gccrs: Fix ICE when constant is missing and expression

This is an invalid test case and doesnt work with rustc, we dont fully pick
up the errors. Nr2 does handle this and puts out an extra good diagnostic
but the old NR doesnt so for now i added this to the exclude list and then
when we remove old name resolver this issue goes away.

Fixes #3642

gcc/rust/ChangeLog:

	* hir/rust-ast-lower-item.cc (ASTLoweringItem::visit): check for has_expr
	* hir/rust-hir-dump.cc (Dump::visit): likewise
	* hir/tree/rust-hir-item.h: add has_expr helper
	* resolve/rust-ast-resolve-item.cc (ResolveItem::visit): check for has_expr
	* resolve/rust-ast-resolve-stmt.h: likewise
	* typecheck/rust-hir-type-check-stmt.cc (TypeCheckStmt::visit): likewise

gcc/testsuite/ChangeLog:

	* rust/compile/nr2/exclude: nr2 puts out an extra error
	* rust/compile/issue-3642.rs: New test.

Signed-off-by: Philip Herron <[email protected]>

Author: philberty

gcc/rust/hir/rust-ast-lower-item.cc

@@ -367,7 +367,9 @@ ASTLoweringItem::visit (AST::ConstantItem &constant)
   HIR::Visibility vis = translate_visibility (constant.get_visibility ());
 
   HIR::Type *type = ASTLoweringType::translate (constant.get_type (), true);
-  HIR::Expr *expr = ASTLoweringExpr::translate (constant.get_expr ());
+  HIR::Expr *expr = nullptr;
+  if (constant.has_expr ())
+    expr = ASTLoweringExpr::translate (constant.get_expr ());
 
   auto crate_num = mappings.get_current_crate ();
   Analysis::NodeMapping mapping (crate_num, constant.get_node_id (),

gcc/rust/hir/rust-hir-dump.cc

@@ -1926,7 +1926,8 @@ Dump::visit (ConstantItem &e)
   do_vis_item (e);
   put_field ("identifier", e.get_identifier ().as_string ());
   visit_field ("type", e.get_type ());
-  visit_field ("const_expr", e.get_expr ());
+  if (e.has_expr ())
+    visit_field ("const_expr", e.get_expr ());
   end ("ConstantItem");
 }
 

gcc/rust/hir/tree/rust-hir-item.h

@@ -1797,6 +1797,8 @@ class ConstantItem : public VisItem, public ImplItem
     return *type;
   }
 
+  bool has_expr () const { return const_expr != nullptr; }
+
   Expr &get_expr () { return *const_expr; }
 
   Identifier get_identifier () const { return identifier; }

gcc/rust/resolve/rust-ast-resolve-item.cc

@@ -453,7 +453,8 @@ ResolveItem::visit (AST::ConstantItem &constant)
   resolve_visibility (constant.get_visibility ());
 
   ResolveType::go (constant.get_type ());
-  ResolveExpr::go (constant.get_expr (), path, cpath);
+  if (constant.has_expr ())
+    ResolveExpr::go (constant.get_expr (), path, cpath);
 }
 
 void

gcc/rust/resolve/rust-ast-resolve-stmt.h

@@ -67,7 +67,8 @@ class ResolveStmt : public ResolverBase
       });
 
     ResolveType::go (constant.get_type ());
-    ResolveExpr::go (constant.get_expr (), prefix, canonical_prefix);
+    if (constant.has_expr ())
+      ResolveExpr::go (constant.get_expr (), prefix, canonical_prefix);
   }
 
   void visit (AST::LetStmt &stmt) override

gcc/rust/typecheck/rust-hir-type-check-stmt.cc

@@ -60,6 +60,12 @@ void
 TypeCheckStmt::visit (HIR::ConstantItem &constant)
 {
   TyTy::BaseType *type = TypeCheckType::Resolve (constant.get_type ());
+  if (!constant.has_expr ())
+    {
+      infered = type;
+      return;
+    }
+
   TyTy::BaseType *expr_type = TypeCheckExpr::Resolve (constant.get_expr ());
 
   infered = coercion_site (

gcc/testsuite/rust/compile/issue-3642.rs

@@ -0,0 +1,9 @@
+#[lang = "sized"]
+trait Sized {}
+
+pub trait T<X> {
+    const D: i32 = {
+        // { dg-error "mismatched types, expected .i32. but got .()." "" { target *-*-* } .-1 }
+        const C: X;
+    };
+}

gcc/testsuite/rust/compile/nr2/exclude

@@ -4,4 +4,5 @@ issue-1487.rs
 issue-2015.rs
 issue-3454.rs
 impl_trait_generic_arg.rs
+issue-3642.rs
 # please don't delete the trailing newline