Remove `TokenStream::flattened` and `InvisibleOrigin::FlattenToken`.

They are no longer needed.

This does slightly worsen the error message for a single test, but that
test contains code that is so badly broken that I'm not worried about
it.

2 files changed, 2 insertions, 50 deletions

diff --git a/compiler/rustc_ast/src/token.rs b/compiler/rustc_ast/src/token.rs
index 9d56cc83ac8..055481f5d87 100644
--- a/compiler/rustc_ast/src/token.rs
+++ b/compiler/rustc_ast/src/token.rs
@@ -30,10 +30,6 @@ pub enum InvisibleOrigin {
     // Converted from `proc_macro::Delimiter` in
     // `proc_macro::Delimiter::to_internal`, i.e. returned by a proc macro.
     ProcMacro,
-
-    // Converted from `TokenKind::NtLifetime` in `TokenStream::flatten_token`.
-    // Treated similarly to `ProcMacro`.
-    FlattenToken,
 }
 
 impl PartialEq for InvisibleOrigin {
@@ -130,9 +126,7 @@ impl Delimiter {
         match self {
             Delimiter::Parenthesis | Delimiter::Bracket | Delimiter::Brace => false,
             Delimiter::Invisible(InvisibleOrigin::MetaVar(_)) => false,
-            Delimiter::Invisible(InvisibleOrigin::FlattenToken | InvisibleOrigin::ProcMacro) => {
-                true
-            }
+            Delimiter::Invisible(InvisibleOrigin::ProcMacro) => true,
         }
     }
 
diff --git a/compiler/rustc_ast/src/tokenstream.rs b/compiler/rustc_ast/src/tokenstream.rs
index 8260842fb87..43d25d18075 100644
--- a/compiler/rustc_ast/src/tokenstream.rs
+++ b/compiler/rustc_ast/src/tokenstream.rs
@@ -25,7 +25,7 @@ use rustc_span::{DUMMY_SP, Span, SpanDecoder, SpanEncoder, Symbol, sym};
 
 use crate::ast::AttrStyle;
 use crate::ast_traits::{HasAttrs, HasTokens};
-use crate::token::{self, Delimiter, InvisibleOrigin, Token, TokenKind};
+use crate::token::{self, Delimiter, Token, TokenKind};
 use crate::{AttrVec, Attribute};
 
 /// Part of a `TokenStream`.
@@ -471,48 +471,6 @@ impl TokenStream {
         TokenStream::new(tts)
     }
 
-    fn flatten_token(token: &Token, spacing: Spacing) -> TokenTree {
-        match token.kind {
-            token::NtIdent(ident, is_raw) => {
-                TokenTree::Token(Token::new(token::Ident(ident.name, is_raw), ident.span), spacing)
-            }
-            token::NtLifetime(ident, is_raw) => TokenTree::Delimited(
-                DelimSpan::from_single(token.span),
-                DelimSpacing::new(Spacing::JointHidden, spacing),
-                Delimiter::Invisible(InvisibleOrigin::FlattenToken),
-                TokenStream::token_alone(token::Lifetime(ident.name, is_raw), ident.span),
-            ),
-            _ => TokenTree::Token(*token, spacing),
-        }
-    }
-
-    fn flatten_token_tree(tree: &TokenTree) -> TokenTree {
-        match tree {
-            TokenTree::Token(token, spacing) => TokenStream::flatten_token(token, *spacing),
-            TokenTree::Delimited(span, spacing, delim, tts) => {
-                TokenTree::Delimited(*span, *spacing, *delim, tts.flattened())
-            }
-        }
-    }
-
-    #[must_use]
-    pub fn flattened(&self) -> TokenStream {
-        fn can_skip(stream: &TokenStream) -> bool {
-            stream.iter().all(|tree| match tree {
-                TokenTree::Token(token, _) => {
-                    !matches!(token.kind, token::NtIdent(..) | token::NtLifetime(..))
-                }
-                TokenTree::Delimited(.., inner) => can_skip(inner),
-            })
-        }
-
-        if can_skip(self) {
-            return self.clone();
-        }
-
-        self.iter().map(|tree| TokenStream::flatten_token_tree(tree)).collect()
-    }
-
     // If `vec` is not empty, try to glue `tt` onto its last token. The return
     // value indicates if gluing took place.
     fn try_glue_to_last(vec: &mut Vec<TokenTree>, tt: &TokenTree) -> bool {