diff --git a/compiler/rustc_ast_pretty/src/pprust/state.rs b/compiler/rustc_ast_pretty/src/pprust/state.rs
index b80a553b4185c..ad8dbfd506d21 100644
--- a/compiler/rustc_ast_pretty/src/pprust/state.rs
+++ b/compiler/rustc_ast_pretty/src/pprust/state.rs
@@ -814,7 +814,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
}
fn bounds_to_string(&self, bounds: &[ast::GenericBound]) -> String {
- Self::to_string(|s| s.print_type_bounds("", bounds))
+ Self::to_string(|s| s.print_type_bounds(bounds))
}
fn pat_to_string(&self, pat: &ast::Pat) -> String {
@@ -991,7 +991,12 @@ impl<'a> State<'a> {
Term::Const(c) => self.print_expr_anon_const(c, &[]),
}
}
- ast::AssocConstraintKind::Bound { bounds } => self.print_type_bounds(":", &*bounds),
+ ast::AssocConstraintKind::Bound { bounds } => {
+ if !bounds.is_empty() {
+ self.word_nbsp(":");
+ self.print_type_bounds(&bounds);
+ }
+ }
}
}
@@ -1045,11 +1050,14 @@ impl<'a> State<'a> {
}
ast::TyKind::Path(Some(ref qself), ref path) => self.print_qpath(path, qself, false),
ast::TyKind::TraitObject(ref bounds, syntax) => {
- let prefix = if syntax == ast::TraitObjectSyntax::Dyn { "dyn" } else { "" };
- self.print_type_bounds(prefix, &bounds);
+ if syntax == ast::TraitObjectSyntax::Dyn {
+ self.word_nbsp("dyn");
+ }
+ self.print_type_bounds(bounds);
}
ast::TyKind::ImplTrait(_, ref bounds) => {
- self.print_type_bounds("impl", &bounds);
+ self.word_nbsp("impl");
+ self.print_type_bounds(bounds);
}
ast::TyKind::Array(ref ty, ref length) => {
self.word("[");
@@ -1549,29 +1557,24 @@ impl<'a> State<'a> {
}
}
- pub fn print_type_bounds(&mut self, prefix: &'static str, bounds: &[ast::GenericBound]) {
- if !bounds.is_empty() {
- self.word(prefix);
- let mut first = true;
- for bound in bounds {
- if !(first && prefix.is_empty()) {
- self.nbsp();
- }
- if first {
- first = false;
- } else {
- self.word_space("+");
- }
+ pub fn print_type_bounds(&mut self, bounds: &[ast::GenericBound]) {
+ let mut first = true;
+ for bound in bounds {
+ if first {
+ first = false;
+ } else {
+ self.nbsp();
+ self.word_space("+");
+ }
- match bound {
- GenericBound::Trait(tref, modifier) => {
- if modifier == &TraitBoundModifier::Maybe {
- self.word("?");
- }
- self.print_poly_trait_ref(tref);
+ match bound {
+ GenericBound::Trait(tref, modifier) => {
+ if modifier == &TraitBoundModifier::Maybe {
+ self.word("?");
}
- GenericBound::Outlives(lt) => self.print_lifetime(*lt),
+ self.print_poly_trait_ref(tref);
}
+ GenericBound::Outlives(lt) => self.print_lifetime(*lt),
}
}
}
@@ -1580,22 +1583,14 @@ impl<'a> State<'a> {
self.print_name(lifetime.ident.name)
}
- pub(crate) fn print_lifetime_bounds(
- &mut self,
- lifetime: ast::Lifetime,
- bounds: &ast::GenericBounds,
- ) {
- self.print_lifetime(lifetime);
- if !bounds.is_empty() {
- self.word(": ");
- for (i, bound) in bounds.iter().enumerate() {
- if i != 0 {
- self.word(" + ");
- }
- match bound {
- ast::GenericBound::Outlives(lt) => self.print_lifetime(*lt),
- _ => panic!(),
- }
+ pub(crate) fn print_lifetime_bounds(&mut self, bounds: &ast::GenericBounds) {
+ for (i, bound) in bounds.iter().enumerate() {
+ if i != 0 {
+ self.word(" + ");
+ }
+ match bound {
+ ast::GenericBound::Outlives(lt) => self.print_lifetime(*lt),
+ _ => panic!(),
}
}
}
@@ -1613,11 +1608,18 @@ impl<'a> State<'a> {
match param.kind {
ast::GenericParamKind::Lifetime => {
let lt = ast::Lifetime { id: param.id, ident: param.ident };
- s.print_lifetime_bounds(lt, ¶m.bounds)
+ s.print_lifetime(lt);
+ if !param.bounds.is_empty() {
+ s.word_nbsp(":");
+ s.print_lifetime_bounds(¶m.bounds)
+ }
}
ast::GenericParamKind::Type { ref default } => {
s.print_ident(param.ident);
- s.print_type_bounds(":", ¶m.bounds);
+ if !param.bounds.is_empty() {
+ s.word_nbsp(":");
+ s.print_type_bounds(¶m.bounds);
+ }
if let Some(ref default) = default {
s.space();
s.word_space("=");
@@ -1630,7 +1632,10 @@ impl<'a> State<'a> {
s.space();
s.word_space(":");
s.print_type(ty);
- s.print_type_bounds(":", ¶m.bounds);
+ if !param.bounds.is_empty() {
+ s.word_nbsp(":");
+ s.print_type_bounds(¶m.bounds);
+ }
if let Some(ref default) = default {
s.space();
s.word_space("=");
diff --git a/compiler/rustc_ast_pretty/src/pprust/state/item.rs b/compiler/rustc_ast_pretty/src/pprust/state/item.rs
index 67b539a7ad41b..f1caf22f3640f 100644
--- a/compiler/rustc_ast_pretty/src/pprust/state/item.rs
+++ b/compiler/rustc_ast_pretty/src/pprust/state/item.rs
@@ -114,7 +114,10 @@ impl<'a> State<'a> {
self.word_space("type");
self.print_ident(ident);
self.print_generic_params(&generics.params);
- self.print_type_bounds(":", bounds);
+ if !bounds.is_empty() {
+ self.word_nbsp(":");
+ self.print_type_bounds(bounds);
+ }
self.print_where_clause_parts(where_clauses.0.0, before_predicates);
if let Some(ty) = ty {
self.space();
@@ -320,7 +323,10 @@ impl<'a> State<'a> {
real_bounds.push(b.clone());
}
}
- self.print_type_bounds(":", &real_bounds);
+ if !real_bounds.is_empty() {
+ self.word_nbsp(":");
+ self.print_type_bounds(&real_bounds);
+ }
self.print_where_clause(&generics.where_clause);
self.word(" ");
self.bopen();
@@ -347,7 +353,10 @@ impl<'a> State<'a> {
}
}
self.nbsp();
- self.print_type_bounds("=", &real_bounds);
+ if !real_bounds.is_empty() {
+ self.word_nbsp("=");
+ self.print_type_bounds(&real_bounds);
+ }
self.print_where_clause(&generics.where_clause);
self.word(";");
self.end(); // end inner head-block
@@ -618,14 +627,23 @@ impl<'a> State<'a> {
}) => {
self.print_formal_generic_params(bound_generic_params);
self.print_type(bounded_ty);
- self.print_type_bounds(":", bounds);
+ self.word(":");
+ if !bounds.is_empty() {
+ self.nbsp();
+ self.print_type_bounds(bounds);
+ }
}
ast::WherePredicate::RegionPredicate(ast::WhereRegionPredicate {
lifetime,
bounds,
..
}) => {
- self.print_lifetime_bounds(*lifetime, bounds);
+ self.print_lifetime(*lifetime);
+ self.word(":");
+ if !bounds.is_empty() {
+ self.nbsp();
+ self.print_lifetime_bounds(bounds);
+ }
}
ast::WherePredicate::EqPredicate(ast::WhereEqPredicate { lhs_ty, rhs_ty, .. }) => {
self.print_type(lhs_ty);
diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index c56f70e853daa..ed671e05970be 100644
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -1355,7 +1355,10 @@ impl<'a> Parser<'a> {
s.print_mutability(mut_ty.mutbl, false);
s.popen();
s.print_type(&mut_ty.ty);
- s.print_type_bounds(" +", &bounds);
+ if !bounds.is_empty() {
+ s.word(" + ");
+ s.print_type_bounds(&bounds);
+ }
s.pclose()
});
diff --git a/src/test/pretty/where-clauses.rs b/src/test/pretty/where-clauses.rs
index 5614a81b0eb41..4183799457b7f 100644
--- a/src/test/pretty/where-clauses.rs
+++ b/src/test/pretty/where-clauses.rs
@@ -2,4 +2,7 @@
fn f<'a, 'b, T>(t: T) -> isize where T: 'a, 'a: 'b, T: Eq { 0 }
+// This is legal syntax, sometimes generated by macros. `where T: $($bound+)*`
+fn zero_bounds<'a, T>() where 'a:, T: {}
+
fn main() {}