Implement type inference for "not" expressions.

pkg/front_end/lib/src/fasta/kernel/kernel_shadow_ast.dart

Index: pkg/front_end/lib/src/fasta/kernel/kernel_shadow_ast.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/kernel_shadow_ast.dart b/pkg/front_end/lib/src/fasta/kernel/kernel_shadow_ast.dart
index d7a6e08773506db04b2cad3f8b7b518dc96bc474..c9f70553c2adb14c57d0dd8c56cd76d2f8f79e43 100644
--- a/pkg/front_end/lib/src/fasta/kernel/kernel_shadow_ast.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/kernel_shadow_ast.dart
@@ -1301,14 +1301,20 @@ class KernelNot extends Not implements KernelExpression {
 
   @override
   void _collectDependencies(KernelDependencyCollector collector) {
-    // No inference dependencies.
+    collector.collectDependencies(operand);
   }
 
   @override
   DartType _inferExpression(
       KernelTypeInferrer inferrer, DartType typeContext, bool typeNeeded) {
-    // TODO(scheglov): implement.
-    return typeNeeded ? const DynamicType() : null;
+    typeNeeded = inferrer.listener.notEnter(this, typeContext) || typeNeeded;
+    // First infer the receiver so we can look up the method that was invoked.
+    inferrer.inferExpression(
+        operand, inferrer.coreTypes.boolClass.rawType, false);

[scheglov, 2017/06/12 23:29:28]

Maybe extract boolType into a local variable.

[Paul Berry, 2017/06/13 00:39:54]

Done.

+    DartType inferredType =
+        typeNeeded ? inferrer.coreTypes.boolClass.rawType : null;
+    inferrer.listener.notExit(this, inferredType);
+    return inferredType;
   }
 }