Infer types of bool/null/string literals.

pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart

Index: pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart
diff --git a/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart b/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart
index ff133dd3939abdd2f2067b2618bb960c3754b9f8..28edb199bae95470d92d03f9e014c097176e8bdc 100644
--- a/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart
+++ b/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart
@@ -78,6 +78,14 @@ abstract class TypeInferrerImpl<S, E, V, F> extends TypeInferrer<S, E, V, F> {
   /// initializer.
   E getFieldInitializer(F field);
 
+  /// Performs the core type inference algorithm for boolean literals.
+  ///
+  /// [typeContext], [typeNeeded], and the return value behave as described in
+  /// [inferExpression].
+  DartType inferBoolLiteral(DartType typeContext, bool typeNeeded) {
+    return typeNeeded ? coreTypes.boolClass.rawType : null;
+  }
+
   /// Performs the core type inference algorithm for double literals.
   ///
   /// [typeContext], [typeNeeded], and the return value behave as described in
@@ -201,6 +209,14 @@ abstract class TypeInferrerImpl<S, E, V, F> extends TypeInferrer<S, E, V, F> {
     return typeNeeded ? getterType : null;
   }
 
+  /// Performs the core type inference algorithm for string literals.
+  ///
+  /// [typeContext], [typeNeeded], and the return value behave as described in
+  /// [inferExpression].
+  DartType inferStringLiteral(DartType typeContext, bool typeNeeded) {
+    return typeNeeded ? coreTypes.stringClass.rawType : null;
+  }
+
   /// Performs the core type inference algorithm for variable declarations.
   ///
   /// [declaredType] is the declared type of the variable, or `null` if the type