diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index 3aceec7002ab9..61b22ccc3bf5e 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -385,8 +385,8 @@ pub enum GenericParamKind {
     },
     Const {
         ty: P<Ty>,
-        /// Span of the `const` keyword.
-        kw_span: Span,
+        /// Span of the whole parameter definition, including default.
+        span: Span,
         /// Optional default value for the const generic param.
         default: Option<AnonConst>,
     },
@@ -410,10 +410,7 @@ impl GenericParam {
                 self.ident.span
             }
             GenericParamKind::Type { default: Some(ty) } => self.ident.span.to(ty.span),
-            GenericParamKind::Const { kw_span, default: Some(default), .. } => {
-                kw_span.to(default.value.span)
-            }
-            GenericParamKind::Const { kw_span, default: None, ty } => kw_span.to(ty.span),
+            GenericParamKind::Const { span, .. } => *span,
         }
     }
 }
diff --git a/compiler/rustc_ast/src/visit.rs b/compiler/rustc_ast/src/visit.rs
index 867ab7d947898..ad6fa4ac216df 100644
--- a/compiler/rustc_ast/src/visit.rs
+++ b/compiler/rustc_ast/src/visit.rs
@@ -1350,9 +1350,10 @@ macro_rules! common_visitor_and_walkers {
             match kind {
                 GenericParamKind::Lifetime => (),
                 GenericParamKind::Type { default } => visit_opt!(vis, visit_ty, default),
-                GenericParamKind::Const { ty, default, kw_span: _ } => {
+                GenericParamKind::Const { ty, default, span } => {
                     try_visit!(vis.visit_ty(ty));
                     visit_opt!(vis, visit_anon_const, default);
+                    try_visit!(visit_span(vis, span));
                 }
             }
             if let Some(sp) = colon_span {
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs
index d14e27982ef50..0706bdb119f01 100644
--- a/compiler/rustc_ast_lowering/src/lib.rs
+++ b/compiler/rustc_ast_lowering/src/lib.rs
@@ -1960,7 +1960,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
 
                 (hir::ParamName::Plain(self.lower_ident(param.ident)), kind)
             }
-            GenericParamKind::Const { ty, kw_span: _, default } => {
+            GenericParamKind::Const { ty, span: _, default } => {
                 let ty = self
                     .lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::GenericDefault));
 
diff --git a/compiler/rustc_ast_passes/src/ast_validation.rs b/compiler/rustc_ast_passes/src/ast_validation.rs
index da24825120376..53e2a1c695a8f 100644
--- a/compiler/rustc_ast_passes/src/ast_validation.rs
+++ b/compiler/rustc_ast_passes/src/ast_validation.rs
@@ -909,11 +909,11 @@ fn validate_generic_param_order(dcx: DiagCtxtHandle<'_>, generics: &[GenericPara
                 }
                 GenericParamKind::Type { default: None } => (),
                 GenericParamKind::Lifetime => (),
-                GenericParamKind::Const { ty: _, kw_span: _, default: Some(default) } => {
+                GenericParamKind::Const { ty: _, span: _, default: Some(default) } => {
                     ordered_params += " = ";
                     ordered_params += &pprust::expr_to_string(&default.value);
                 }
-                GenericParamKind::Const { ty: _, kw_span: _, default: None } => (),
+                GenericParamKind::Const { ty: _, span: _, default: None } => (),
             }
             first = false;
         }
diff --git a/compiler/rustc_builtin_macros/src/deriving/coerce_pointee.rs b/compiler/rustc_builtin_macros/src/deriving/coerce_pointee.rs
index 3a20b39798d7b..6082e376435a7 100644
--- a/compiler/rustc_builtin_macros/src/deriving/coerce_pointee.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/coerce_pointee.rs
@@ -124,7 +124,7 @@ pub(crate) fn expand_deriving_coerce_pointee(
                                 GenericParamKind::Type { default: _ } => {
                                     cx.typaram(p.span(), p.ident, p.bounds.clone(), None)
                                 }
-                                GenericParamKind::Const { ty, kw_span: _, default: _ } => cx
+                                GenericParamKind::Const { ty, span: _, default: _ } => cx
                                     .const_param(
                                         p.span(),
                                         p.ident,
diff --git a/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs b/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
index d642851bb77bf..d201ca196d694 100644
--- a/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
@@ -664,10 +664,10 @@ impl<'a> TraitDef<'a> {
 
                     cx.typaram(param.ident.span.with_ctxt(ctxt), param.ident, bounds, None)
                 }
-                GenericParamKind::Const { ty, kw_span, .. } => {
+                GenericParamKind::Const { ty, span, .. } => {
                     let const_nodefault_kind = GenericParamKind::Const {
                         ty: ty.clone(),
-                        kw_span: kw_span.with_ctxt(ctxt),
+                        span: span.with_ctxt(ctxt),
 
                         // We can't have default values inside impl block
                         default: None,
diff --git a/compiler/rustc_expand/src/build.rs b/compiler/rustc_expand/src/build.rs
index a333f2c7cb787..85683c1a03ff2 100644
--- a/compiler/rustc_expand/src/build.rs
+++ b/compiler/rustc_expand/src/build.rs
@@ -172,7 +172,7 @@ impl<'a> ExtCtxt<'a> {
             attrs: AttrVec::new(),
             bounds,
             is_placeholder: false,
-            kind: ast::GenericParamKind::Const { ty, kw_span: DUMMY_SP, default },
+            kind: ast::GenericParamKind::Const { ty, span: DUMMY_SP, default },
             colon_span: None,
         }
     }
diff --git a/compiler/rustc_parse/src/parser/generics.rs b/compiler/rustc_parse/src/parser/generics.rs
index af1d1a1ec6697..86326341a75ae 100644
--- a/compiler/rustc_parse/src/parser/generics.rs
+++ b/compiler/rustc_parse/src/parser/generics.rs
@@ -114,13 +114,18 @@ impl<'a> Parser<'a> {
 
         // Parse optional const generics default value.
         let default = if self.eat(exp!(Eq)) { Some(self.parse_const_arg()?) } else { None };
+        let span = if let Some(ref default) = default {
+            const_span.to(default.value.span)
+        } else {
+            const_span.to(ty.span)
+        };
 
         Ok(GenericParam {
             ident,
             id: ast::DUMMY_NODE_ID,
             attrs: preceding_attrs,
             bounds: Vec::new(),
-            kind: GenericParamKind::Const { ty, kw_span: const_span, default },
+            kind: GenericParamKind::Const { ty, span, default },
             is_placeholder: false,
             colon_span: None,
         })
@@ -137,6 +142,11 @@ impl<'a> Parser<'a> {
 
         // Parse optional const generics default value.
         let default = if self.eat(exp!(Eq)) { Some(self.parse_const_arg()?) } else { None };
+        let span = if let Some(ref default) = default {
+            mistyped_const_ident.span.to(default.value.span)
+        } else {
+            mistyped_const_ident.span.to(ty.span)
+        };
 
         self.dcx()
             .struct_span_err(
@@ -156,7 +166,7 @@ impl<'a> Parser<'a> {
             id: ast::DUMMY_NODE_ID,
             attrs: preceding_attrs,
             bounds: Vec::new(),
-            kind: GenericParamKind::Const { ty, kw_span: mistyped_const_ident.span, default },
+            kind: GenericParamKind::Const { ty, span, default },
             is_placeholder: false,
             colon_span: None,
         })
diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index ac7bdda41954e..4e8316bcd4338 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -1656,7 +1656,7 @@ impl<'a, 'ast, 'ra, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
                         forward_ty_ban_rib.bindings.swap_remove(i);
                         forward_ty_ban_rib_const_param_ty.bindings.swap_remove(i);
                     }
-                    GenericParamKind::Const { ref ty, kw_span: _, ref default } => {
+                    GenericParamKind::Const { ref ty, span: _, ref default } => {
                         // Const parameters can't have param bounds.
                         assert!(param.bounds.is_empty());
 
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index 6230b8cfbec7d..a4022691995e7 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -2940,7 +2940,7 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
                         let span = if let [.., bound] = &param.bounds[..] {
                             bound.span()
                         } else if let GenericParam {
-                            kind: GenericParamKind::Const { ty, kw_span: _, default  }, ..
+                            kind: GenericParamKind::Const { ty, span: _, default  }, ..
                         } = param {
                             default.as_ref().map(|def| def.value.span).unwrap_or(ty.span)
                         } else {
diff --git a/src/tools/clippy/clippy_utils/src/ast_utils/mod.rs b/src/tools/clippy/clippy_utils/src/ast_utils/mod.rs
index e65914b9b5ee5..e6396987cc6d9 100644
--- a/src/tools/clippy/clippy_utils/src/ast_utils/mod.rs
+++ b/src/tools/clippy/clippy_utils/src/ast_utils/mod.rs
@@ -886,13 +886,13 @@ pub fn eq_generic_param(l: &GenericParam, r: &GenericParam) -> bool {
             (
                 Const {
                     ty: lt,
-                    kw_span: _,
                     default: ld,
+                    span: _,
                 },
                 Const {
                     ty: rt,
-                    kw_span: _,
                     default: rd,
+                    span: _,
                 },
             ) => eq_ty(lt, rt) && both(ld.as_ref(), rd.as_ref(), eq_anon_const),
             _ => false,
diff --git a/src/tools/rustfmt/src/spanned.rs b/src/tools/rustfmt/src/spanned.rs
index 507647566d417..ac132999b62eb 100644
--- a/src/tools/rustfmt/src/spanned.rs
+++ b/src/tools/rustfmt/src/spanned.rs
@@ -122,7 +122,7 @@ impl Spanned for ast::GenericParam {
     fn span(&self) -> Span {
         let lo = match self.kind {
             _ if !self.attrs.is_empty() => self.attrs[0].span.lo(),
-            ast::GenericParamKind::Const { kw_span, .. } => kw_span.lo(),
+            ast::GenericParamKind::Const { span, .. } => span.lo(),
             _ => self.ident.span.lo(),
         };
         let hi = if self.bounds.is_empty() {
diff --git a/src/tools/rustfmt/src/types.rs b/src/tools/rustfmt/src/types.rs
index dd1515805e54b..c0df01edd6dee 100644
--- a/src/tools/rustfmt/src/types.rs
+++ b/src/tools/rustfmt/src/types.rs
@@ -689,7 +689,7 @@ impl Rewrite for ast::GenericParam {
 
         let param_start = if let ast::GenericParamKind::Const {
             ref ty,
-            kw_span,
+            span,
             default,
         } = &self.kind
         {
@@ -711,7 +711,7 @@ impl Rewrite for ast::GenericParam {
                     default.rewrite_result(context, Shape::legacy(budget, shape.indent))?;
                 param.push_str(&rewrite);
             }
-            kw_span.lo()
+            span.lo()
         } else {
             param.push_str(rewrite_ident(context, self.ident));
             self.ident.span.lo()