Fix ICE with duplicate hirid on autoderef coercion site mappings

Imagine the call expression:

  Foo(a+b)

But the a+b is an operator overload of the assignment operation. We store
the autoderef coercions on the HIR id of the plus_expression here which is
going to conflict with the id used to store the autoderef coercions the
argument a+b. So this patch changes that all autoderef coercions store the
autoderef for the implicit method call on the hirid of the lvalue hirid
which in this case is 'a'. This means we won't conflict and cause an ICE
in this case.

3 files changed, 23 insertions, 7 deletions

diff --git a/gcc/rust/backend/rust-compile-expr.cc b/gcc/rust/backend/rust-compile-expr.cc
index 92c224c..35861c1 100644
--- a/gcc/rust/backend/rust-compile-expr.cc
+++ b/gcc/rust/backend/rust-compile-expr.cc
@@ -1285,7 +1285,7 @@ CompileExpr::resolve_operator_overload (
   // lookup the autoderef mappings
   std::vector<Resolver::Adjustment> *adjustments = nullptr;
   ok = ctx->get_tyctx ()->lookup_autoderef_mappings (
-    expr.get_mappings ().get_hirid (), &adjustments);
+    expr.get_lvalue_mappings ().get_hirid (), &adjustments);
   rust_assert (ok);
 
   // apply adjustments for the fn call
diff --git a/gcc/rust/hir/tree/rust-hir-expr.h b/gcc/rust/hir/tree/rust-hir-expr.h
index d16ac92..7cb86a6 100644
--- a/gcc/rust/hir/tree/rust-hir-expr.h
+++ b/gcc/rust/hir/tree/rust-hir-expr.h
@@ -4120,31 +4120,47 @@ class OperatorExprMeta
 {
 public:
   OperatorExprMeta (HIR::CompoundAssignmentExpr &expr)
-    : node_mappings (expr.get_mappings ()), locus (expr.get_locus ())
+    : node_mappings (expr.get_mappings ()),
+      lvalue_mappings (expr.get_expr ()->get_mappings ()),
+      locus (expr.get_locus ())
   {}
 
   OperatorExprMeta (HIR::ArithmeticOrLogicalExpr &expr)
-    : node_mappings (expr.get_mappings ()), locus (expr.get_locus ())
+    : node_mappings (expr.get_mappings ()),
+      lvalue_mappings (expr.get_expr ()->get_mappings ()),
+      locus (expr.get_locus ())
   {}
 
   OperatorExprMeta (HIR::NegationExpr &expr)
-    : node_mappings (expr.get_mappings ()), locus (expr.get_locus ())
+    : node_mappings (expr.get_mappings ()),
+      lvalue_mappings (expr.get_expr ()->get_mappings ()),
+      locus (expr.get_locus ())
   {}
 
   OperatorExprMeta (HIR::DereferenceExpr &expr)
-    : node_mappings (expr.get_mappings ()), locus (expr.get_locus ())
+    : node_mappings (expr.get_mappings ()),
+      lvalue_mappings (expr.get_expr ()->get_mappings ()),
+      locus (expr.get_locus ())
   {}
 
   OperatorExprMeta (HIR::ArrayIndexExpr &expr)
-    : node_mappings (expr.get_mappings ()), locus (expr.get_locus ())
+    : node_mappings (expr.get_mappings ()),
+      lvalue_mappings (expr.get_array_expr ()->get_mappings ()),
+      locus (expr.get_locus ())
   {}
 
   const Analysis::NodeMapping &get_mappings () const { return node_mappings; }
 
+  const Analysis::NodeMapping &get_lvalue_mappings () const
+  {
+    return lvalue_mappings;
+  }
+
   Location get_locus () const { return locus; }
 
 private:
   const Analysis::NodeMapping node_mappings;
+  const Analysis::NodeMapping lvalue_mappings;
   Location locus;
 };
 
diff --git a/gcc/rust/typecheck/rust-hir-type-check-expr.cc b/gcc/rust/typecheck/rust-hir-type-check-expr.cc
index d96a85c..80f351a 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-expr.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-expr.cc
@@ -365,7 +365,7 @@ TypeCheckExpr::resolve_operator_overload (
     }
 
   // store the adjustments for code-generation to know what to do
-  context->insert_autoderef_mappings (expr.get_mappings ().get_hirid (),
+  context->insert_autoderef_mappings (expr.get_lvalue_mappings ().get_hirid (),
 				      std::move (candidate.adjustments));
 
   // now its just like a method-call-expr