Assignment->lambda->statement fails with "statement enter $[ followed by statement enter $["

[fejesjoco]

Repro sample:

  public static void main(String[] args) {
    CodeBlock inner =
        CodeBlock.builder()
            .beginControlFlow("() ->")
            .addStatement("return 42")
            .endControlFlow()
            .build();
    System.err.println("<<<" + inner + ">>>");
    CodeBlock outer1 =
        CodeBlock.builder()
            .add(
                "$T lambda = $L;",
                ParameterizedTypeName.get(
                    ClassName.get(Supplier.class), ClassName.get(Integer.class)),
                inner)
            .build();
    System.err.println("<<<" + outer1 + ">>>");
    CodeBlock outer2 =
        CodeBlock.builder()
            .addStatement(
                "$T lambda = $L",
                ParameterizedTypeName.get(
                    ClassName.get(Supplier.class), ClassName.get(Integer.class)),
                inner)
            .build();
    System.err.println("<<<" + outer2 + ">>>");
  }

The first two prints work, the third fails:

<<<() -> {
  return 42;
}
>>>
<<<java.util.function.Supplier<java.lang.Integer> lambda = () -> {
  return 42;
}
;>>>
Exception in thread "main" java.lang.IllegalStateException: statement enter $[ followed by statement enter $[
	at com.squareup.javapoet.Util.checkState(Util.java:62)
	at com.squareup.javapoet.CodeWriter.emit(CodeWriter.java:284)
	at com.squareup.javapoet.CodeWriter.emit(CodeWriter.java:229)
	at com.squareup.javapoet.CodeWriter.emitLiteral(CodeWriter.java:365)
	at com.squareup.javapoet.CodeWriter.emit(CodeWriter.java:240)
	at com.squareup.javapoet.CodeWriter.emit(CodeWriter.java:229)
	at com.squareup.javapoet.CodeBlock.toString(CodeBlock.java:97)
	at java.base/java.lang.String.valueOf(String.java:2958)

I think this should work, because the assignment is a statement, and because of the lambda syntax the rvalue can also contain statements. But it seems like Javapoet is confused by statements within each other.

[coderstory]

            .addStatement(
                "$T lambda = $L",
                ParameterizedTypeName.get(
                    ClassName.get(Supplier.class), ClassName.get(Integer.class)),
                inner**.toString()**)

[WangXiequn]

#884 I try to do it in this pull request.