diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs index 6e62c49224314..377416aa057c0 100644 --- a/src/librustc_typeck/check/mod.rs +++ b/src/librustc_typeck/check/mod.rs @@ -3151,14 +3151,22 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> { fn check_expr_struct_fields(&self, adt_ty: Ty<'tcx>, + expected: Expectation<'tcx>, expr_id: ast::NodeId, span: Span, variant: &'tcx ty::VariantDef, ast_fields: &'gcx [hir::Field], check_completeness: bool) { let tcx = self.tcx; - let (substs, adt_kind, kind_name) = match adt_ty.sty { - ty::TyAdt(adt, substs) => (substs, adt.adt_kind(), adt.variant_descr()), + + let adt_ty_hint = + self.expected_inputs_for_expected_output(span, expected, adt_ty, &[adt_ty]) + .get(0).cloned().unwrap_or(adt_ty); + + let (substs, hint_substs, adt_kind, kind_name) = match (&adt_ty.sty, &adt_ty_hint.sty) { + (&ty::TyAdt(adt, substs), &ty::TyAdt(_, hint_substs)) => { + (substs, hint_substs, adt.adt_kind(), adt.variant_descr()) + } _ => span_bug!(span, "non-ADT passed to check_expr_struct_fields") }; @@ -3173,10 +3181,12 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> { // Typecheck each field. for field in ast_fields { - let expected_field_type; + let final_field_type; + let field_type_hint; if let Some(v_field) = remaining_fields.remove(&field.name.node) { - expected_field_type = self.field_ty(field.span, v_field, substs); + final_field_type = self.field_ty(field.span, v_field, substs); + field_type_hint = self.field_ty(field.span, v_field, hint_substs); seen_fields.insert(field.name.node, field.span); @@ -3188,7 +3198,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> { } } else { error_happened = true; - expected_field_type = tcx.types.err; + final_field_type = tcx.types.err; + field_type_hint = tcx.types.err; if let Some(_) = variant.find_field_named(field.name.node) { let mut err = struct_span_err!(self.tcx.sess, field.name.span, @@ -3210,7 +3221,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> { // Make sure to give a type to the field even if there's // an error, so we can continue typechecking - self.check_expr_coercable_to_type(&field.expr, expected_field_type); + let ty = self.check_expr_with_hint(&field.expr, field_type_hint); + self.demand_coerce(&field.expr, ty, final_field_type); } // Make sure the programmer specified correct number of fields. @@ -3320,6 +3332,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> { fn check_expr_struct(&self, expr: &hir::Expr, + expected: Expectation<'tcx>, qpath: &hir::QPath, fields: &'gcx [hir::Field], base_expr: &'gcx Option
>) -> Ty<'tcx>
@@ -3338,7 +3351,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
hir::QPath::TypeRelative(ref qself, _) => qself.span
};
- self.check_expr_struct_fields(struct_ty, expr.id, path_span, variant, fields,
+ self.check_expr_struct_fields(struct_ty, expected, expr.id, path_span, variant, fields,
base_expr.is_none());
if let &Some(ref base_expr) = base_expr {
self.check_expr_has_type(base_expr, struct_ty);
@@ -3883,7 +3896,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
}
}
hir::ExprStruct(ref qpath, ref fields, ref base_expr) => {
- self.check_expr_struct(expr, qpath, fields, base_expr)
+ self.check_expr_struct(expr, expected, qpath, fields, base_expr)
}
hir::ExprField(ref base, ref field) => {
self.check_field(expr, lvalue_pref, &base, field)
diff --git a/src/test/run-pass/issue-31260.rs b/src/test/run-pass/issue-31260.rs
new file mode 100644
index 0000000000000..e771fc7464d00
--- /dev/null
+++ b/src/test/run-pass/issue-31260.rs
@@ -0,0 +1,20 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0