SIL: Fix lowering of local functions with explicit isolated parameter

When the isolated parameter is the function's own parameter, it is
not a capture.

Fixes rdar://135607071.

Author: slavapestov

lib/Sema/TypeCheckCaptures.cpp

@@ -762,7 +762,10 @@ CaptureInfo CaptureInfoRequest::evaluate(Evaluator &evaluator,
     if (actorIsolation.getKind() == ActorIsolation::ActorInstance) {
       if (auto *var = actorIsolation.getActorInstance()) {
         assert(isa<ParamDecl>(var));
-        finder.addCapture(CapturedValue(var, 0, AFD->getLoc()));
+        // Don't capture anything if the isolation parameter is a parameter
+        // of the local function.
+        if (var->getDeclContext() != AFD)
+          finder.addCapture(CapturedValue(var, 0, AFD->getLoc()));
       }
     }
   }

test/SILGen/local_function_isolation.swift

@@ -87,4 +87,15 @@ actor NestedAsyncInSyncActor {
     }
     _ = middle
   }
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s24local_function_isolation13outerFunctionyyScA_pYaF : $@convention(thin) @async (@guaranteed any Actor) -> () {
+func outerFunction(_ a: any Actor) async {
+  // CHECK-LABEL: sil private [ossa] @$s24local_function_isolation13outerFunctionyyScA_pYaF06middleE0L_yyScA_pYaF : $@convention(thin) @async (@guaranteed any Actor) -> () {
+  func middleFunction(_ isolated: any Actor) async {
+    // CHECK-LABEL: sil private [ossa] @$s24local_function_isolation13outerFunctionyyScA_pYaF06middleE0L_yyScA_pYaF05innerE0L_yyYaF : $@convention(thin) @async () -> () {
+    func innerFunction() async {}
+  }
+
+  await middleFunction(a)
 }