gccrs: Fix ICE when compiling block expressions in array capacity

We need to reuse the existing compile_constant_item helper which handles
the case if this is a simple expression, fn-call or a block expression.
The patch extracts out this helper as a static method so this can be used
in more places.

Fixes Rust-GCC#3566

gcc/rust/ChangeLog:

	* backend/rust-compile-base.cc (HIRCompileBase::address_expression): new helper constexpr
	* backend/rust-compile-base.h: prototype
	* backend/rust-compile-type.cc (TyTyResolveCompile::visit): call constexpr helper

gcc/testsuite/ChangeLog:

	* rust/compile/issue-3566-1.rs: New test.
	* rust/compile/issue-3566-2.rs: New test.

Signed-off-by: Philip Herron <herron.philip@googlemail.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/gcc/rust/backend/rust-compile-base.cc b/gcc/rust/backend/rust-compile-base.cc
index a4d0d06..c71417d 100644
--- a/gcc/rust/backend/rust-compile-base.cc
+++ b/gcc/rust/backend/rust-compile-base.cc
@@ -561,6 +561,18 @@ HIRCompileBase::address_expression (tree expr, location_t location)
 }
 
 tree
+HIRCompileBase::compile_constant_expr (
+  Context *ctx, HirId coercion_id, TyTy::BaseType *resolved_type,
+  TyTy::BaseType *expected_type, const Resolver::CanonicalPath &canonical_path,
+  HIR::Expr &const_value_expr, location_t locus, location_t expr_locus)
+{
+  HIRCompileBase c (ctx);
+  return c.compile_constant_item (coercion_id, resolved_type, expected_type,
+				  canonical_path, const_value_expr, locus,
+				  expr_locus);
+}
+
+tree
 HIRCompileBase::indirect_expression (tree expr, location_t locus)
 {
   if (expr == error_mark_node)