SourceKit: Use Demangle::getTypeDeclForUSR() to implement 'CursorInfo for USR' request

Fixes <rdar://problem/47819208>.

Author: slavapestov

test/SourceKit/CursorInfo/cursor_usr.swift

@@ -2,8 +2,6 @@
 import Foo
 import FooSwiftModule
 
-var global: Int
-
 struct S1 {}
 
 func foo(x: FooStruct1) -> S1 {}
@@ -13,18 +11,18 @@ func foo(x: FooStruct1) -> S1 {}
 // RUN: %swiftc_driver -emit-module -o %t/FooSwiftModule.swiftmodule %S/Inputs/FooSwiftModule.swift
 
 // Sanity check that we have identical responses when things work.
-// RUN: %sourcekitd-test -req=cursor -pos=5:5 %s -- -I %t -F %S/../Inputs/libIDE-mock-sdk %mcp_opt %s > %t.from_offset.txt
-// RUN: %sourcekitd-test -req=cursor -usr "s:10cursor_usr6globalSivp" %s -- -I %t -F %S/../Inputs/libIDE-mock-sdk %mcp_opt %s > %t.from_usr.txt
+// RUN: %sourcekitd-test -req=cursor -pos=5:8 %s -- -I %t -F %S/../Inputs/libIDE-mock-sdk %mcp_opt %s > %t.from_offset.txt
+// RUN: %sourcekitd-test -req=cursor -usr "s:10cursor_usr2S1V" %s -- -I %t -F %S/../Inputs/libIDE-mock-sdk %mcp_opt %s > %t.from_usr.txt
 // RUN: %FileCheck %s -check-prefix=CHECK_SANITY1 < %t.from_offset.txt
 // RUN: %FileCheck %s -check-prefix=CHECK_SANITY1 < %t.from_usr.txt
 // RUN: diff -u %t.from_usr.txt %t.from_offset.txt
-// CHECK_SANITY1: source.lang.swift.decl.var.global (5:5-5:11)
-// CHECK_SANITY1-NEXT: global
-// CHECK_SANITY1-NEXT: s:10cursor_usr6globalSiv
-// CHECK_SANITY1-NEXT: Int
-// CHECK_SANITY1-NEXT: $sSiD
-// CHECK_SANITY1-NEXT: <Declaration>var global: <Type usr="s:Si">Int</Type></Declaration>
-// CHECK_SANITY1-NEXT: <decl.var.global><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>global</decl.name>: <decl.var.type><ref.struct usr="s:Si">Int</ref.struct></decl.var.type></decl.var.global>
+// CHECK_SANITY1: source.lang.swift.decl.struct (5:8-5:10)
+// CHECK_SANITY1-NEXT: S1
+// CHECK_SANITY1-NEXT: s:10cursor_usr2S1
+// CHECK_SANITY1-NEXT: S1.Type
+// CHECK_SANITY1-NEXT: $s10cursor_usr2S1VmD
+// CHECK_SANITY1-NEXT: <Declaration>struct S1</Declaration>
+// CHECK_SANITY1-NEXT: <decl.struct><syntaxtype.keyword>struct</syntaxtype.keyword> <decl.name>S1</decl.name></decl.struct>
 
 // Bogus USR.
 // RUN: %sourcekitd-test -req=cursor -usr "s:blahblahblah" %s -- -I %t -F %S/../Inputs/libIDE-mock-sdk %mcp_opt %s | %FileCheck %s -check-prefix=EMPTY
@@ -33,26 +31,8 @@ func foo(x: FooStruct1) -> S1 {}
 // FIXME: no support for clang USRs.
 // RUN: %sourcekitd-test -req=cursor -usr "c:@S@FooStruct1" %s -- -I %t -F %S/../Inputs/libIDE-mock-sdk %mcp_opt %s | %FileCheck %s -check-prefix=EMPTY
 // EMPTY: <empty cursor info>
-
-// FIXME: missing symbol shows up as some other part of the USR (the type here).
-// RUN: %sourcekitd-test -req=cursor -usr "s:10cursor_usr11global_noneSivp" %s -- -I %t -F %S/../Inputs/libIDE-mock-sdk %mcp_opt %s | %FileCheck %s -check-prefix=SHOULD_BE_EMPTY
-// SHOULD_BE_EMPTY: source.lang.swift.decl.struct ()
-// SHOULD_BE_EMPTY: Int
-
 // RUN: %sourcekitd-test -req=cursor -usr "s:10cursor_usr2S1V" %s -- -I %t -F %S/../Inputs/libIDE-mock-sdk %mcp_opt %s | %FileCheck %s -check-prefix=CHECK1
-// CHECK1: source.lang.swift.decl.struct (7:8-7:10)
+// CHECK1: source.lang.swift.decl.struct (5:8-5:10)
 // CHECK1: s1
 // CHECK1: <decl.struct><syntaxtype.keyword>struct</syntaxtype.keyword> <decl.name>S1</decl.name></decl.struct>
 
-// RUN: %sourcekitd-test -req=cursor -usr "s:14FooSwiftModule03fooB4FuncSiyF" %s -- -I %t -F %S/../Inputs/libIDE-mock-sdk %mcp_opt %s | %FileCheck %s -check-prefix=CHECK2
-// CHECK2: source.lang.swift.decl.function.free ()
-// CHECK2: fooSwiftFunc()
-// CHECK2: () -> Int
-// CHECK2: FooSwiftModule
-// CHECK2: <decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fooSwiftFunc</decl.name>() -&gt; <decl.function.returntype><ref.struct usr="s:Si">Int</ref.struct></decl.function.returntype></decl.function.free>
-
-// RUN: %sourcekitd-test -req=cursor -usr "s:10cursor_usr3fooyAA2S1VSC10FooStruct1VF" %s -- -I %t -F %S/../Inputs/libIDE-mock-sdk %mcp_opt %s | %FileCheck %s -check-prefix=CHECK3
-// CHECK3: source.lang.swift.decl.function.free (9:6-9:24)
-// CHECK3: foo(x:)
-// CHECK3: (FooStruct1) -> S1
-// CHECK3: <decl.function.free><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>foo</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>x</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.struct usr="c:@S@FooStruct1">FooStruct1</ref.struct></decl.var.parameter.type></decl.var.parameter>) -&gt; <decl.function.returntype><ref.struct usr="s:10cursor_usr2S1V">S1</ref.struct></decl.function.returntype></decl.function.free>

tools/SourceKit/lib/SwiftLang/SwiftSourceDocInfo.cpp

@@ -16,6 +16,7 @@
 #include "SourceKit/Support/ImmutableTextBuffer.h"
 #include "SourceKit/Support/Logging.h"
 
+#include "swift/AST/ASTDemangler.h"
 #include "swift/AST/ASTPrinter.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/NameLookup.h"
@@ -1724,8 +1725,7 @@ resolveCursorFromUSR(SwiftLangSupport &Lang, StringRef InputFile, StringRef USR,
       }
 
       auto &context = CompIns.getASTContext();
-      std::string error;
-      Decl *D = ide::getDeclFromUSR(context, USR, error);
+      TypeDecl *D = Demangle::getTypeDeclForUSR(context, USR);
 
       if (!D) {
         Receiver(CursorInfoData());
@@ -1738,15 +1738,15 @@ resolveCursorFromUSR(SwiftLangSupport &Lang, StringRef InputFile, StringRef USR,
       if (auto *M = dyn_cast<ModuleDecl>(D)) {
         passCursorInfoForModule(M, Lang.getIFaceGenContexts(), CompInvok,
                                 Receiver);
-      } else if (auto *VD = dyn_cast<ValueDecl>(D)) {
-        auto *DC = VD->getDeclContext();
+      } else {
+        auto *DC = D->getDeclContext();
         Type selfTy;
         if (DC->isTypeContext()) {
           selfTy = DC->getSelfInterfaceType();
-          selfTy = VD->getInnermostDeclContext()->mapTypeIntoContext(selfTy);
+          selfTy = D->getInnermostDeclContext()->mapTypeIntoContext(selfTy);
         }
         bool Failed =
-            passCursorInfoForDecl(/*SourceFile*/nullptr, VD, MainModule, selfTy,
+            passCursorInfoForDecl(/*SourceFile*/nullptr, D, MainModule, selfTy,
                                   /*IsRef=*/false, false, ResolvedCursorInfo(),
                                   BufferID, SourceLoc(), {}, Lang, CompInvok,
                                   PreviousASTSnaps, Receiver);