RFR: Generate missing null checks [v5]

[Maurizio Cimadamore]

On Fri, 9 Jan 2026 18:18:40 GMT, Vicente Romero <vromero at openjdk.org> wrote:

>> generate missing null checks like for method arguments, return arguments, etc
>
> Vicente Romero has updated the pull request incrementally with one additional commit since the last revision:
> 
>   last iteration

src/jdk.compiler/share/classes/com/sun/tools/javac/comp/NullChecksWriter.java line 88:

> 86: 
> 87:     JCExpression generateNullCheckIfNeeded(JCExpression tree, JCNullableTypeExpression.NullMarker expectedNullness) {
> 88:         if (expectedNullness == JCNullableTypeExpression.NullMarker.NOT_NULL && !types.isNonNullable(tree.type)) {

Isn't `types.isNonNullable(tree.type)` always false here? (since the type is erased)

src/jdk.compiler/share/classes/com/sun/tools/javac/comp/TransTypes.java line 910:

> 908:         tree.value.type = erasure(tree.value.type);
> 909:         tree.value = retype(tree.value, tree.value.type, pt);
> 910:         //result = generateNullCheckIfNeeded((JCExpression)result);

Leftover?

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PR Review Comment: https://git.openjdk.org/valhalla/pull/1867#discussion_r2677176468
PR Review Comment: https://git.openjdk.org/valhalla/pull/1867#discussion_r2677181461