[IDE] Don't produce USRs for nameless parameters.

...and /do/ produce them for 'self' parameters in destructors when
they /are/ named. I suspect this was the cause of the original
problem.

Author: jrose-apple

include/swift/AST/ASTMangler.h

@@ -122,7 +122,7 @@ class ASTMangler : public Mangler {
 
   std::string mangleTypeAsContextUSR(const NominalTypeDecl *type);
 
-  std::string mangleDeclAsUSR(ValueDecl *Decl, StringRef USRPrefix);
+  std::string mangleDeclAsUSR(const ValueDecl *Decl, StringRef USRPrefix);
 
   std::string mangleAccessorEntityAsUSR(AccessorKind kind,
                                         AddressorKind addressorKind,

lib/AST/USRGeneration.cpp

@@ -141,7 +141,7 @@ static bool ShouldUseObjCUSR(const Decl *D) {
 }
 
 bool ide::printDeclUSR(const ValueDecl *D, raw_ostream &OS) {
-  if (!D->hasName() && !isa<ParamDecl>(D) &&
+  if (!D->hasName() &&
       (!isa<FuncDecl>(D) ||
        cast<FuncDecl>(D)->getAccessorKind() == AccessorKind::NotAccessor))
     return true; // Ignore.
@@ -150,8 +150,6 @@ bool ide::printDeclUSR(const ValueDecl *D, raw_ostream &OS) {
   if (isa<ModuleDecl>(D))
     return true; // Ignore.
 
-  ValueDecl *VD = const_cast<ValueDecl *>(D);
-
   auto interpretAsClangNode = [](const ValueDecl *D)->ClangNode {
     ClangNode ClangN = D->getClangNode();
     if (auto ClangD = ClangN.getAsDecl()) {
@@ -204,8 +202,8 @@ bool ide::printDeclUSR(const ValueDecl *D, raw_ostream &OS) {
     return Ignore;
   }
 
-  if (ShouldUseObjCUSR(VD)) {
-    return printObjCUSR(VD, OS);
+  if (ShouldUseObjCUSR(D)) {
+    return printObjCUSR(D, OS);
   }
 
   if (!D->hasInterfaceType())
@@ -217,12 +215,8 @@ bool ide::printDeclUSR(const ValueDecl *D, raw_ostream &OS) {
       }))
     return true;
 
-  // FIXME: mangling 'self' in destructors crashes in mangler.
-  if (isa<ParamDecl>(VD) && isa<DestructorDecl>(VD->getDeclContext()))
-    return true;
-
   Mangle::ASTMangler NewMangler;
-  std::string Mangled = NewMangler.mangleDeclAsUSR(VD, getUSRSpacePrefix());
+  std::string Mangled = NewMangler.mangleDeclAsUSR(D, getUSRSpacePrefix());
 
   OS << Mangled;
 

test/IDE/print_usrs.swift

@@ -64,7 +64,7 @@ class GenericClass {
   // CHECK: [[@LINE+1]]:3 s:14swift_ide_test12GenericClassCfd{{$}}
   deinit {
     // CHECK: [[@LINE+2]]:18 s:14swift_ide_test12GenericClassC9classFuncyACFZ{{$}}
-    // CHECK: [[@LINE+1]]:28 ERROR:no-usr{{$}}
+    // CHECK: [[@LINE+1]]:28 s:14swift_ide_test12GenericClassCfd4selfL_ACv{{$}}
     GenericClass.classFunc(self)
   }
 

test/Index/kinds.swift

@@ -51,8 +51,8 @@ class AClass {
   // CHECK-NEXT: RelChild | instance-method/Swift | instanceMethod(a:b:_:d:_:) | s:14swift_ide_test6AClassC14instanceMethodySi1a_Si1bS2i1dSitF
   // CHECK: [[@LINE-5]]:33 | param(local)/Swift | b | s:{{.*}} | Def,RelChild | rel: 1
   // CHECK: [[@LINE-6]]:43 | param(local)/Swift | c | s:{{.*}} | Def,RelChild | rel: 1
-  // CHECK: [[@LINE-7]]:53 | param(local)/Swift | _ | s:{{.*}} | Def,RelChild | rel: 1
-  // CHECK: [[@LINE-8]]:61 | param/Swift | _ | s:{{.*}} | Def,RelChild | rel: 1
+  // CHECK-NOT: {{^}}[[@LINE-7]]:53 |
+  // CHECK-NOT: {{^}}[[@LINE-8]]:61 |
 
     _ = a
     // CHECK: [[@LINE-1]]:9 | param/Swift | a | s:{{.*}} | Ref,Read,RelCont | rel: 1