Account for `ty::Error` when suggesting `impl Trait` or `Box<dyn Trait>`

[rust.git] / src / libsyntax / print / pprust.rs

diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 11c8cb8ef750017b1137cbb7266f1871799c3ea1..f0ef33e2f622d0f96ee7e5807ebe07f80490d441 100644 (file)
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -1226,20 +1226,22 @@ fn print_associated_type(
                 self.head(visibility_qualified(&item.vis, "union"));
                 self.print_struct(struct_def, generics, item.ident, item.span, true);
             }
-            ast::ItemKind::Impl(
+            ast::ItemKind::Impl {
                 unsafety,
                 polarity,
                 defaultness,
+                constness,
                 ref generics,
-                ref opt_trait,
-                ref ty,
-                ref impl_items,
-            ) => {
+                ref of_trait,
+                ref self_ty,
+                ref items,
+            } => {
                 self.head("");
                 self.print_visibility(&item.vis);
                 self.print_defaultness(defaultness);
                 self.print_unsafety(unsafety);
                 self.word_nbsp("impl");
+                self.print_constness(constness);
 
                 if !generics.params.is_empty() {
                     self.print_generic_params(&generics.params);
@@ -1250,19 +1252,19 @@ fn print_associated_type(
                     self.s.word("!");
                 }
 
-                if let Some(ref t) = *opt_trait {
+                if let Some(ref t) = *of_trait {
                     self.print_trait_ref(t);
                     self.s.space();
                     self.word_space("for");
                 }
 
-                self.print_type(ty);
+                self.print_type(self_ty);
                 self.print_where_clause(&generics.where_clause);
 
                 self.s.space();
                 self.bopen();
                 self.print_inner_attributes(&item.attrs);
-                for impl_item in impl_items {
+                for impl_item in items {
                     self.print_assoc_item(impl_item);
                 }
                 self.bclose(item.span);
@@ -1643,7 +1645,7 @@ fn print_else(&mut self, els: Option<&ast::Expr>) {
                     self.print_expr_as_cond(i);
                     self.s.space();
                     self.print_block(then);
-                    self.print_else(e.as_ref().map(|e| &**e))
+                    self.print_else(e.as_deref())
                 }
                 // Final `else` block.
                 ast::ExprKind::Block(ref b, _) => {
@@ -1947,7 +1949,7 @@ fn print_expr_outer_attr_style(&mut self, expr: &ast::Expr, is_inline: bool) {
                 self.print_let(pat, scrutinee);
             }
             ast::ExprKind::If(ref test, ref blk, ref elseopt) => {
-                self.print_if(test, blk, elseopt.as_ref().map(|e| &**e));
+                self.print_if(test, blk, elseopt.as_deref())
             }
             ast::ExprKind::While(ref test, ref blk, opt_label) => {
                 if let Some(label) = opt_label {
@@ -2773,6 +2775,13 @@ pub fn print_mutability(&mut self, mutbl: ast::Mutability, print_const: bool) {
         }
     }
 
+    crate fn print_constness(&mut self, s: ast::Constness) {
+        match s {
+            ast::Constness::Const => self.word_nbsp("const"),
+            ast::Constness::NotConst => {}
+        }
+    }
+
     crate fn print_is_auto(&mut self, s: ast::IsAuto) {
         match s {
             ast::IsAuto::Yes => self.word_nbsp("auto"),