Merge #1022 #1033

1022: attribute expansion: Fix spurious stripping of tail expression r=CohenArthur a=CohenArthur

This commit fixes the issue reported in #391, but highlights another
one, which will be reported.

Closes #391 

1033: Fix bad copy-paste in can equal interface for pointer types r=philberty a=philberty

When we perform method resolution we check if the self arguments can be
matched. Here the bug was that pointer types had a bad vistitor and only
could ever match reference types which is wrong and was a copy paste error.

Fixes #1031
Addresses #849 


Co-authored-by: Arthur Cohen <arthur.cohen@embecosm.com>
Co-authored-by: Philip Herron <philip.herron@embecosm.com>

gcc/rust/ast/rust-ast.h

@@ -249,7 +249,8 @@ public:
     BYTE_STRING,
     INT,
     FLOAT,
-    BOOL
+    BOOL,
+    ERROR
   };
 
 private:
@@ -274,11 +275,11 @@ public:
 
   static Literal create_error ()
   {
-    return Literal ("", CHAR, PrimitiveCoreType::CORETYPE_UNKNOWN);
+    return Literal ("", ERROR, PrimitiveCoreType::CORETYPE_UNKNOWN);
   }
 
   // Returns whether literal is in an invalid state.
-  bool is_error () const { return value_as_string == ""; }
+  bool is_error () const { return type == ERROR; }
 };
 
 /* Forward decl - definition moved to rust-expr.h as it requires LiteralExpr to

gcc/rust/hir/rust-ast-lower-expr.h

@@ -359,6 +359,10 @@ public:
       case AST::Literal::LitType::BOOL:
 	type = HIR::Literal::LitType::BOOL;
 	break;
+	// Error literals should have been stripped during expansion
+      case AST::Literal::LitType::ERROR:
+	gcc_unreachable ();
+	break;
       }
     auto crate_num = mappings->get_current_crate ();
     Analysis::NodeMapping mapping (crate_num, expr.get_node_id (),

gcc/rust/typecheck/rust-tyty-cmp.h

@@ -1240,7 +1240,7 @@ public:
     : BaseCmp (base, emit_errors), base (base)
   {}
 
-  void visit (const ReferenceType &type) override
+  void visit (const PointerType &type) override
   {
     auto base_type = base->get_base ();
     auto other_base_type = type.get_base ();

gcc/testsuite/rust/compile/issue-1031.rs

@@ -0,0 +1,16 @@
+extern "rust-intrinsic" {
+    pub fn offset<T>(dst: *const T, offset: isize) -> *const T;
+}
+
+#[lang = "const_ptr"]
+impl<T> *const T {
+    pub const unsafe fn offset(self, count: isize) -> *const T {
+        // { dg-warning "associated function is never used" "" { target *-*-* } .-1 }
+        unsafe { offset(self, count) }
+    }
+
+    pub const unsafe fn add(self, count: usize) -> Self {
+        // { dg-warning "associated function is never used" "" { target *-*-* } .-1 }
+        unsafe { self.offset(count as isize) }
+    }
+}

gcc/testsuite/rust/compile/xfail/slice1.rs

@@ -1,3 +1,5 @@
-fn foo (e: &str) -> &str {
-    &"" // { dg-bogus "cannot strip expression in this position - outer attributes not allowed" "#391" { xfail *-*-* } }
+// { dg-additional-options "-w" }
+
+fn foo(e: &str) -> &str { // { dg-bogus "expected" "#391" { xfail *-*-* } }
+    &"" // { dg-bogus "expected" "#391" { xfail *-*-* } }
 }