[CodeCompletion] Expr context type analysis for failed array literal expr

let _: [Foo] = [
  .create(str: Int)
  .create(#^COMPLETE^#)
]

Previously, this completion used to fail because the array expression
isn't typechecked. We need to analyze the context type of the array
literal first, that defines the type of the unresolved member
expression.

rdar://problem/50696432

Author: rintaro

lib/IDE/ExprContextAnalysis.cpp

@@ -583,6 +583,15 @@ class ExprContextAnalyzer {
     case ExprKind::Array: {
       if (auto type = ParsedExpr->getType()) {
         recordPossibleType(type);
+        break;
+      }
+
+      // Check context types of the array literal expression.
+      ExprContextInfo arrayCtxtInfo(DC, Parent);
+      for (auto arrayT : arrayCtxtInfo.getPossibleTypes()) {
+        if (auto boundGenericT = arrayT->getAs<BoundGenericType>())
+          if (boundGenericT->getDecl() == Context.getArrayDecl())
+            recordPossibleType(boundGenericT->getGenericArgs()[0]);
       }
       break;
     }

test/IDE/complete_call_arg.swift

@@ -82,6 +82,14 @@
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=IMPLICIT_MEMBER_AFTERPAREN_2 | %FileCheck %s -check-prefix=IMPLICIT_MEMBER_AFTERPAREN_2
 // 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=IMPLICIT_MEMBER_ARRAY_1_AFTERPAREN_1 | %FileCheck %s -check-prefix=IMPLICIT_MEMBER_AFTERPAREN_1
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=IMPLICIT_MEMBER_ARRAY_1_AFTERPAREN_2 | %FileCheck %s -check-prefix=IMPLICIT_MEMBER_AFTERPAREN_2
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=IMPLICIT_MEMBER_ARRAY_1_SECOND | %FileCheck %s -check-prefix=IMPLICIT_MEMBER_SECOND
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=IMPLICIT_MEMBER_ARRAY_1_SKIPPED | %FileCheck %s -check-prefix=IMPLICIT_MEMBER_SKIPPED
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=IMPLICIT_MEMBER_ARRAY_2_AFTERPAREN_1 | %FileCheck %s -check-prefix=IMPLICIT_MEMBER_AFTERPAREN_1
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=IMPLICIT_MEMBER_ARRAY_2_AFTERPAREN_2 | %FileCheck %s -check-prefix=IMPLICIT_MEMBER_AFTERPAREN_2
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=IMPLICIT_MEMBER_ARRAY_2_SECOND | %FileCheck %s -check-prefix=IMPLICIT_MEMBER_SECOND
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=IMPLICIT_MEMBER_ARRAY_2_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
 
@@ -688,6 +696,39 @@ func testImplicitMember() {
 // IMPLICIT_MEMBER_SKIPPED: Keyword/ExprSpecific:               arg4: [#Argument name#];
 // IMPLICIT_MEMBER_SKIPPED: End completions
 }
+func testImplicitMemberInArrayLiteral() {
+  struct Receiver {
+    init(_: [TestStaticMemberCall]) {}
+    init(arg1: Int, arg2: [TestStaticMemberCall]) {}
+  }
+
+  Receiver([
+    .create1(x: 1),
+    .create1(#^IMPLICIT_MEMBER_ARRAY_1_AFTERPAREN_1^#),
+    // Same as IMPLICIT_MEMBER_AFTERPAREN_1.
+  ])
+  Receiver([
+    .create2(#^IMPLICIT_MEMBER_ARRAY_1_AFTERPAREN_2^#),
+    // Same as IMPLICIT_MEMBER_AFTERPAREN_2.
+    .create2(1, #^IMPLICIT_MEMBER_ARRAY_1_SECOND^#
+    // Same as IMPLICIT_MEMBER_SECOND.
+  ])
+  Receiver(arg1: 12, arg2: [
+    .create2(1, arg3: 2, #^IMPLICIT_MEMBER_ARRAY_1_SKIPPED^#
+    // Same as IMPLICIT_MEMBER_SKIPPED.
+    .create1(x: 12)
+  ])
+  let _: [TestStaticMemberCall] = [
+    .create1(#^IMPLICIT_MEMBER_ARRAY_2_AFTERPAREN_1^#),
+    // Same as STATIC_METHOD_AFTERPAREN_1.
+    .create2(#^IMPLICIT_MEMBER_ARRAY_2_AFTERPAREN_2^#),
+    // Same as STATIC_METHOD_AFTERPAREN_2.
+    .create2(1, #^IMPLICIT_MEMBER_ARRAY_2_SECOND^#),
+    // Same as STATIC_METHOD_SECOND.
+    .create2(1, arg3: 2, #^IMPLICIT_MEMBER_ARRAY_2_SKIPPED^#),
+    // Same as STATIC_METHOD_SKIPPED.
+  ]
+}
 
 struct Wrap<T> {
   func method<U>(_ fn: (T) -> U) -> Wrap<U> {}