SILFunctionType: Loosened assert.

Allowed SILFunctionType instances for pseudogeneric coroutines without
signatures to be created.  Such instances are created by
SILTypeSubstituter::substSILFunctionType when SILGen'ing a conformance
of a pseudogeneric type to a protocol featuring a coroutine requirement.

rdar://81421394

Author: nate-chandler

lib/AST/ASTContext.cpp

@@ -4594,8 +4594,9 @@ CanSILFunctionType SILFunctionType::get(
     ProtocolConformanceRef witnessMethodConformance) {
   assert(coroutineKind == SILCoroutineKind::None || normalResults.empty());
   assert(coroutineKind != SILCoroutineKind::None || yields.empty());
-  assert(!ext.isPseudogeneric() || genericSig);
-  
+  assert(!ext.isPseudogeneric() || genericSig ||
+         coroutineKind != SILCoroutineKind::None);
+
   patternSubs = patternSubs.getCanonical();
   invocationSubs = invocationSubs.getCanonical();
 

validation-test/SILGen/Inputs/rdar81421394.h

@@ -0,0 +1,10 @@
+#include <Foundation/Foundation.h>
+
+#pragma clang assume_nonnull begin
+
+@interface Ranger<__covariant SectionType, __covariant ItemType> : NSObject {
+  NSRange _range;
+}
+@property(nonatomic) NSRange range;
+@end
+#pragma clang assume_nonnull end

validation-test/SILGen/Inputs/rdar81421394.m

@@ -0,0 +1,22 @@
+#include "rdar81421394.h"
+
+#pragma clang assume_nonnull begin
+@implementation Ranger
+- (instancetype)init {
+  if (self = [super init]) {
+    NSLog(@"calling init");
+    self->_range = NSMakeRange(0, 0);
+  }
+  return self;
+}
+- (void)setRange:(NSRange)newRange {
+  NSLog(@"%s: %@->%@", __PRETTY_FUNCTION__, NSStringFromRange(_range),
+        NSStringFromRange(newRange));
+  _range = newRange;
+}
+- (NSRange)range {
+  NSLog(@"%s: %@", __PRETTY_FUNCTION__, NSStringFromRange(_range));
+  return _range;
+}
+@end
+#pragma clang assume_nonnull end

validation-test/SILGen/rdar81421394.swift

@@ -0,0 +1,43 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-clang %S/Inputs/rdar81421394.m -I %S/Inputs -c -o %t/rdar81421394.o
+// RUN: %target-build-swift -Xfrontend -disable-availability-checking -import-objc-header %S/Inputs/rdar81421394.h -Xlinker %t/rdar81421394.o %s -o %t/main
+// RUN: %target-codesign %t/main
+// RUN: %target-run %t/main | %FileCheck %s
+
+// REQUIRES: executable_test
+// REQUIRES: objc_interop
+
+// UNSUPPORTED: use_os_stdlib
+// UNSUPPORTED: back_deployment_runtime
+
+protocol RangeFinder {
+    var range: NSRange { get set }
+}
+
+extension Ranger : RangeFinder {}
+
+class Wrapper {
+  let instance: Ranger<AnyObject, NSObject>
+
+  init() {
+    instance = Ranger()
+  }
+
+  var range: NSRange {
+    _read {
+      yield instance.range
+    }
+    _modify {
+      print("staring modify")
+      yield &instance.range
+      print("ending modify")
+    }
+  }
+}
+
+let w = Wrapper()
+print("begin:", w.range)
+// CHECK: begin: {0, 0}
+w.range = NSRange(location: 3, length: 5)
+// CHECK: end: {3, 5}
+print("end:", w.range)