[CodeCompletion] Fix a crash in callee analysis

struct Wrap<T> {
  func method<U>(_ fn: (T) -> U) -> Wrap<U> {}
}
func testGenricMethodOnGenericOfArchetype<Val>(value: Wrap<Val>) {
  value.method(#^HERE^#)
}

In this case, the type of value is `Wrap<Val[archetype]>`.
`Type::getTypeOfMember()` for 'method' method returns
`( (Val[archetype]) -> U[generic param]) -> Wrap<U[generic param]>`
which crashs 'mapTypeIntoContext()' because it already hass archetype.

rdar://problem/52386176

Author: rintaro

lib/IDE/ExprContextAnalysis.cpp

@@ -307,9 +307,10 @@ static void collectPossibleCalleesByQualifiedLookup(
       }
     }
 
-    auto fnType = baseTy->getMetatypeInstanceType()->getTypeOfMember(
-        DC.getParentModule(), VD, declaredMemberType);
-
+    auto subs = baseTy->getMetatypeInstanceType()->getMemberSubstitutionMap(
+        DC.getParentModule(), VD,
+        VD->getInnermostDeclContext()->getGenericEnvironmentOfContext());
+    auto fnType = declaredMemberType.subst(subs, SubstFlags::UseErrorType);
     if (!fnType)
       continue;
 

test/IDE/complete_call_arg.swift

@@ -83,6 +83,8 @@
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=IMPLICIT_MEMBER_SECOND | %FileCheck %s -check-prefix=IMPLICIT_MEMBER_SECOND
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=IMPLICIT_MEMBER_SKIPPED | %FileCheck %s -check-prefix=IMPLICIT_MEMBER_SKIPPED
 
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=ARCHETYPE_GENERIC_1 | %FileCheck %s -check-prefix=ARCHETYPE_GENERIC_1
+
 var i1 = 1
 var i2 = 2
 var oi1 : Int?
@@ -686,3 +688,12 @@ func testImplicitMember() {
 // IMPLICIT_MEMBER_SKIPPED: Keyword/ExprSpecific:               arg4: [#Argument name#];
 // IMPLICIT_MEMBER_SKIPPED: End completions
 }
+
+struct Wrap<T> {
+  func method<U>(_ fn: (T) -> U) -> Wrap<U> {}
+}
+func testGenricMethodOnGenericOfArchetype<Wrapped>(value: Wrap<Wrapped>) {
+  value.method(#^ARCHETYPE_GENERIC_1^#)
+// ARCHETYPE_GENERIC_1: Begin completions
+// ARCHETYPE_GENERIC_1: Decl[InstanceMethod]/CurrNominal:   ['(']{#(fn): (Wrapped) -> _##(Wrapped) -> _#}[')'][#Wrap<_>#];
+}