RFR: 7903132: Replace casts with type test pattern

[Jorn Vernee]

On Thu, 24 Mar 2022 22:48:41 GMT, Ethan McCue <duke at openjdk.java.net> wrote:

> Replaces a handful of casts following type tests with the equivalent pattern syntax.
> 
> I cannot create a matching issue, as I do not have an account on the bug tracker.

I've filed an issue for this PR here: https://bugs.openjdk.java.net/browse/CODETOOLS-7903132 Please update the PR title to include the issue number.

src/main/java/org/openjdk/jextract/clang/Cursor.java line 243:

> 241:             return false;
> 242:         }
> 243:         return (Index_h.clang_equalCursors(cursor, otherCursor.cursor) != 0);

I think in these cases we can do better by merging the `instanceof` check above this in the condition. i.e.
Suggestion:

        return other instanceof Cursor otherCursor
            && (Index_h.clang_equalCursors(cursor, otherCursor.cursor) != 0);


And similar for other places that are computing a boolean value, such as all the equals methods.

src/main/java/org/openjdk/jextract/impl/ClassSourceBuilder.java line 59:

> 57:     ClassSourceBuilder(JavaSourceBuilder enclosing, Kind kind, String name) {
> 58:         this.enclosing = enclosing;
> 59:         this.align = (enclosing instanceof ClassSourceBuilder enclosing) ? enclosing.align : 0;

This is resulting in a compilation error:

jextract\src\main\java\org\openjdk\jextract\impl\ClassSourceBuilder.java:59: error: variable enclosing is already defined in constructor ClassSourceBuilder(JavaSourceBuilder,Kind,String)
        this.align = (enclosing instanceof ClassSourceBuilder enclosing) ? enclosing.align : 0;

Please build and test the patch locally on your machine as well, if you haven't done so already. (This should be done before suggesting changes).

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PR: https://git.openjdk.java.net/jextract/pull/5