9 files changed, 455 insertions, 409 deletions

diff --git a/crates/hir_expand/src/builtin_derive.rs b/crates/hir_expand/src/builtin_derive.rs
index 537c03028..b6a6d602f 100644
--- a/crates/hir_expand/src/builtin_derive.rs
+++ b/crates/hir_expand/src/builtin_derive.rs
@@ -269,7 +269,7 @@ mod tests {
     use expect_test::{expect, Expect};
     use name::AsName;
 
-    use crate::{test_db::TestDB, AstId, AttrId, MacroCallId, MacroCallKind, MacroCallLoc};
+    use crate::{test_db::TestDB, AstId, MacroCallId, MacroCallKind, MacroCallLoc};
 
     use super::*;
 
@@ -320,7 +320,7 @@ $0
             kind: MacroCallKind::Derive {
                 ast_id,
                 derive_name: name.to_string(),
-                derive_attr: AttrId(0),
+                derive_attr_index: 0,
             },
         };
 
diff --git a/crates/hir_expand/src/builtin_macro.rs b/crates/hir_expand/src/builtin_macro.rs
index 179de61f9..af9802144 100644
--- a/crates/hir_expand/src/builtin_macro.rs
+++ b/crates/hir_expand/src/builtin_macro.rs
@@ -578,6 +578,7 @@ mod tests {
                     krate,
                     kind: MacroCallKind::FnLike {
                         ast_id: AstId::new(file_id.into(), ast_id_map.ast_id(&macro_call)),
+                        fragment: FragmentKind::Expr,
                     },
                 };
 
@@ -788,9 +789,9 @@ mod tests {
             r##"
             #[rustc_builtin_macro]
             macro_rules! concat {}
-            concat!("foo", "r", 0, r#"bar"#, false);
+            concat!("foo", "r", 0, r#"bar"#, "\n", false);
             "##,
-            expect![[r#""foor0barfalse""#]],
+            expect![[r#""foor0bar\nfalse""#]],
         );
     }
 }
diff --git a/crates/hir_expand/src/db.rs b/crates/hir_expand/src/db.rs
index 1e4b0cc19..9fa419fcf 100644
--- a/crates/hir_expand/src/db.rs
+++ b/crates/hir_expand/src/db.rs
@@ -3,20 +3,18 @@
 use std::sync::Arc;
 
 use base_db::{salsa, SourceDatabase};
-use mbe::{ExpandError, ExpandResult, MacroDef, MacroRules};
+use mbe::{ExpandError, ExpandResult};
 use parser::FragmentKind;
 use syntax::{
     algo::diff,
-    ast::{MacroStmts, NameOwner},
-    AstNode, GreenNode, Parse,
-    SyntaxKind::*,
-    SyntaxNode,
+    ast::{self, NameOwner},
+    AstNode, GreenNode, Parse, SyntaxNode, SyntaxToken,
 };
 
 use crate::{
-    ast_id_map::AstIdMap, hygiene::HygieneFrame, BuiltinDeriveExpander, BuiltinFnLikeExpander,
-    EagerCallLoc, EagerMacroId, HirFileId, HirFileIdRepr, LazyMacroId, MacroCallId, MacroCallLoc,
-    MacroDefId, MacroDefKind, MacroFile, ProcMacroExpander,
+    ast_id_map::AstIdMap, hygiene::HygieneFrame, input::process_macro_input, BuiltinDeriveExpander,
+    BuiltinFnLikeExpander, EagerCallLoc, EagerMacroId, HirFileId, HirFileIdRepr, LazyMacroId,
+    MacroCallId, MacroCallLoc, MacroDefId, MacroDefKind, MacroFile, ProcMacroExpander,
 };
 
 /// Total limit on the number of tokens produced by any macro invocation.
@@ -27,23 +25,28 @@ const TOKEN_LIMIT: usize = 524288;
 
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub enum TokenExpander {
-    MacroRules(mbe::MacroRules),
-    MacroDef(mbe::MacroDef),
+    /// Old-style `macro_rules`.
+    MacroRules { mac: mbe::MacroRules, def_site_token_map: mbe::TokenMap },
+    /// AKA macros 2.0.
+    MacroDef { mac: mbe::MacroDef, def_site_token_map: mbe::TokenMap },
+    /// Stuff like `line!` and `file!`.
     Builtin(BuiltinFnLikeExpander),
+    /// `derive(Copy)` and such.
     BuiltinDerive(BuiltinDeriveExpander),
+    /// The thing we love the most here in rust-analyzer -- procedural macros.
     ProcMacro(ProcMacroExpander),
 }
 
 impl TokenExpander {
-    pub fn expand(
+    fn expand(
         &self,
         db: &dyn AstDatabase,
         id: LazyMacroId,
         tt: &tt::Subtree,
     ) -> mbe::ExpandResult<tt::Subtree> {
         match self {
-            TokenExpander::MacroRules(it) => it.expand(tt),
-            TokenExpander::MacroDef(it) => it.expand(tt),
+            TokenExpander::MacroRules { mac, .. } => mac.expand(tt),
+            TokenExpander::MacroDef { mac, .. } => mac.expand(tt),
             TokenExpander::Builtin(it) => it.expand(db, id, tt),
             // FIXME switch these to ExpandResult as well
             TokenExpander::BuiltinDerive(it) => it.expand(db, id, tt).into(),
@@ -56,23 +59,23 @@ impl TokenExpander {
         }
     }
 
-    pub fn map_id_down(&self, id: tt::TokenId) -> tt::TokenId {
+    pub(crate) fn map_id_down(&self, id: tt::TokenId) -> tt::TokenId {
         match self {
-            TokenExpander::MacroRules(it) => it.map_id_down(id),
-            TokenExpander::MacroDef(it) => it.map_id_down(id),
-            TokenExpander::Builtin(..) => id,
-            TokenExpander::BuiltinDerive(..) => id,
-            TokenExpander::ProcMacro(..) => id,
+            TokenExpander::MacroRules { mac, .. } => mac.map_id_down(id),
+            TokenExpander::MacroDef { mac, .. } => mac.map_id_down(id),
+            TokenExpander::Builtin(..)
+            | TokenExpander::BuiltinDerive(..)
+            | TokenExpander::ProcMacro(..) => id,
         }
     }
 
-    pub fn map_id_up(&self, id: tt::TokenId) -> (tt::TokenId, mbe::Origin) {
+    pub(crate) fn map_id_up(&self, id: tt::TokenId) -> (tt::TokenId, mbe::Origin) {
         match self {
-            TokenExpander::MacroRules(it) => it.map_id_up(id),
-            TokenExpander::MacroDef(it) => it.map_id_up(id),
-            TokenExpander::Builtin(..) => (id, mbe::Origin::Call),
-            TokenExpander::BuiltinDerive(..) => (id, mbe::Origin::Call),
-            TokenExpander::ProcMacro(..) => (id, mbe::Origin::Call),
+            TokenExpander::MacroRules { mac, .. } => mac.map_id_up(id),
+            TokenExpander::MacroDef { mac, .. } => mac.map_id_up(id),
+            TokenExpander::Builtin(..)
+            | TokenExpander::BuiltinDerive(..)
+            | TokenExpander::ProcMacro(..) => (id, mbe::Origin::Call),
         }
     }
 }
@@ -82,28 +85,48 @@ impl TokenExpander {
 pub trait AstDatabase: SourceDatabase {
     fn ast_id_map(&self, file_id: HirFileId) -> Arc<AstIdMap>;
 
+    /// Main public API -- parsis a hir file, not caring whether it's a real
+    /// file or a macro expansion.
     #[salsa::transparent]
     fn parse_or_expand(&self, file_id: HirFileId) -> Option<SyntaxNode>;
-
-    #[salsa::interned]
-    fn intern_macro(&self, macro_call: MacroCallLoc) -> LazyMacroId;
-    fn macro_arg_text(&self, id: MacroCallId) -> Option<GreenNode>;
-    #[salsa::transparent]
-    fn macro_arg(&self, id: MacroCallId) -> Option<Arc<(tt::Subtree, mbe::TokenMap)>>;
-    fn macro_def(&self, id: MacroDefId) -> Option<Arc<(TokenExpander, mbe::TokenMap)>>;
+    /// Implementation for the macro case.
     fn parse_macro_expansion(
         &self,
         macro_file: MacroFile,
     ) -> ExpandResult<Option<(Parse<SyntaxNode>, Arc<mbe::TokenMap>)>>;
-    fn macro_expand(&self, macro_call: MacroCallId) -> ExpandResult<Option<Arc<tt::Subtree>>>;
-
-    /// Firewall query that returns the error from the `macro_expand` query.
-    fn macro_expand_error(&self, macro_call: MacroCallId) -> Option<ExpandError>;
 
+    /// Macro ids. That's probably the tricksiest bit in rust-analyzer, and the
+    /// reason why we use salsa at all.
+    ///
+    /// We encode macro definitions into ids of macro calls, this what allows us
+    /// to be incremental.
+    #[salsa::interned]
+    fn intern_macro(&self, macro_call: MacroCallLoc) -> LazyMacroId;
+    /// Certain built-in macros are eager (`format!(concat!("file: ", file!(), "{}"")), 92`).
+    /// For them, we actually want to encode the whole token tree as an argument.
     #[salsa::interned]
     fn intern_eager_expansion(&self, eager: EagerCallLoc) -> EagerMacroId;
 
+    /// Lowers syntactic macro call to a token tree representation.
+    #[salsa::transparent]
+    fn macro_arg(&self, id: MacroCallId) -> Option<Arc<(tt::Subtree, mbe::TokenMap)>>;
+    /// Extracts syntax node, corresponding to a macro call. That's a firewall
+    /// query, only typing in the macro call itself changes the returned
+    /// subtree.
+    fn macro_arg_text(&self, id: MacroCallId) -> Option<GreenNode>;
+    /// Gets the expander for this macro. This compiles declarative macros, and
+    /// just fetches procedural ones.
+    fn macro_def(&self, id: MacroDefId) -> Option<Arc<TokenExpander>>;
+
+    /// Expand macro call to a token tree. This query is LRUed (we keep 128 or so results in memory)
+    fn macro_expand(&self, macro_call: MacroCallId) -> ExpandResult<Option<Arc<tt::Subtree>>>;
+    /// Special case of the previous query for procedural macros. We can't LRU
+    /// proc macros, since they are not deterministic in general, and
+    /// non-determinism breaks salsa in a very, very, very bad way. @edwin0cheng
+    /// heroically debugged this once!
     fn expand_proc_macro(&self, call: MacroCallId) -> Result<tt::Subtree, mbe::ExpandError>;
+    /// Firewall query that returns the error from the `macro_expand` query.
+    fn macro_expand_error(&self, macro_call: MacroCallId) -> Option<ExpandError>;
 
     fn hygiene_frame(&self, file_id: HirFileId) -> Arc<HygieneFrame>;
 }
@@ -115,36 +138,160 @@ pub trait AstDatabase: SourceDatabase {
 pub fn expand_hypothetical(
     db: &dyn AstDatabase,
     actual_macro_call: MacroCallId,
-    hypothetical_args: &syntax::ast::TokenTree,
-    token_to_map: syntax::SyntaxToken,
-) -> Option<(SyntaxNode, syntax::SyntaxToken)> {
-    let macro_file = MacroFile { macro_call_id: actual_macro_call };
+    hypothetical_args: &ast::TokenTree,
+    token_to_map: SyntaxToken,
+) -> Option<(SyntaxNode, SyntaxToken)> {
     let (tt, tmap_1) = mbe::syntax_node_to_token_tree(hypothetical_args.syntax());
     let range =
         token_to_map.text_range().checked_sub(hypothetical_args.syntax().text_range().start())?;
     let token_id = tmap_1.token_by_range(range)?;
-    let macro_def = expander(db, actual_macro_call)?;
+
+    let lazy_id = match actual_macro_call {
+        MacroCallId::LazyMacro(id) => id,
+        MacroCallId::EagerMacro(_) => return None,
+    };
+
+    let macro_def = {
+        let loc = db.lookup_intern_macro(lazy_id);
+        db.macro_def(loc.def)?
+    };
+
+    let hypothetical_expansion = macro_def.expand(db, lazy_id, &tt);
+
+    let fragment_kind = macro_fragment_kind(db, actual_macro_call);
+
     let (node, tmap_2) =
-        parse_macro_with_arg(db, macro_file, Some(std::sync::Arc::new((tt, tmap_1)))).value?;
-    let token_id = macro_def.0.map_id_down(token_id);
+        mbe::token_tree_to_syntax_node(&hypothetical_expansion.value, fragment_kind).ok()?;
+
+    let token_id = macro_def.map_id_down(token_id);
     let range = tmap_2.range_by_token(token_id)?.by_kind(token_to_map.kind())?;
     let token = node.syntax_node().covering_element(range).into_token()?;
     Some((node.syntax_node(), token))
 }
 
 fn ast_id_map(db: &dyn AstDatabase, file_id: HirFileId) -> Arc<AstIdMap> {
-    let map =
-        db.parse_or_expand(file_id).map_or_else(AstIdMap::default, |it| AstIdMap::from_source(&it));
+    let map = db.parse_or_expand(file_id).map(|it| AstIdMap::from_source(&it)).unwrap_or_default();
     Arc::new(map)
 }
 
-fn macro_def(db: &dyn AstDatabase, id: MacroDefId) -> Option<Arc<(TokenExpander, mbe::TokenMap)>> {
+fn parse_or_expand(db: &dyn AstDatabase, file_id: HirFileId) -> Option<SyntaxNode> {
+    match file_id.0 {
+        HirFileIdRepr::FileId(file_id) => Some(db.parse(file_id).tree().syntax().clone()),
+        HirFileIdRepr::MacroFile(macro_file) => {
+            db.parse_macro_expansion(macro_file).value.map(|(it, _)| it.syntax_node())
+        }
+    }
+}
+
+fn parse_macro_expansion(
+    db: &dyn AstDatabase,
+    macro_file: MacroFile,
+) -> ExpandResult<Option<(Parse<SyntaxNode>, Arc<mbe::TokenMap>)>> {
+    let _p = profile::span("parse_macro_expansion");
+    let result = db.macro_expand(macro_file.macro_call_id);
+
+    if let Some(err) = &result.err {
+        // Note:
+        // The final goal we would like to make all parse_macro success,
+        // such that the following log will not call anyway.
+        match macro_file.macro_call_id {
+            MacroCallId::LazyMacro(id) => {
+                let loc: MacroCallLoc = db.lookup_intern_macro(id);
+                let node = loc.kind.node(db);
+
+                // collect parent information for warning log
+                let parents = std::iter::successors(loc.kind.file_id().call_node(db), |it| {
+                    it.file_id.call_node(db)
+                })
+                .map(|n| format!("{:#}", n.value))
+                .collect::<Vec<_>>()
+                .join("\n");
+
+                log::warn!(
+                    "fail on macro_parse: (reason: {:?} macro_call: {:#}) parents: {}",
+                    err,
+                    node.value,
+                    parents
+                );
+            }
+            _ => {
+                log::warn!("fail on macro_parse: (reason: {:?})", err);
+            }
+        }
+    }
+    let tt = match result.value {
+        Some(tt) => tt,
+        None => return ExpandResult { value: None, err: result.err },
+    };
+
+    let fragment_kind = macro_fragment_kind(db, macro_file.macro_call_id);
+
+    log::debug!("expanded = {}", tt.as_debug_string());
+    log::debug!("kind = {:?}", fragment_kind);
+
+    let (parse, rev_token_map) = match mbe::token_tree_to_syntax_node(&tt, fragment_kind) {
+        Ok(it) => it,
+        Err(err) => {
+            log::debug!(
+                "failed to parse expanstion to {:?} = {}",
+                fragment_kind,
+                tt.as_debug_string()
+            );
+            return ExpandResult::only_err(err);
+        }
+    };
+
+    match result.err {
+        Some(err) => {
+            // Safety check for recursive identity macro.
+            let node = parse.syntax_node();
+            let file: HirFileId = macro_file.into();
+            let call_node = match file.call_node(db) {
+                Some(it) => it,
+                None => {
+                    return ExpandResult::only_err(err);
+                }
+            };
+            if is_self_replicating(&node, &call_node.value) {
+                return ExpandResult::only_err(err);
+            } else {
+                ExpandResult { value: Some((parse, Arc::new(rev_token_map))), err: Some(err) }
+            }
+        }
+        None => {
+            log::debug!("parse = {:?}", parse.syntax_node().kind());
+            ExpandResult { value: Some((parse, Arc::new(rev_token_map))), err: None }
+        }
+    }
+}
+
+fn macro_arg(db: &dyn AstDatabase, id: MacroCallId) -> Option<Arc<(tt::Subtree, mbe::TokenMap)>> {
+    let arg = db.macro_arg_text(id)?;
+    let (tt, tmap) = mbe::syntax_node_to_token_tree(&SyntaxNode::new_root(arg));
+    Some(Arc::new((tt, tmap)))
+}
+
+fn macro_arg_text(db: &dyn AstDatabase, id: MacroCallId) -> Option<GreenNode> {
+    let id = match id {
+        MacroCallId::LazyMacro(id) => id,
+        MacroCallId::EagerMacro(_id) => {
+            // FIXME: support macro_arg for eager macro
+            return None;
+        }
+    };
+    let loc = db.lookup_intern_macro(id);
+    let arg = loc.kind.arg(db)?;
+    let arg = process_macro_input(db, arg, id);
+    Some(arg.green().into())
+}
+
+fn macro_def(db: &dyn AstDatabase, id: MacroDefId) -> Option<Arc<TokenExpander>> {
     match id.kind {
         MacroDefKind::Declarative(ast_id) => match ast_id.to_node(db) {
-            syntax::ast::Macro::MacroRules(macro_rules) => {
+            ast::Macro::MacroRules(macro_rules) => {
                 let arg = macro_rules.token_tree()?;
-                let (tt, tmap) = mbe::ast_to_token_tree(&arg);
-                let rules = match MacroRules::parse(&tt) {
+                let (tt, def_site_token_map) = mbe::ast_to_token_tree(&arg);
+                let mac = match mbe::MacroRules::parse(&tt) {
                     Ok(it) => it,
                     Err(err) => {
                         let name = macro_rules.name().map(|n| n.to_string()).unwrap_or_default();
@@ -152,12 +299,12 @@ fn macro_def(db: &dyn AstDatabase, id: MacroDefId) -> Option<Arc<(TokenExpander,
                         return None;
                     }
                 };
-                Some(Arc::new((TokenExpander::MacroRules(rules), tmap)))
+                Some(Arc::new(TokenExpander::MacroRules { mac, def_site_token_map }))
             }
-            syntax::ast::Macro::MacroDef(macro_def) => {
+            ast::Macro::MacroDef(macro_def) => {
                 let arg = macro_def.body()?;
-                let (tt, tmap) = mbe::ast_to_token_tree(&arg);
-                let rules = match MacroDef::parse(&tt) {
+                let (tt, def_site_token_map) = mbe::ast_to_token_tree(&arg);
+                let mac = match mbe::MacroDef::parse(&tt) {
                     Ok(it) => it,
                     Err(err) => {
                         let name = macro_def.name().map(|n| n.to_string()).unwrap_or_default();
@@ -165,41 +312,18 @@ fn macro_def(db: &dyn AstDatabase, id: MacroDefId) -> Option<Arc<(TokenExpander,
                         return None;
                     }
                 };
-                Some(Arc::new((TokenExpander::MacroDef(rules), tmap)))
+                Some(Arc::new(TokenExpander::MacroDef { mac, def_site_token_map }))
             }
         },
-        MacroDefKind::BuiltIn(expander, _) => {
-            Some(Arc::new((TokenExpander::Builtin(expander), mbe::TokenMap::default())))
-        }
+        MacroDefKind::BuiltIn(expander, _) => Some(Arc::new(TokenExpander::Builtin(expander))),
         MacroDefKind::BuiltInDerive(expander, _) => {
-            Some(Arc::new((TokenExpander::BuiltinDerive(expander), mbe::TokenMap::default())))
+            Some(Arc::new(TokenExpander::BuiltinDerive(expander)))
         }
         MacroDefKind::BuiltInEager(..) => None,
-        MacroDefKind::ProcMacro(expander, ..) => {
-            Some(Arc::new((TokenExpander::ProcMacro(expander), mbe::TokenMap::default())))
-        }
+        MacroDefKind::ProcMacro(expander, ..) => Some(Arc::new(TokenExpander::ProcMacro(expander))),
     }
 }
 
-fn macro_arg_text(db: &dyn AstDatabase, id: MacroCallId) -> Option<GreenNode> {
-    let id = match id {
-        MacroCallId::LazyMacro(id) => id,
-        MacroCallId::EagerMacro(_id) => {
-            // FIXME: support macro_arg for eager macro
-            return None;
-        }
-    };
-    let loc = db.lookup_intern_macro(id);
-    let arg = loc.kind.arg(db)?;
-    Some(arg.green())
-}
-
-fn macro_arg(db: &dyn AstDatabase, id: MacroCallId) -> Option<Arc<(tt::Subtree, mbe::TokenMap)>> {
-    let arg = db.macro_arg_text(id)?;
-    let (tt, tmap) = mbe::syntax_node_to_token_tree(&SyntaxNode::new_root(arg));
-    Some(Arc::new((tt, tmap)))
-}
-
 fn macro_expand(db: &dyn AstDatabase, id: MacroCallId) -> ExpandResult<Option<Arc<tt::Subtree>>> {
     macro_expand_with_arg(db, id, None)
 }
@@ -208,19 +332,6 @@ fn macro_expand_error(db: &dyn AstDatabase, macro_call: MacroCallId) -> Option<E
     db.macro_expand(macro_call).err
 }
 
-fn expander(db: &dyn AstDatabase, id: MacroCallId) -> Option<Arc<(TokenExpander, mbe::TokenMap)>> {
-    let lazy_id = match id {
-        MacroCallId::LazyMacro(id) => id,
-        MacroCallId::EagerMacro(_id) => {
-            return None;
-        }
-    };
-
-    let loc = db.lookup_intern_macro(lazy_id);
-    let macro_rules = db.macro_def(loc.def)?;
-    Some(macro_rules)
-}
-
 fn macro_expand_with_arg(
     db: &dyn AstDatabase,
     id: MacroCallId,
@@ -254,7 +365,7 @@ fn macro_expand_with_arg(
         Some(it) => it,
         None => return ExpandResult::str_err("Fail to find macro definition".into()),
     };
-    let ExpandResult { value: tt, err } = macro_rules.0.expand(db, lazy_id, &macro_arg.0);
+    let ExpandResult { value: tt, err } = macro_rules.expand(db, lazy_id, &macro_arg.0);
     // Set a hard limit for the expanded tt
     let count = tt.count();
     if count > TOKEN_LIMIT {
@@ -294,116 +405,11 @@ fn expand_proc_macro(
     expander.expand(db, loc.krate, &macro_arg.0)
 }
 
-fn parse_or_expand(db: &dyn AstDatabase, file_id: HirFileId) -> Option<SyntaxNode> {
-    match file_id.0 {
-        HirFileIdRepr::FileId(file_id) => Some(db.parse(file_id).tree().syntax().clone()),
-        HirFileIdRepr::MacroFile(macro_file) => {
-            db.parse_macro_expansion(macro_file).value.map(|(it, _)| it.syntax_node())
-        }
-    }
-}
-
-fn parse_macro_expansion(
-    db: &dyn AstDatabase,
-    macro_file: MacroFile,
-) -> ExpandResult<Option<(Parse<SyntaxNode>, Arc<mbe::TokenMap>)>> {
-    parse_macro_with_arg(db, macro_file, None)
-}
-
-fn parse_macro_with_arg(
-    db: &dyn AstDatabase,
-    macro_file: MacroFile,
-    arg: Option<Arc<(tt::Subtree, mbe::TokenMap)>>,
-) -> ExpandResult<Option<(Parse<SyntaxNode>, Arc<mbe::TokenMap>)>> {
-    let macro_call_id = macro_file.macro_call_id;
-    let result = if let Some(arg) = arg {
-        macro_expand_with_arg(db, macro_call_id, Some(arg))
-    } else {
-        db.macro_expand(macro_call_id)
-    };
-
-    let _p = profile::span("parse_macro_expansion");
-
-    if let Some(err) = &result.err {
-        // Note:
-        // The final goal we would like to make all parse_macro success,
-        // such that the following log will not call anyway.
-        match macro_call_id {
-            MacroCallId::LazyMacro(id) => {
-                let loc: MacroCallLoc = db.lookup_intern_macro(id);
-                let node = loc.kind.node(db);
-
-                // collect parent information for warning log
-                let parents = std::iter::successors(loc.kind.file_id().call_node(db), |it| {
-                    it.file_id.call_node(db)
-                })
-                .map(|n| format!("{:#}", n.value))
-                .collect::<Vec<_>>()
-                .join("\n");
-
-                log::warn!(
-                    "fail on macro_parse: (reason: {:?} macro_call: {:#}) parents: {}",
-                    err,
-                    node.value,
-                    parents
-                );
-            }
-            _ => {
-                log::warn!("fail on macro_parse: (reason: {:?})", err);
-            }
-        }
-    }
-    let tt = match result.value {
-        Some(tt) => tt,
-        None => return ExpandResult { value: None, err: result.err },
-    };
-
-    let fragment_kind = to_fragment_kind(db, macro_call_id);
-
-    log::debug!("expanded = {}", tt.as_debug_string());
-    log::debug!("kind = {:?}", fragment_kind);
-
-    let (parse, rev_token_map) = match mbe::token_tree_to_syntax_node(&tt, fragment_kind) {
-        Ok(it) => it,
-        Err(err) => {
-            log::debug!(
-                "failed to parse expanstion to {:?} = {}",
-                fragment_kind,
-                tt.as_debug_string()
-            );
-            return ExpandResult::only_err(err);
-        }
-    };
-
-    match result.err {
-        Some(err) => {
-            // Safety check for recursive identity macro.
-            let node = parse.syntax_node();
-            let file: HirFileId = macro_file.into();
-            let call_node = match file.call_node(db) {
-                Some(it) => it,
-                None => {
-                    return ExpandResult::only_err(err);
-                }
-            };
-            if is_self_replicating(&node, &call_node.value) {
-                return ExpandResult::only_err(err);
-            } else {
-                ExpandResult { value: Some((parse, Arc::new(rev_token_map))), err: Some(err) }
-            }
-        }
-        None => {
-            log::debug!("parse = {:?}", parse.syntax_node().kind());
-            ExpandResult { value: Some((parse, Arc::new(rev_token_map))), err: None }
-        }
-    }
-}
-
 fn is_self_replicating(from: &SyntaxNode, to: &SyntaxNode) -> bool {
     if diff(from, to).is_empty() {
         return true;
     }
-    if let Some(stmts) = MacroStmts::cast(from.clone()) {
+    if let Some(stmts) = ast::MacroStmts::cast(from.clone()) {
         if stmts.statements().any(|stmt| diff(stmt.syntax(), to).is_empty()) {
             return true;
         }
@@ -420,62 +426,15 @@ fn hygiene_frame(db: &dyn AstDatabase, file_id: HirFileId) -> Arc<HygieneFrame>
     Arc::new(HygieneFrame::new(db, file_id))
 }
 
-/// Given a `MacroCallId`, return what `FragmentKind` it belongs to.
-/// FIXME: Not completed
-fn to_fragment_kind(db: &dyn AstDatabase, id: MacroCallId) -> FragmentKind {
-    let lazy_id = match id {
-        MacroCallId::LazyMacro(id) => id,
-        MacroCallId::EagerMacro(id) => {
-            return db.lookup_intern_eager_expansion(id).fragment;
-        }
-    };
-    let syn = db.lookup_intern_macro(lazy_id).kind.node(db).value;
-
-    let parent = match syn.parent() {
-        Some(it) => it,
-        None => return FragmentKind::Statements,
-    };
-
-    match parent.kind() {
-        MACRO_ITEMS | SOURCE_FILE => FragmentKind::Items,
-        MACRO_STMTS => FragmentKind::Statements,
-        MACRO_PAT => FragmentKind::Pattern,
-        MACRO_TYPE => FragmentKind::Type,
-        ITEM_LIST => FragmentKind::Items,
-        LET_STMT => {
-            // FIXME: Handle LHS Pattern
-            FragmentKind::Expr
+fn macro_fragment_kind(db: &dyn AstDatabase, id: MacroCallId) -> FragmentKind {
+    match id {
+        MacroCallId::LazyMacro(id) => {
+            let loc: MacroCallLoc = db.lookup_intern_macro(id);
+            loc.kind.fragment_kind()
         }
-        EXPR_STMT => FragmentKind::Statements,
-        BLOCK_EXPR => FragmentKind::Statements,
-        ARG_LIST => FragmentKind::Expr,
-        TRY_EXPR => FragmentKind::Expr,
-        TUPLE_EXPR => FragmentKind::Expr,
-        PAREN_EXPR => FragmentKind::Expr,
-        ARRAY_EXPR => FragmentKind::Expr,
-        FOR_EXPR => FragmentKind::Expr,
-        PATH_EXPR => FragmentKind::Expr,
-        CLOSURE_EXPR => FragmentKind::Expr,
-        CONDITION => FragmentKind::Expr,
-        BREAK_EXPR => FragmentKind::Expr,
-        RETURN_EXPR => FragmentKind::Expr,
-        MATCH_EXPR => FragmentKind::Expr,
-        MATCH_ARM => FragmentKind::Expr,
-        MATCH_GUARD => FragmentKind::Expr,
-        RECORD_EXPR_FIELD => FragmentKind::Expr,
-        CALL_EXPR => FragmentKind::Expr,
-        INDEX_EXPR => FragmentKind::Expr,
-        METHOD_CALL_EXPR => FragmentKind::Expr,
-        FIELD_EXPR => FragmentKind::Expr,
-        AWAIT_EXPR => FragmentKind::Expr,
-        CAST_EXPR => FragmentKind::Expr,
-        REF_EXPR => FragmentKind::Expr,
-        PREFIX_EXPR => FragmentKind::Expr,
-        RANGE_EXPR => FragmentKind::Expr,
-        BIN_EXPR => FragmentKind::Expr,
-        _ => {
-            // Unknown , Just guess it is `Items`
-            FragmentKind::Items
+        MacroCallId::EagerMacro(id) => {
+            let loc: EagerCallLoc = db.lookup_intern_eager_expansion(id);
+            loc.fragment
         }
     }
 }
diff --git a/crates/hir_expand/src/eager.rs b/crates/hir_expand/src/eager.rs
index f12132f84..85491fe8b 100644
--- a/crates/hir_expand/src/eager.rs
+++ b/crates/hir_expand/src/eager.rs
@@ -175,8 +175,13 @@ fn lazy_expand(
 ) -> ExpandResult<Option<InFile<SyntaxNode>>> {
     let ast_id = db.ast_id_map(macro_call.file_id).ast_id(&macro_call.value);
 
+    let fragment = crate::to_fragment_kind(&macro_call.value);
     let id: MacroCallId = def
-        .as_lazy_macro(db, krate, MacroCallKind::FnLike { ast_id: macro_call.with_value(ast_id) })
+        .as_lazy_macro(
+            db,
+            krate,
+            MacroCallKind::FnLike { ast_id: macro_call.with_value(ast_id), fragment },
+        )
         .into();
 
     let err = db.macro_expand_error(id);
diff --git a/crates/hir_expand/src/hygiene.rs b/crates/hir_expand/src/hygiene.rs
index 779725629..aca69e35a 100644
--- a/crates/hir_expand/src/hygiene.rs
+++ b/crates/hir_expand/src/hygiene.rs
@@ -5,6 +5,7 @@
 use std::sync::Arc;
 
 use base_db::CrateId;
+use db::TokenExpander;
 use either::Either;
 use mbe::Origin;
 use parser::SyntaxKind;
@@ -31,10 +32,14 @@ impl Hygiene {
     }
 
     // FIXME: this should just return name
-    pub fn name_ref_to_name(&self, name_ref: ast::NameRef) -> Either<Name, CrateId> {
+    pub fn name_ref_to_name(
+        &self,
+        db: &dyn AstDatabase,
+        name_ref: ast::NameRef,
+    ) -> Either<Name, CrateId> {
         if let Some(frames) = &self.frames {
             if name_ref.text() == "$crate" {
-                if let Some(krate) = frames.root_crate(name_ref.syntax()) {
+                if let Some(krate) = frames.root_crate(db, name_ref.syntax()) {
                     return Either::Right(krate);
                 }
             }
@@ -43,15 +48,19 @@ impl Hygiene {
         Either::Left(name_ref.as_name())
     }
 
-    pub fn local_inner_macros(&self, path: ast::Path) -> Option<CrateId> {
+    pub fn local_inner_macros(&self, db: &dyn AstDatabase, path: ast::Path) -> Option<CrateId> {
         let mut token = path.syntax().first_token()?.text_range();
         let frames = self.frames.as_ref()?;
         let mut current = frames.0.clone();
 
         loop {
-            let (mapped, origin) = current.expansion.as_ref()?.map_ident_up(token)?;
+            let (mapped, origin) = current.expansion.as_ref()?.map_ident_up(db, token)?;
             if origin == Origin::Def {
-                return if current.local_inner { frames.root_crate(path.syntax()) } else { None };
+                return if current.local_inner {
+                    frames.root_crate(db, path.syntax())
+                } else {
+                    None
+                };
             }
             current = current.call_site.as_ref()?.clone();
             token = mapped.value;
@@ -81,13 +90,13 @@ impl HygieneFrames {
         HygieneFrames(Arc::new(HygieneFrame::new(db, file_id)))
     }
 
-    fn root_crate(&self, node: &SyntaxNode) -> Option<CrateId> {
+    fn root_crate(&self, db: &dyn AstDatabase, node: &SyntaxNode) -> Option<CrateId> {
         let mut token = node.first_token()?.text_range();
         let mut result = self.0.krate;
         let mut current = self.0.clone();
 
         while let Some((mapped, origin)) =
-            current.expansion.as_ref().and_then(|it| it.map_ident_up(token))
+            current.expansion.as_ref().and_then(|it| it.map_ident_up(db, token))
         {
             result = current.krate;
 
@@ -111,26 +120,41 @@ impl HygieneFrames {
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 struct HygieneInfo {
-    arg_start: InFile<TextSize>,
+    file: MacroFile,
     /// The `macro_rules!` arguments.
     def_start: Option<InFile<TextSize>>,
 
-    macro_def: Arc<(db::TokenExpander, mbe::TokenMap)>,
+    macro_def: Arc<TokenExpander>,
     macro_arg: Arc<(tt::Subtree, mbe::TokenMap)>,
     exp_map: Arc<mbe::TokenMap>,
 }
 
 impl HygieneInfo {
-    fn map_ident_up(&self, token: TextRange) -> Option<(InFile<TextRange>, Origin)> {
+    fn map_ident_up(
+        &self,
+        db: &dyn AstDatabase,
+        token: TextRange,
+    ) -> Option<(InFile<TextRange>, Origin)> {
         let token_id = self.exp_map.token_by_range(token)?;
 
-        let (token_id, origin) = self.macro_def.0.map_id_up(token_id);
+        let (token_id, origin) = self.macro_def.map_id_up(token_id);
         let (token_map, tt) = match origin {
-            mbe::Origin::Call => (&self.macro_arg.1, self.arg_start),
-            mbe::Origin::Def => (
-                &self.macro_def.1,
-                *self.def_start.as_ref().expect("`Origin::Def` used with non-`macro_rules!` macro"),
-            ),
+            mbe::Origin::Call => {
+                let call_id = match self.file.macro_call_id {
+                    MacroCallId::LazyMacro(lazy) => lazy,
+                    MacroCallId::EagerMacro(_) => unreachable!(),
+                };
+                let loc: MacroCallLoc = db.lookup_intern_macro(call_id);
+                let arg_start = loc.kind.arg(db)?.text_range().start();
+                (&self.macro_arg.1, InFile::new(loc.kind.file_id(), arg_start))
+            }
+            mbe::Origin::Def => match (&*self.macro_def, self.def_start) {
+                (TokenExpander::MacroDef { def_site_token_map, .. }, Some(tt))
+                | (TokenExpander::MacroRules { def_site_token_map, .. }, Some(tt)) => {
+                    (def_site_token_map, tt)
+                }
+                _ => panic!("`Origin::Def` used with non-`macro_rules!` macro"),
+            },
         };
 
         let range = token_map.range_by_token(token_id)?.by_kind(SyntaxKind::IDENT)?;
@@ -143,8 +167,6 @@ fn make_hygiene_info(
     macro_file: MacroFile,
     loc: &MacroCallLoc,
 ) -> Option<HygieneInfo> {
-    let arg_tt = loc.kind.arg(db)?;
-
     let def_offset = loc.def.ast_id().left().and_then(|id| {
         let def_tt = match id.to_node(db) {
             ast::Macro::MacroRules(mac) => mac.token_tree()?.syntax().text_range().start(),
@@ -157,13 +179,7 @@ fn make_hygiene_info(
     let (_, exp_map) = db.parse_macro_expansion(macro_file).value?;
     let macro_arg = db.macro_arg(macro_file.macro_call_id)?;
 
-    Some(HygieneInfo {
-        arg_start: InFile::new(loc.kind.file_id(), arg_tt.text_range().start()),
-        def_start: def_offset,
-        macro_arg,
-        macro_def,
-        exp_map,
-    })
+    Some(HygieneInfo { file: macro_file, def_start: def_offset, macro_arg, macro_def, exp_map })
 }
 
 impl HygieneFrame {
@@ -174,7 +190,8 @@ impl HygieneFrame {
                 MacroCallId::EagerMacro(_id) => (None, None, false),
                 MacroCallId::LazyMacro(id) => {
                     let loc = db.lookup_intern_macro(id);
-                    let info = make_hygiene_info(db, macro_file, &loc);
+                    let info = make_hygiene_info(db, macro_file, &loc)
+                        .map(|info| (loc.kind.file_id(), info));
                     match loc.def.kind {
                         MacroDefKind::Declarative(_) => {
                             (info, Some(loc.def.krate), loc.def.local_inner)
@@ -188,7 +205,7 @@ impl HygieneFrame {
             },
         };
 
-        let info = match info {
+        let (calling_file, info) = match info {
             None => {
                 return HygieneFrame {
                     expansion: None,
@@ -202,7 +219,7 @@ impl HygieneFrame {
         };
 
         let def_site = info.def_start.map(|it| db.hygiene_frame(it.file_id));
-        let call_site = Some(db.hygiene_frame(info.arg_start.file_id));
+        let call_site = Some(db.hygiene_frame(calling_file));
 
         HygieneFrame { expansion: Some(info), local_inner, krate, call_site, def_site }
     }
diff --git a/crates/hir_expand/src/input.rs b/crates/hir_expand/src/input.rs
new file mode 100644
index 000000000..112216859
--- /dev/null
+++ b/crates/hir_expand/src/input.rs
@@ -0,0 +1,94 @@
+//! Macro input conditioning.
+
+use syntax::{
+    ast::{self, AttrsOwner},
+    AstNode, SyntaxNode,
+};
+
+use crate::{
+    db::AstDatabase,
+    name::{name, AsName},
+    LazyMacroId, MacroCallKind, MacroCallLoc,
+};
+
+pub(crate) fn process_macro_input(
+    db: &dyn AstDatabase,
+    node: SyntaxNode,
+    id: LazyMacroId,
+) -> SyntaxNode {
+    let loc: MacroCallLoc = db.lookup_intern_macro(id);
+
+    match loc.kind {
+        MacroCallKind::FnLike { .. } => node,
+        MacroCallKind::Derive { derive_attr_index, .. } => {
+            let item = match ast::Item::cast(node.clone()) {
+                Some(item) => item,
+                None => return node,
+            };
+
+            remove_derives_up_to(item, derive_attr_index as usize).syntax().clone()
+        }
+    }
+}
+
+/// Removes `#[derive]` attributes from `item`, up to `attr_index`.
+fn remove_derives_up_to(item: ast::Item, attr_index: usize) -> ast::Item {
+    let item = item.clone_for_update();
+    for attr in item.attrs().take(attr_index + 1) {
+        if let Some(name) =
+            attr.path().and_then(|path| path.as_single_segment()).and_then(|seg| seg.name_ref())
+        {
+            if name.as_name() == name![derive] {
+                attr.syntax().detach();
+            }
+        }
+    }
+    item
+}
+
+#[cfg(test)]
+mod tests {
+    use base_db::fixture::WithFixture;
+    use base_db::SourceDatabase;
+    use expect_test::{expect, Expect};
+
+    use crate::test_db::TestDB;
+
+    use super::*;
+
+    fn test_remove_derives_up_to(attr: usize, ra_fixture: &str, expect: Expect) {
+        let (db, file_id) = TestDB::with_single_file(&ra_fixture);
+        let parsed = db.parse(file_id);
+
+        let mut items: Vec<_> =
+            parsed.syntax_node().descendants().filter_map(ast::Item::cast).collect();
+        assert_eq!(items.len(), 1);
+
+        let item = remove_derives_up_to(items.pop().unwrap(), attr);
+        expect.assert_eq(&item.to_string());
+    }
+
+    #[test]
+    fn remove_derive() {
+        test_remove_derives_up_to(
+            2,
+            r#"
+#[allow(unused)]
+#[derive(Copy)]
+#[derive(Hello)]
+#[derive(Clone)]
+struct A {
+    bar: u32
+}
+        "#,
+            expect![[r#"
+#[allow(unused)]
+
+
+#[derive(Clone)]
+struct A {
+    bar: u32
+}"#]],
+        );
+    }
+}
diff --git a/crates/hir_expand/src/lib.rs b/crates/hir_expand/src/lib.rs
index a0e6aec62..5df11856e 100644
--- a/crates/hir_expand/src/lib.rs
+++ b/crates/hir_expand/src/lib.rs
@@ -14,9 +14,12 @@ pub mod builtin_macro;
 pub mod proc_macro;
 pub mod quote;
 pub mod eager;
+mod input;
 
 use either::Either;
+
 pub use mbe::{ExpandError, ExpandResult};
+pub use parser::FragmentKind;
 
 use std::hash::Hash;
 use std::sync::Arc;
@@ -290,13 +293,21 @@ pub struct MacroCallLoc {
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum MacroCallKind {
-    FnLike { ast_id: AstId<ast::MacroCall> },
-    Derive { ast_id: AstId<ast::Item>, derive_name: String, derive_attr: AttrId },
+    FnLike {
+        ast_id: AstId<ast::MacroCall>,
+        fragment: FragmentKind,
+    },
+    Derive {
+        ast_id: AstId<ast::Item>,
+        derive_name: String,
+        /// Syntactical index of the invoking `#[derive]` attribute.
+        ///
+        /// Outer attributes are counted first, then inner attributes. This does not support
+        /// out-of-line modules, which may have attributes spread across 2 files!
+        derive_attr_index: u32,
+    },
 }
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct AttrId(pub u32);
-
 impl MacroCallKind {
     fn file_id(&self) -> HirFileId {
         match self {
@@ -324,6 +335,13 @@ impl MacroCallKind {
             MacroCallKind::Derive { ast_id, .. } => Some(ast_id.to_node(db).syntax().clone()),
         }
     }
+
+    fn fragment_kind(&self) -> FragmentKind {
+        match self {
+            MacroCallKind::FnLike { fragment, .. } => *fragment,
+            MacroCallKind::Derive { .. } => FragmentKind::Items,
+        }
+    }
 }
 
 impl MacroCallId {
@@ -351,13 +369,12 @@ pub struct ExpansionInfo {
     /// The `macro_rules!` arguments.
     def: Option<InFile<ast::TokenTree>>,
 
-    macro_def: Arc<(db::TokenExpander, mbe::TokenMap)>,
+    macro_def: Arc<db::TokenExpander>,
     macro_arg: Arc<(tt::Subtree, mbe::TokenMap)>,
     exp_map: Arc<mbe::TokenMap>,
 }
 
 pub use mbe::Origin;
-use parser::FragmentKind;
 
 impl ExpansionInfo {
     pub fn call_node(&self) -> Option<InFile<SyntaxNode>> {
@@ -368,7 +385,7 @@ impl ExpansionInfo {
         assert_eq!(token.file_id, self.arg.file_id);
         let range = token.value.text_range().checked_sub(self.arg.value.text_range().start())?;
         let token_id = self.macro_arg.1.token_by_range(range)?;
-        let token_id = self.macro_def.0.map_id_down(token_id);
+        let token_id = self.macro_def.map_id_down(token_id);
 
         let range = self.exp_map.range_by_token(token_id)?.by_kind(token.value.kind())?;
 
@@ -383,17 +400,16 @@ impl ExpansionInfo {
     ) -> Option<(InFile<SyntaxToken>, Origin)> {
         let token_id = self.exp_map.token_by_range(token.value.text_range())?;
 
-        let (token_id, origin) = self.macro_def.0.map_id_up(token_id);
+        let (token_id, origin) = self.macro_def.map_id_up(token_id);
         let (token_map, tt) = match origin {
             mbe::Origin::Call => (&self.macro_arg.1, self.arg.clone()),
-            mbe::Origin::Def => (
-                &self.macro_def.1,
-                self.def
-                    .as_ref()
-                    .expect("`Origin::Def` used with non-`macro_rules!` macro")
-                    .as_ref()
-                    .map(|tt| tt.syntax().clone()),
-            ),
+            mbe::Origin::Def => match (&*self.macro_def, self.def.as_ref()) {
+                (db::TokenExpander::MacroRules { def_site_token_map, .. }, Some(tt))
+                | (db::TokenExpander::MacroDef { def_site_token_map, .. }, Some(tt)) => {
+                    (def_site_token_map, tt.as_ref().map(|tt| tt.syntax().clone()))
+                }
+                _ => panic!("`Origin::Def` used with non-`macro_rules!` macro"),
+            },
         };
 
         let range = token_map.range_by_token(token_id)?.by_kind(token.value.kind())?;
@@ -563,3 +579,59 @@ impl<N: AstNode> InFile<N> {
         self.with_value(self.value.syntax())
     }
 }
+
+/// Given a `MacroCallId`, return what `FragmentKind` it belongs to.
+/// FIXME: Not completed
+pub fn to_fragment_kind(call: &ast::MacroCall) -> FragmentKind {
+    use syntax::SyntaxKind::*;
+
+    let syn = call.syntax();
+
+    let parent = match syn.parent() {
+        Some(it) => it,
+        None => return FragmentKind::Statements,
+    };
+
+    match parent.kind() {
+        MACRO_ITEMS | SOURCE_FILE => FragmentKind::Items,
+        MACRO_STMTS => FragmentKind::Statements,
+        MACRO_PAT => FragmentKind::Pattern,
+        MACRO_TYPE => FragmentKind::Type,
+        ITEM_LIST => FragmentKind::Items,
+        LET_STMT => {
+            // FIXME: Handle LHS Pattern
+            FragmentKind::Expr
+        }
+        EXPR_STMT => FragmentKind::Statements,
+        BLOCK_EXPR => FragmentKind::Statements,
+        ARG_LIST => FragmentKind::Expr,
+        TRY_EXPR => FragmentKind::Expr,
+        TUPLE_EXPR => FragmentKind::Expr,
+        PAREN_EXPR => FragmentKind::Expr,
+        ARRAY_EXPR => FragmentKind::Expr,
+        FOR_EXPR => FragmentKind::Expr,
+        PATH_EXPR => FragmentKind::Expr,
+        CLOSURE_EXPR => FragmentKind::Expr,
+        CONDITION => FragmentKind::Expr,
+        BREAK_EXPR => FragmentKind::Expr,
+        RETURN_EXPR => FragmentKind::Expr,
+        MATCH_EXPR => FragmentKind::Expr,
+        MATCH_ARM => FragmentKind::Expr,
+        MATCH_GUARD => FragmentKind::Expr,
+        RECORD_EXPR_FIELD => FragmentKind::Expr,
+        CALL_EXPR => FragmentKind::Expr,
+        INDEX_EXPR => FragmentKind::Expr,
+        METHOD_CALL_EXPR => FragmentKind::Expr,
+        FIELD_EXPR => FragmentKind::Expr,
+        AWAIT_EXPR => FragmentKind::Expr,
+        CAST_EXPR => FragmentKind::Expr,
+        REF_EXPR => FragmentKind::Expr,
+        PREFIX_EXPR => FragmentKind::Expr,
+        RANGE_EXPR => FragmentKind::Expr,
+        BIN_EXPR => FragmentKind::Expr,
+        _ => {
+            // Unknown , Just guess it is `Items`
+            FragmentKind::Items
+        }
+    }
+}
diff --git a/crates/hir_expand/src/proc_macro.rs b/crates/hir_expand/src/proc_macro.rs
index 75e950816..d5643393a 100644
--- a/crates/hir_expand/src/proc_macro.rs
+++ b/crates/hir_expand/src/proc_macro.rs
@@ -2,7 +2,6 @@
 
 use crate::db::AstDatabase;
 use base_db::{CrateId, ProcMacroId};
-use tt::buffer::{Cursor, TokenBuffer};
 
 #[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
 pub struct ProcMacroExpander {
@@ -44,9 +43,6 @@ impl ProcMacroExpander {
                     .clone()
                     .ok_or_else(|| err!("No derive macro found."))?;
 
-                let tt = remove_derive_attrs(tt)
-                    .ok_or_else(|| err!("Fail to remove derive for custom derive"))?;
-
                 // Proc macros have access to the environment variables of the invoking crate.
                 let env = &krate_graph[calling_crate].env;
 
@@ -56,101 +52,3 @@ impl ProcMacroExpander {
         }
     }
 }
-
-fn eat_punct(cursor: &mut Cursor, c: char) -> bool {
-    if let Some(tt::buffer::TokenTreeRef::Leaf(tt::Leaf::Punct(punct), _)) = cursor.token_tree() {
-        if punct.char == c {
-            *cursor = cursor.bump();
-            return true;
-        }
-    }
-    false
-}
-
-fn eat_subtree(cursor: &mut Cursor, kind: tt::DelimiterKind) -> bool {
-    if let Some(tt::buffer::TokenTreeRef::Subtree(subtree, _)) = cursor.token_tree() {
-        if Some(kind) == subtree.delimiter_kind() {
-            *cursor = cursor.bump_subtree();
-            return true;
-        }
-    }
-    false
-}
-
-fn eat_ident(cursor: &mut Cursor, t: &str) -> bool {
-    if let Some(tt::buffer::TokenTreeRef::Leaf(tt::Leaf::Ident(ident), _)) = cursor.token_tree() {
-        if t == ident.text.as_str() {
-            *cursor = cursor.bump();
-            return true;
-        }
-    }
-    false
-}
-
-fn remove_derive_attrs(tt: &tt::Subtree) -> Option<tt::Subtree> {
-    let buffer = TokenBuffer::from_tokens(&tt.token_trees);
-    let mut p = buffer.begin();
-    let mut result = tt::Subtree::default();
-
-    while !p.eof() {
-        let curr = p;
-
-        if eat_punct(&mut p, '#') {
-            eat_punct(&mut p, '!');
-            let parent = p;
-            if eat_subtree(&mut p, tt::DelimiterKind::Bracket) {
-                if eat_ident(&mut p, "derive") {
-                    p = parent.bump();
-                    continue;
-                }
-            }
-        }
-
-        result.token_trees.push(curr.token_tree()?.cloned());
-        p = curr.bump();
-    }
-
-    Some(result)
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use test_utils::assert_eq_text;
-
-    #[test]
-    fn test_remove_derive_attrs() {
-        let tt = mbe::parse_to_token_tree(
-            r#"
-    #[allow(unused)]
-    #[derive(Copy)]
-    #[derive(Hello)]
-    struct A {
-        bar: u32
-    }
-"#,
-        )
-        .unwrap()
-        .0;
-        let result = format!("{:#?}", remove_derive_attrs(&tt).unwrap());
-
-        assert_eq_text!(
-            r#"
-SUBTREE $
-  PUNCH   # [alone] 0
-  SUBTREE [] 1
-    IDENT   allow 2
-    SUBTREE () 3
-      IDENT   unused 4
-  IDENT   struct 15
-  IDENT   A 16
-  SUBTREE {} 17
-    IDENT   bar 18
-    PUNCH   : [alone] 19
-    IDENT   u32 20
-"#
-            .trim(),
-            &result
-        );
-    }
-}
diff --git a/crates/hir_expand/src/quote.rs b/crates/hir_expand/src/quote.rs
index c82487ef0..230a59964 100644
--- a/crates/hir_expand/src/quote.rs
+++ b/crates/hir_expand/src/quote.rs
@@ -196,8 +196,8 @@ impl_to_to_tokentrees! {
     tt::Literal => self { self };
     tt::Ident => self { self };
     tt::Punct => self { self };
-    &str => self { tt::Literal{text: format!("{:?}", self.escape_default().to_string()).into(), id: tt::TokenId::unspecified()}};
-    String => self { tt::Literal{text: format!("{:?}", self.escape_default().to_string()).into(), id: tt::TokenId::unspecified()}}
+    &str => self { tt::Literal{text: format!("\"{}\"", self.escape_debug()).into(), id: tt::TokenId::unspecified()}};
+    String => self { tt::Literal{text: format!("\"{}\"", self.escape_debug()).into(), id: tt::TokenId::unspecified()}}
 }
 
 #[cfg(test)]