Rollup merge of rust-lang#147421 - Kivooeo:ice-fix51621, r=chenyukang

Add check if span is from macro expansion

The same thing I did in rust-lang#147416, actually the same bug but in another place, I'm not really sure how this method is good for fixing such ICEs, but, it does work and not conflicting with any existing tests, so I guess, it's fine

Fixes rust-lang#147408

r? compiler

Author: matthiaskrgr

compiler/rustc_lint/src/shadowed_into_iter.rs

@@ -134,6 +134,8 @@ impl<'tcx> LateLintPass<'tcx> for ShadowedIntoIter {
             && let hir::ExprKind::Call(path, [_]) = &arg.kind
             && let hir::ExprKind::Path(hir::QPath::LangItem(hir::LangItem::IntoIterIntoIter, ..)) =
                 &path.kind
+            && !receiver_arg.span.from_expansion()
+            && !expr.span.from_expansion()
         {
             Some(ShadowedIntoIterDiagSub::RemoveIntoIter {
                 span: receiver_arg.span.shrink_to_hi().to(expr.span.shrink_to_hi()),

tests/ui/macros/macro-expansion-empty-span-147408.rs

@@ -0,0 +1,23 @@
+//@ check-pass
+
+fn main() {
+    macro_rules! mac {
+        (iter $e:expr) => {
+            $e.iter()
+        };
+        (into_iter $e:expr) => {
+            $e.into_iter() //~ WARN this method call resolves to
+            //~^ WARN this changes meaning in Rust 2021
+        };
+        (next $e:expr) => {
+            $e.iter().next()
+        };
+    }
+
+    for _ in dbg!([1, 2]).iter() {}
+    for _ in dbg!([1, 2]).into_iter() {} //~ WARN this method call resolves to
+    //~^ WARN this changes meaning in Rust 2021
+    for _ in mac!(iter [1, 2]) {}
+    for _ in mac!(into_iter [1, 2]) {}
+    for _ in mac!(next [1, 2]) {} //~ WARN for loop over an
+}

tests/ui/macros/macro-expansion-empty-span-147408.stderr

@@ -0,0 +1,58 @@
+ WARN rustc_errors::emitter Invalid span $SRC_DIR/std/src/macros.rs:LL:COL (#11), error=SourceNotAvailable { filename: Real(Remapped { local_path: None, virtual_name: "$SRC_DIR/std/src/macros.rs" }) }
+warning: this method call resolves to `<&[T; N] as IntoIterator>::into_iter` (due to backwards compatibility), but will resolve to `<[T; N] as IntoIterator>::into_iter` in Rust 2021
+  --> $DIR/macro-expansion-empty-span-147408.rs:18:27
+   |
+LL |     for _ in dbg!([1, 2]).into_iter() {}
+   |                           ^^^^^^^^^
+   |
+   = warning: this changes meaning in Rust 2021
+   = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/IntoIterator-for-arrays.html>
+   = note: `#[warn(array_into_iter)]` (part of `#[warn(rust_2021_compatibility)]`) on by default
+help: use `.iter()` instead of `.into_iter()` to avoid ambiguity
+   |
+LL -     for _ in dbg!([1, 2]).into_iter() {}
+LL +     for _ in dbg!([1, 2]).iter() {}
+   |
+
+warning: this method call resolves to `<&[T; N] as IntoIterator>::into_iter` (due to backwards compatibility), but will resolve to `<[T; N] as IntoIterator>::into_iter` in Rust 2021
+  --> $DIR/macro-expansion-empty-span-147408.rs:9:16
+   |
+LL |             $e.into_iter()
+   |                ^^^^^^^^^
+...
+LL |     for _ in mac!(into_iter [1, 2]) {}
+   |              ---------------------- in this macro invocation
+   |
+   = warning: this changes meaning in Rust 2021
+   = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/IntoIterator-for-arrays.html>
+   = note: this warning originates in the macro `mac` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: use `.iter()` instead of `.into_iter()` to avoid ambiguity
+   |
+LL -             $e.into_iter()
+LL +             $e.iter()
+   |
+help: or use `IntoIterator::into_iter(..)` instead of `.into_iter()` to explicitly iterate by value
+   |
+LL |             IntoIterator::into_iter($e.into_iter())
+   |             ++++++++++++++++++++++++              +
+
+warning: for loop over an `Option`. This is more readably written as an `if let` statement
+  --> $DIR/macro-expansion-empty-span-147408.rs:22:14
+   |
+LL |     for _ in mac!(next [1, 2]) {}
+   |              ^^^^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(for_loops_over_fallibles)]` on by default
+help: to iterate over `$e.iter()` remove the call to `next`
+   |
+LL -             $e.iter().next()
+LL +             .by_ref().next()
+   |
+help: consider using `if let` to clear intent
+   |
+LL -     for _ in mac!(next [1, 2]) {}
+LL +     if let Some(_) = mac!(next [1, 2]) {}
+   |
+
+warning: 3 warnings emitted
+