[CodeCompletion] Improve context type analysis for ternary expressions

This improves code-completion for non-type-checked ternary expressions.

Author: rintaro

lib/IDE/ExprContextAnalysis.cpp

@@ -645,6 +645,18 @@ class ExprContextAnalyzer {
       }
       break;
     }
+    case ExprKind::If: {
+      auto *IE = cast<IfExpr>(Parent);
+      if (SM.rangeContains(IE->getCondExpr()->getSourceRange(),
+                           ParsedExpr->getSourceRange())) {
+        recordPossibleType(Context.getBoolDecl()->getDeclaredInterfaceType());
+        break;
+      }
+      ExprContextInfo ternaryCtxtInfo(DC, Parent);
+      for (auto ternaryT : ternaryCtxtInfo.getPossibleTypes())
+        recordPossibleType(ternaryT);
+      break;
+    }
     case ExprKind::Assign: {
       auto *AE = cast<AssignExpr>(Parent);
 
@@ -861,7 +873,7 @@ class ExprContextAnalyzer {
         case ExprKind::Assign:
         case ExprKind::Array:
         case ExprKind::Dictionary:
-          return true;
+        case ExprKind::If:
         case ExprKind::UnresolvedMember:
           return true;
         case ExprKind::Tuple: {

test/IDE/complete_unresolved_members.swift

@@ -119,6 +119,9 @@
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=TERNARY_2 | %FileCheck %s -check-prefix=UNRESOLVED_3
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=TERNARY_3 | %FileCheck %s -check-prefix=UNRESOLVED_3
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=TERNARY_4 | %FileCheck %s -check-prefix=UNRESOLVED_3
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=TERNARY_5 | %FileCheck %s -check-prefix=UNRESOLVED_3
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=TERNARY_6 | %FileCheck %s -check-prefix=UNRESOLVED_3
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=TERNARY_CONDITION | %FileCheck %s -check-prefix=TERNARY_CONDITION
 
 enum SomeEnum1 {
   case South
@@ -738,12 +741,23 @@ func testTypeParamInContextType() {
 // TYPEPARAM_IN_CONTEXTTYPE_1: End completions
 }
 
-func testTernaryOperator() {
-  let _: SomeEnum1 = true ? .#^TERNARY_1^#
+func testTernaryOperator(cond: Bool) {
+  let _: SomeEnum1 = cond ? .#^TERNARY_1^#
   func sync(){}
-  let _: SomeEnum1 = true ? .#^TERNARY_2^# :
+  let _: SomeEnum1 = cond ? .#^TERNARY_2^# :
   func sync(){}
-  let _: SomeEnum1 = true ? .#^TERNARY_3^# : .South
+  let _: SomeEnum1 = cond ? .#^TERNARY_3^# : .South
   func sync(){}
-  let _: SomeEnum1 = true ? .South : .#^TERNARY_4^#
+  let _: SomeEnum1 = cond ? .South : .#^TERNARY_4^#
+}
+
+func testTernaryOperator2(cond: Bool) {
+  let _: SomeEnum1 = cond ? .#^TERNARY_5^# : .bogus
+  func sync(){}
+  let _: SomeEnum1 = cond ? .bogus : .#^TERNARY_6^#
+  func sync(){}
+  let _: SomeEnum1 = .#^TERNARY_CONDITION^# ? .bogus : .bogus
+// TERNARY_CONDITION: Begin completions
+// TERNARY_CONDITION-DAG: Decl[Constructor]/CurrNominal/TypeRelation[Identical]: init()[#Bool#]; name=init()
+// TERNARY_CONDITION: End completions
 }