[CodeCompletion] Check if stdlib decls exist

In some configurations e.g. 'Embedded', some stdlib types don't exist.
We cannot just assume they are always available.

rdar://119691781

Author: rintaro

lib/IDE/CompletionLookup.cpp

@@ -83,8 +83,12 @@ static Type defaultTypeLiteralKind(CodeCompletionLiteralKind kind,
   case CodeCompletionLiteralKind::StringLiteral:
     return Ctx.getStringType();
   case CodeCompletionLiteralKind::ArrayLiteral:
+    if (!Ctx.getArrayDecl())
+      return Type();
     return Ctx.getArrayDecl()->getDeclaredType();
   case CodeCompletionLiteralKind::DictionaryLiteral:
+    if (!Ctx.getDictionaryDecl())
+      return Type();
     return Ctx.getDictionaryDecl()->getDeclaredType();
   case CodeCompletionLiteralKind::NilLiteral:
   case CodeCompletionLiteralKind::ColorLiteral:

test/IDE/complete_embedded.swift

@@ -0,0 +1,14 @@
+// REQUIRES: asserts
+// REQUIRES: swift_in_compiler
+// RUN: %batch-code-completion -enable-experimental-feature Embedded
+
+func test() {
+  #^GLOBAL^#
+// GLOBAL: Literal[Integer]/None:              0[#Int#];
+// GLOBAL: Literal[Boolean]/None:              true[#Bool#];
+// GLOBAL: Literal[Boolean]/None:              false[#Bool#];
+// GLOBAL: Literal[Nil]/None:                  nil;
+// GLOBAL: Literal[String]/None:               "{#(abc)#}"[#String#];
+// GLOBAL: Literal[Array]/None:                [{#(values)#}][#Array#];
+// GLOBAL: Literal[Dictionary]/None:           [{#(key)#}: {#(value)#}];
+}

tools/swift-ide-test/swift-ide-test.cpp

@@ -4359,6 +4359,20 @@ int main(int argc, char *argv[]) {
   for (auto &File : options::InputFilenames)
     InitInvok.getFrontendOptions().InputsAndOutputs.addInputFile(File);
 
+  for (const auto &featureArg : options::EnableExperimentalFeatures) {
+    if (auto feature = getExperimentalFeature(featureArg)) {
+      InitInvok.getLangOptions().Features.insert(*feature);
+    }
+  }
+
+  for (const auto &featureArg : options::EnableUpcomingFeatures) {
+    if (auto feature = getUpcomingFeature(featureArg)) {
+      InitInvok.getLangOptions().Features.insert(*feature);
+    }
+  }
+
+  // NOTE: 'setMainExecutablePath' must be after 'Features' because
+  // 'setRuntimeResourcePath()' called from here depends on 'Features'.
   InitInvok.setMainExecutablePath(mainExecutablePath);
   InitInvok.setModuleName(options::ModuleName);
 
@@ -4428,18 +4442,6 @@ int main(int argc, char *argv[]) {
     InitInvok.getLangOptions().EnableExperimentalStringProcessing = true;
   }
 
-  for (const auto &featureArg : options::EnableExperimentalFeatures) {
-    if (auto feature = getExperimentalFeature(featureArg)) {
-      InitInvok.getLangOptions().Features.insert(*feature);
-    }
-  }
-
-  for (const auto &featureArg : options::EnableUpcomingFeatures) {
-    if (auto feature = getUpcomingFeature(featureArg)) {
-      InitInvok.getLangOptions().Features.insert(*feature);
-    }
-  }
-
   if (!options::Triple.empty())
     InitInvok.setTargetTriple(options::Triple);
   if (!options::SwiftVersion.empty()) {