Rollup merge of #112063 - WaffleLapkin:test_incremental_ice, r=cjgillot

Add a test for issue 110457/incremental ICE with closures with the same span

Closes #110457

It's probably possible to minimize the test case more, considering that we now know the underlying reason for the ICE, but I didn't.

r? `@cjgillot`

tests/incremental/issue-110457-same-span-closures/auxiliary/egui_inspect_derive.rs

@@ -0,0 +1,90 @@
+// force-host
+// no-prefer-dynamic
+#![crate_type = "proc-macro"]
+
+extern crate proc_macro;
+
+use proc_macro::{Delimiter, Group, Ident, Literal, Punct, Spacing, Span, TokenStream, TokenTree};
+
+#[proc_macro]
+pub fn expand(_: TokenStream) -> TokenStream {
+    // Hand expansion/rewriting of
+    // ```
+    // quote! {
+    //     output_mut(|o| o.copied_text = "".into());
+    //     output_mut(|o| o.copied_text = format!("{:?}", self.tile_db));
+    // }.into()
+    // ```
+    stream([
+        ident("output_mut"),
+        group(
+            Delimiter::Parenthesis,
+            [
+                or(),
+                ident("o"),
+                or(),
+                ident("o"),
+                dot(),
+                ident("copied_text"),
+                eq(),
+                string(""),
+                dot(),
+                ident("into"),
+                group(Delimiter::Parenthesis, []),
+            ],
+        ),
+        semi(),
+        ident("output_mut"),
+        group(
+            Delimiter::Parenthesis,
+            [
+                or(),
+                ident("o"),
+                or(),
+                ident("o"),
+                dot(),
+                ident("copied_text"),
+                eq(),
+                ident("format"),
+                bang(),
+                group(
+                    Delimiter::Parenthesis,
+                    [string("{:?}"), comma(), ident("self"), dot(), ident("tile_db")],
+                ),
+            ],
+        ),
+        semi(),
+    ])
+}
+
+fn stream(s: impl IntoIterator<Item = TokenTree>) -> TokenStream {
+    s.into_iter().collect()
+}
+
+fn ident(i: &str) -> TokenTree {
+    TokenTree::Ident(Ident::new(i, Span::call_site()))
+}
+fn group(d: Delimiter, s: impl IntoIterator<Item = TokenTree>) -> TokenTree {
+    TokenTree::Group(Group::new(d, s.into_iter().collect()))
+}
+fn semi() -> TokenTree {
+    TokenTree::Punct(Punct::new(';', Spacing::Alone))
+}
+fn or() -> TokenTree {
+    TokenTree::Punct(Punct::new('|', Spacing::Alone))
+}
+fn dot() -> TokenTree {
+    TokenTree::Punct(Punct::new('.', Spacing::Alone))
+}
+fn eq() -> TokenTree {
+    TokenTree::Punct(Punct::new('=', Spacing::Alone))
+}
+fn bang() -> TokenTree {
+    TokenTree::Punct(Punct::new('!', Spacing::Alone))
+}
+fn comma() -> TokenTree {
+    TokenTree::Punct(Punct::new(',', Spacing::Alone))
+}
+fn string(s: &str) -> TokenTree {
+    TokenTree::Literal(Literal::string(s))
+}

tests/incremental/issue-110457-same-span-closures/main.rs

@@ -0,0 +1,47 @@
+// aux-build: egui_inspect_derive.rs
+// revisions: cpass1 cpass2
+
+extern crate egui_inspect_derive;
+
+pub struct TileDef {
+    pub layer: (),
+    #[cfg(cpass2)]
+    pub blend_graphic: String,
+}
+
+pub(crate) struct GameState {
+    pub(crate) tile_db: TileDb,
+}
+
+impl GameState {
+    fn inspect_mut(&mut self) {
+        egui_inspect_derive::expand! {}
+    }
+}
+
+fn new() -> GameState {
+    loop {}
+}
+
+fn main() {
+    let mut app = new();
+    app.inspect_mut();
+}
+// this is actually used
+pub struct TileDb {
+    unknown_bg: TileDef,
+}
+
+impl std::fmt::Debug for TileDb {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        loop {}
+    }
+}
+
+pub struct PlatformOutput {
+    pub copied_text: String,
+}
+
+pub fn output_mut<R>(writer: impl FnOnce(&mut PlatformOutput) -> R) -> R {
+    loop {}
+}