Merge pull request #25481 from jckarter/dynamic-self-reabstraction-context-5.1

[5.1] SILGen: Map dynamic self out of context when mangling reabstraction thunk symbols.

Author: jckarter

lib/SILGen/SILGenThunk.cpp

@@ -312,10 +312,15 @@ getOrCreateReabstractionThunk(CanSILFunctionType thunkType,
     ->getCanonicalType();
   auto toInterfaceType = toType->mapTypeOutOfContext()
     ->getCanonicalType();
+  CanType dynamicSelfInterfaceType;
+  if (dynamicSelfType)
+    dynamicSelfInterfaceType = dynamicSelfType->mapTypeOutOfContext()
+      ->getCanonicalType();
 
   Mangle::ASTMangler NewMangler;
   std::string name = NewMangler.mangleReabstractionThunkHelper(thunkType,
-                       fromInterfaceType, toInterfaceType, dynamicSelfType,
+                       fromInterfaceType, toInterfaceType,
+                       dynamicSelfInterfaceType,
                        M.getSwiftModule());
 
   auto loc = RegularLocation::getAutoGeneratedLocation();

test/SILGen/dynamic_self_reabstraction.swift

@@ -0,0 +1,9 @@
+// RUN: %target-swift-emit-silgen %s -verify
+
+func foo<T>(_ f: () -> T) -> T { return f() }
+
+class Foo<U> {
+  func bar() -> Self {
+    return foo { self }
+  }
+}