Implement type inference of method invocations in Fasta.

pkg/front_end/testcases/inference/inferred_type_custom_unary_op_via_interface.dart.strong.expect

Index: pkg/front_end/testcases/inference/inferred_type_custom_unary_op_via_interface.dart.strong.expect
diff --git a/pkg/front_end/testcases/inference/inferred_type_custom_unary_op_via_interface.dart.strong.expect b/pkg/front_end/testcases/inference/inferred_type_custom_unary_op_via_interface.dart.strong.expect
new file mode 100644
index 0000000000000000000000000000000000000000..d1bfed5deb7a95dd6700d90d8406227b4366c670
--- /dev/null
+++ b/pkg/front_end/testcases/inference/inferred_type_custom_unary_op_via_interface.dart.strong.expect
@@ -0,0 +1,21 @@
+library test;
+import self as self;
+import "dart:core" as core;
+
+class I extends core::Object {
+  constructor •() → void
+    : super core::Object::•()
+    ;
+  operator unary-() → core::bool
+    return true;
+}
+abstract class C extends core::Object implements self::I {
+  constructor •() → void
+    : super core::Object::•()
+    ;
+}
+static field self::C c;
+static field core::bool x = self::c.unary-();
+static method main() → dynamic {
+  self::c;
+}