {
     return { false, E };
   }
@@ -291,30 +306,9 @@ std::pair<bool, Expr *> SemaAnnotator::walkToExprPre(Expr *E) {
     return { false, E };
   };
 
-  auto doStopTraversal = [&]() -> std::pair<bool, Expr *> {
-    Cancelled = true;
-    return { false, nullptr };
-  };
-
   if (auto *CtorRefE = dyn_cast<ConstructorRefCallExpr>(E))
     CtorRefs.push_back(CtorRefE);
 
-  if (auto *ACE = dyn_cast<AutoClosureExpr>(E)) {
-    if (auto *SubExpr = ACE->getUnwrappedCurryThunkExpr()) {
-      if (auto *DRE = dyn_cast<DeclRefExpr>(SubExpr)) {
-        if (!passReference(DRE->getDecl(), DRE->getType(),
-                           DRE->getNameLoc(),
-                           ReferenceMetaData(getReferenceKind(Parent.getAsExpr(), DRE),
-                                             OpAccess)))
-          return doStopTraversal();
-
-        return doSkipChildren();
-      }
-    }
-
-    return { true, E };
-  }
-
   if (auto *DRE = dyn_cast<DeclRefExpr>(E)) {
     auto *FD = dyn_cast<FuncDecl>(DRE->getDecl());
     // Handle implicit callAsFunction reference. An explicit reference will be

lib/IDE/Utils.cpp

@@ -1153,7 +1153,11 @@ ClangNode swift::ide::extensionGetClangNode(const ExtensionDecl *ext) {
   return ClangNode();
 }
 
-std::pair<Type, ConcreteDeclRef> swift::ide::getReferencedDecl(Expr *expr) {
+std::pair<Type, ConcreteDeclRef> swift::ide::getReferencedDecl(Expr *expr,
+                                                               bool semantic) {
+  if (semantic)
+    expr = expr->getSemanticsProvidingExpr();
+
   auto exprTy = expr->getType();
 
   // Look through unbound instance member accesses.
@@ -1219,13 +1223,19 @@ Expr *swift::ide::getBase(ArrayRef<Expr *> ExprStack) {
   Expr *CurrentE = ExprStack.back();
   Expr *ParentE = getContainingExpr(ExprStack, 1);
   Expr *Base = nullptr;
+
   if (auto DSE = dyn_cast_or_null<DotSyntaxCallExpr>(ParentE))
     Base = DSE->getBase();
   else if (auto MRE = dyn_cast<MemberRefExpr>(CurrentE))
     Base = MRE->getBase();
   else if (auto SE = dyn_cast<SubscriptExpr>(CurrentE))
     Base = SE->getBase();
 
+  // Look through curry thunks
+  if (auto ACE = dyn_cast_or_null<AutoClosureExpr>(Base))
+    if (auto *Unwrapped = ACE->getUnwrappedCurryThunkExpr())
+      Base = Unwrapped;
+
   if (Base) {
     while (auto ICE = dyn_cast<ImplicitConversionExpr>(Base))
       Base = ICE->getSubExpr();

lib/Migrator/APIDiffMigratorPass.cpp

@@ -572,7 +572,7 @@ struct APIDiffMigratorPass : public ASTMigratorPass, public SourceEntityWalker {
       }
       return false;
     };
-    if (auto *VD = getReferencedDecl(Call).second.getDecl())
+    if (auto *VD = getReferencedDecl(Call, /*semantic=*/false).second.getDecl())
       if (handleDecl(VD, Call->getSourceRange()))
         return true;
 

test/Index/index_curry_thunk.swift

@@ -0,0 +1,12 @@
+// RUN: %target-swift-ide-test -print-indexed-symbols -source-filename %s | %FileCheck %s
+
+struct SomeStruct {
+  func simple(_ someClosure: () -> Void) { }
+}
+
+func test(s: SomeStruct) {
+  s.simple { }
+  // CHECK: [[@LINE-1]]:5 | instance-method/Swift | simple(_:) | s:14swift_ide_test10SomeStructV6simpleyyyyXEF | Ref,Call,RelRec,RelCall,RelCont | rel: 2
+  (((s).simple)) { }
+  // CHECK: [[@LINE-1]]:9 | instance-method/Swift | simple(_:) | s:14swift_ide_test10SomeStructV6simpleyyyyXEF | Ref,Call,RelRec,RelCall,RelCont | rel: 2
+}