Auto merge of rust-lang#119361 - sjwang05:issue-119352, r=WaffleLapkin

Fix ICE when suggesting dereferencing binop operands

Fixes rust-lang#119352

compiler/rustc_hir/src/lang_items.rs

@@ -374,3 +374,30 @@ pub static OPERATORS: &'static [LangItem] = &[
     LangItem::PartialEq,
     LangItem::PartialOrd,
 ];
+
+pub static BINARY_OPERATORS: &'static [LangItem] = &[
+    LangItem::Add,
+    LangItem::Sub,
+    LangItem::Mul,
+    LangItem::Div,
+    LangItem::Rem,
+    LangItem::BitXor,
+    LangItem::BitAnd,
+    LangItem::BitOr,
+    LangItem::Shl,
+    LangItem::Shr,
+    LangItem::AddAssign,
+    LangItem::SubAssign,
+    LangItem::MulAssign,
+    LangItem::DivAssign,
+    LangItem::RemAssign,
+    LangItem::BitXorAssign,
+    LangItem::BitAndAssign,
+    LangItem::BitOrAssign,
+    LangItem::ShlAssign,
+    LangItem::ShrAssign,
+    LangItem::Index,
+    LangItem::IndexMut,
+    LangItem::PartialEq,
+    LangItem::PartialOrd,
+];

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -859,6 +859,14 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             && let hir::Node::Expr(lhs) = self.tcx.hir_node(*lhs_hir_id)
             && let hir::Node::Expr(rhs) = self.tcx.hir_node(*rhs_hir_id)
             && let Some(rhs_ty) = typeck_results.expr_ty_opt(rhs)
+            && let trait_pred = predicate.unwrap_or(trait_pred)
+            // Only run this code on binary operators
+            && hir::lang_items::BINARY_OPERATORS
+                .iter()
+                .filter_map(|&op| self.tcx.lang_items().get(op))
+                .any(|op| {
+                    op == trait_pred.skip_binder().trait_ref.def_id
+                })
         {
             // Suggest dereferencing the LHS, RHS, or both terms of a binop if possible
 

tests/ui/binop/binary-op-suggest-deref.rs

@@ -72,4 +72,12 @@ fn baz() {
     //~^ERROR can't compare `str` with `&String` [E0277]
 }
 
+fn qux() {
+    // Issue #119352
+    const FOO: i32 = 42;
+    let _ = FOO & (*"Sized".to_string().into_boxed_str());
+    //~^ ERROR the size for values of type `str` cannot be known at compilation time
+    //~| ERROR no implementation for `i32 & str` [E0277]
+}
+
 fn main() {}

tests/ui/binop/binary-op-suggest-deref.stderr

@@ -295,7 +295,28 @@ help: consider dereferencing here
 LL |     _ = partial[..3] == *string_ref;
    |                         +
 
-error: aborting due to 22 previous errors
+error[E0277]: no implementation for `i32 & str`
+  --> $DIR/binary-op-suggest-deref.rs:78:17
+   |
+LL |     let _ = FOO & (*"Sized".to_string().into_boxed_str());
+   |                 ^ no implementation for `i32 & str`
+   |
+   = help: the trait `BitAnd<str>` is not implemented for `i32`
+   = help: the following other types implement trait `BitAnd<Rhs>`:
+             <i32 as BitAnd>
+             <i32 as BitAnd<&i32>>
+             <&'a i32 as BitAnd<i32>>
+             <&i32 as BitAnd<&i32>>
+
+error[E0277]: the size for values of type `str` cannot be known at compilation time
+  --> $DIR/binary-op-suggest-deref.rs:78:17
+   |
+LL |     let _ = FOO & (*"Sized".to_string().into_boxed_str());
+   |                 ^ doesn't have a size known at compile-time
+   |
+   = help: the trait `Sized` is not implemented for `str`
+
+error: aborting due to 24 previous errors
 
 Some errors have detailed explanations: E0277, E0308, E0369.
 For more information about an error, try `rustc --explain E0277`.