RFR: JDK-8235621: Replace use of Function<?,Integer> with ToIntFunction

[Maurizio Cimadamore]

Looks good - while I understand the general point around contravariance, 
I think it's always a trade off between simplicity and completeness. In 
this case, using ? super buys you nothing (since there's no interesting 
Symbol supertype). Yes Remi, we can write examples where that bites, but 
I don't think that's important - and we can change if (and when) that 
becomes an issue.

Maurizio

On 10/12/2019 00:38, Jonathan Gibbons wrote:
> Following Rémi's suggestion[1], please review a trivial change to 
> javac to have it use ToIntFunction
> instead of Function<..., Integer> in the recent patch for JDK-8234689 
> [2].
>
> Patch inline below. No change to the original test is necessary.
>
> JBS: https://bugs.openjdk.java.net/browse/JDK-8235621
> [1] 
> https://mail.openjdk.java.net/pipermail/compiler-dev/2019-December/014043.html
> [2] https://hg.openjdk.java.net/jdk/jdk/rev/17b0f051280f
>
> -- Jon
>
> diff -r 2aaa8bcb90a9 -r 1e000f399f3a 
> src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/ClassWriter.java
>
> --- 
> a/src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/ClassWriter.java 
> Mon Dec 09 15:28:46 2019 +0100
> +++ 
> b/src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/ClassWriter.java 
> Mon Dec 09 16:12:42 2019 -0800
> @@ -30,7 +30,7 @@
>  import java.util.Map;
>  import java.util.Set;
>  import java.util.LinkedHashSet;
> -import java.util.function.Function;
> +import java.util.function.ToIntFunction;
>
>  import javax.tools.JavaFileManager;
>  import javax.tools.FileObject;
> @@ -114,7 +114,7 @@
>       */
>      public boolean multiModuleMode;
>
> -    private List<Function<Symbol, Integer>> extraAttributeHooks = 
> List.nil();
> +    private List<ToIntFunction<Symbol>> extraAttributeHooks = 
> List.nil();
>
>      /** The initial sizes of the data and constant pool buffers.
>       *  Sizes are increased when buffers get full.
> @@ -191,7 +191,7 @@
>          }
>      }
>
> -    public void addExtraAttributes(Function<Symbol, Integer> 
> addExtraAttributes) {
> +    public void addExtraAttributes(ToIntFunction<Symbol> 
> addExtraAttributes) {
>          extraAttributeHooks = 
> extraAttributeHooks.prepend(addExtraAttributes);
>      }
>
> @@ -1669,7 +1669,7 @@
>       */
>      protected int writeExtraAttributes(Symbol sym) {
>          int i = 0;
> -        for (Function<Symbol, Integer> hook : extraAttributeHooks) {
> +        for (ToIntFunction<Symbol> hook : extraAttributeHooks) {
>              i += hook.apply(sym);
>          }
>          return i;
>