Rollup merge of #89473 - FabianWolff:issue-89469, r=joshtriplett

Fix extra `non_snake_case` warning for shorthand field bindings

Fixes #89469. The problem is the innermost `if` condition here:
d14731cb3c/compiler/rustc_lint/src/nonstandard_style.rs (L435-L452)

This code runs for every `PatKind::Binding`, so if a struct has multiple fields, say A and B, and both are bound in a pattern using shorthands, the call to `self.check_snake_case()` will indeed be skipped in the `check_pat()` call for `A`; but when `check_pat()` is called for `B`, the loop will still iterate over `A`, and `field.ident (= A) != ident (= B)` will be true. I have fixed this by only looking at non-shorthand bindings, and only the binding that `check_pat()` was actually called for.

src/test/ui/lint/issue-89469.rs

@@ -0,0 +1,20 @@
+// Regression test for #89469, where an extra non_snake_case warning was
+// reported for a shorthand field binding.
+
+// check-pass
+#![deny(non_snake_case)]
+
+#[allow(non_snake_case)]
+struct Entry {
+    A: u16,
+    a: u16
+}
+
+fn foo() -> Entry {todo!()}
+
+pub fn f() {
+    let Entry { A, a } = foo();
+    let _ = (A, a);
+}
+
+fn main() {}