diff --git a/compiler/rustc_ast_pretty/src/pprust/state.rs b/compiler/rustc_ast_pretty/src/pprust/state.rs
index fa8567eac6090..d7767efa9841b 100644
--- a/compiler/rustc_ast_pretty/src/pprust/state.rs
+++ b/compiler/rustc_ast_pretty/src/pprust/state.rs
@@ -131,7 +131,7 @@ pub fn print_crate<'a>(
 
         // Currently, in Rust 2018 we don't have `extern crate std;` at the crate
         // root, so this is not needed, and actually breaks things.
-        if edition.rust_2015() {
+        if edition.is_rust_2015() {
             // `#![no_std]`
             let fake_attr = attr::mk_attr_word(g, ast::AttrStyle::Inner, sym::no_std, DUMMY_SP);
             s.print_attribute(&fake_attr);
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index 81fd084ccb38e..628e9d88cf1df 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -2247,7 +2247,7 @@ impl<'a> Parser<'a> {
         let ext = self.parse_extern(case);
 
         if let Async::Yes { span, .. } = asyncness {
-            if span.rust_2015() {
+            if span.is_rust_2015() {
                 self.sess.emit_err(AsyncFnIn2015 { span, help: HelpUseLatestEdition::new() });
             }
         }
diff --git a/compiler/rustc_parse/src/parser/ty.rs b/compiler/rustc_parse/src/parser/ty.rs
index 306cbcff149f7..18aa20cee421f 100644
--- a/compiler/rustc_parse/src/parser/ty.rs
+++ b/compiler/rustc_parse/src/parser/ty.rs
@@ -673,7 +673,7 @@ impl<'a> Parser<'a> {
     /// Is a `dyn B0 + ... + Bn` type allowed here?
     fn is_explicit_dyn_type(&mut self) -> bool {
         self.check_keyword(kw::Dyn)
-            && (!self.token.uninterpolated_span().rust_2015()
+            && (self.token.uninterpolated_span().rust_2018()
                 || self.look_ahead(1, |t| {
                     (t.can_begin_bound() || t.kind == TokenKind::BinOp(token::Star))
                         && !can_continue_type_after_non_fn_ident(t)
diff --git a/compiler/rustc_resolve/src/build_reduced_graph.rs b/compiler/rustc_resolve/src/build_reduced_graph.rs
index 84421dc1f6225..2fb62ce53ba6e 100644
--- a/compiler/rustc_resolve/src/build_reduced_graph.rs
+++ b/compiler/rustc_resolve/src/build_reduced_graph.rs
@@ -265,7 +265,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 let ident = path.segments.get(0).expect("empty path in visibility").ident;
                 let crate_root = if ident.is_path_segment_keyword() {
                     None
-                } else if ident.span.rust_2015() {
+                } else if ident.span.is_rust_2015() {
                     Some(Segment::from_ident(Ident::new(
                         kw::PathRoot,
                         path.span.shrink_to_lo().with_ctxt(ident.span.ctxt()),
@@ -435,10 +435,10 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
         // appears, so imports in braced groups can have roots prepended independently.
         let is_glob = matches!(use_tree.kind, ast::UseTreeKind::Glob);
         let crate_root = match prefix_iter.peek() {
-            Some(seg) if !seg.ident.is_path_segment_keyword() && seg.ident.span.rust_2015() => {
+            Some(seg) if !seg.ident.is_path_segment_keyword() && seg.ident.span.is_rust_2015() => {
                 Some(seg.ident.span.ctxt())
             }
-            None if is_glob && use_tree.span.rust_2015() => Some(use_tree.span.ctxt()),
+            None if is_glob && use_tree.span.is_rust_2015() => Some(use_tree.span.ctxt()),
             _ => None,
         }
         .map(|ctxt| {
diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index 3bf041cebcb88..a08ae0f184bb2 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -462,7 +462,9 @@ impl<'a> Resolver<'a> {
 
         let first_name = match path.get(0) {
             // In the 2018 edition this lint is a hard error, so nothing to do
-            Some(seg) if seg.ident.span.rust_2015() && self.session.rust_2015() => seg.ident.name,
+            Some(seg) if seg.ident.span.is_rust_2015() && self.session.is_rust_2015() => {
+                seg.ident.name
+            }
             _ => return,
         };
 
@@ -1717,7 +1719,7 @@ impl<'a> Resolver<'a> {
                         Applicability::MaybeIncorrect,
                     )),
                 )
-            } else if self.session.rust_2015() {
+            } else if self.session.is_rust_2015() {
                 (
                     format!("maybe a missing crate `{ident}`?"),
                     Some((
@@ -1996,7 +1998,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
         mut path: Vec<Segment>,
         parent_scope: &ParentScope<'b>,
     ) -> Option<(Vec<Segment>, Option<String>)> {
-        if path[1].ident.span.rust_2015() {
+        if path[1].ident.span.is_rust_2015() {
             return None;
         }
 
diff --git a/compiler/rustc_resolve/src/ident.rs b/compiler/rustc_resolve/src/ident.rs
index 1c985d43658ae..d03ccf256fad7 100644
--- a/compiler/rustc_resolve/src/ident.rs
+++ b/compiler/rustc_resolve/src/ident.rs
@@ -85,7 +85,7 @@ impl<'a> Resolver<'a> {
         // 4c. Standard library prelude (de-facto closed, controlled).
         // 6. Language prelude: builtin attributes (closed, controlled).
 
-        let rust_2015 = ctxt.edition().rust_2015();
+        let rust_2015 = ctxt.edition().is_rust_2015();
         let (ns, macro_kind, is_absolute_path) = match scope_set {
             ScopeSet::All(ns, _) => (ns, None, false),
             ScopeSet::AbsolutePath(ns) => (ns, None, true),
@@ -1397,7 +1397,8 @@ impl<'a> Resolver<'a> {
                         module = Some(ModuleOrUniformRoot::ExternPrelude);
                         continue;
                     }
-                    if name == kw::PathRoot && ident.span.rust_2015() && self.session.rust_2018() {
+                    if name == kw::PathRoot && ident.span.is_rust_2015() && self.session.rust_2018()
+                    {
                         // `::a::b` from 2015 macro on 2018 global edition
                         module = Some(ModuleOrUniformRoot::CrateRootAndExternPrelude);
                         continue;
diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index 83932c089b311..3ca10ac50baa6 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -2145,7 +2145,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         let segments = &use_tree.prefix.segments;
         if !segments.is_empty() {
             let ident = segments[0].ident;
-            if ident.is_path_segment_keyword() || ident.span.rust_2015() {
+            if ident.is_path_segment_keyword() || ident.span.is_rust_2015() {
                 return;
             }
 
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index 37beff37c1fb9..cee0a7f3c203d 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -1343,7 +1343,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                     "!",
                     Applicability::MaybeIncorrect,
                 );
-                if path_str == "try" && span.rust_2015() {
+                if path_str == "try" && span.is_rust_2015() {
                     err.note("if you want the `try` keyword, you need Rust 2018 or later");
                 }
             }
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index 746e0f169bcf3..dbd419c1406f8 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -919,8 +919,8 @@ impl Session {
     }
 
     /// Is this edition 2015?
-    pub fn rust_2015(&self) -> bool {
-        self.edition().rust_2015()
+    pub fn is_rust_2015(&self) -> bool {
+        self.edition().is_rust_2015()
     }
 
     /// Are we allowed to use features from the Rust 2018 edition?
diff --git a/compiler/rustc_span/src/edition.rs b/compiler/rustc_span/src/edition.rs
index e66ec07904341..f16db69aae232 100644
--- a/compiler/rustc_span/src/edition.rs
+++ b/compiler/rustc_span/src/edition.rs
@@ -77,7 +77,7 @@ impl Edition {
     }
 
     /// Is this edition 2015?
-    pub fn rust_2015(self) -> bool {
+    pub fn is_rust_2015(self) -> bool {
         self == Edition::Edition2015
     }
 
diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs
index 006102a5f2fcf..e095cf3fda20d 100644
--- a/compiler/rustc_span/src/lib.rs
+++ b/compiler/rustc_span/src/lib.rs
@@ -705,8 +705,8 @@ impl Span {
     }
 
     #[inline]
-    pub fn rust_2015(self) -> bool {
-        self.edition().rust_2015()
+    pub fn is_rust_2015(self) -> bool {
+        self.edition().is_rust_2015()
     }
 
     #[inline]