[fixes #2120] ecj was not generating explicit nullchecks for builder-setters.

test/transform/resource/after-delombok/BuilderWithNonNull.java

@@ -0,0 +1,40 @@
+class BuilderWithNonNull {
+	@lombok.NonNull
+	private final String id;
+	@java.lang.SuppressWarnings("all")
+	BuilderWithNonNull(@lombok.NonNull final String id) {
+		if (id == null) {
+			throw new java.lang.NullPointerException("id is marked non-null but is null");
+		}
+		this.id = id;
+	}
+	@java.lang.SuppressWarnings("all")
+	public static class BuilderWithNonNullBuilder {
+		@java.lang.SuppressWarnings("all")
+		private String id;
+		@java.lang.SuppressWarnings("all")
+		BuilderWithNonNullBuilder() {
+		}
+		@java.lang.SuppressWarnings("all")
+		public BuilderWithNonNullBuilder id(@lombok.NonNull final String id) {
+			if (id == null) {
+				throw new java.lang.NullPointerException("id is marked non-null but is null");
+			}
+			this.id = id;
+			return this;
+		}
+		@java.lang.SuppressWarnings("all")
+		public BuilderWithNonNull build() {
+			return new BuilderWithNonNull(id);
+		}
+		@java.lang.Override
+		@java.lang.SuppressWarnings("all")
+		public java.lang.String toString() {
+			return "BuilderWithNonNull.BuilderWithNonNullBuilder(id=" + this.id + ")";
+		}
+	}
+	@java.lang.SuppressWarnings("all")
+	public static BuilderWithNonNullBuilder builder() {
+		return new BuilderWithNonNullBuilder();
+	}
+}