2 files changed, 101 insertions, 11 deletions

diff --git a/crates/hir_expand/src/builtin_macro.rs b/crates/hir_expand/src/builtin_macro.rs
index 44a5556b6..79b970850 100644
--- a/crates/hir_expand/src/builtin_macro.rs
+++ b/crates/hir_expand/src/builtin_macro.rs
@@ -287,23 +287,34 @@ fn concat_expand(
     _arg_id: EagerMacroId,
     tt: &tt::Subtree,
 ) -> ExpandResult<Option<(tt::Subtree, FragmentKind)>> {
+    let mut err = None;
     let mut text = String::new();
     for (i, t) in tt.token_trees.iter().enumerate() {
         match t {
             tt::TokenTree::Leaf(tt::Leaf::Literal(it)) if i % 2 == 0 => {
-                text += &match unquote_str(&it) {
-                    Some(s) => s,
-                    None => {
-                        return ExpandResult::only_err(mbe::ExpandError::ConversionError);
-                    }
-                };
+                // concat works with string and char literals, so remove any quotes.
+                // It also works with integer, float and boolean literals, so just use the rest
+                // as-is.
+
+                text += it
+                    .text
+                    .trim_start_matches(|c| match c {
+                        'r' | '#' | '\'' | '"' => true,
+                        _ => false,
+                    })
+                    .trim_end_matches(|c| match c {
+                        '#' | '\'' | '"' => true,
+                        _ => false,
+                    });
             }
             tt::TokenTree::Leaf(tt::Leaf::Punct(punct)) if i % 2 == 1 && punct.char == ',' => (),
-            _ => return ExpandResult::only_err(mbe::ExpandError::UnexpectedToken),
+            _ => {
+                err.get_or_insert(mbe::ExpandError::UnexpectedToken);
+            }
         }
     }
 
-    ExpandResult::ok(Some((quote!(#text), FragmentKind::Expr)))
+    ExpandResult { value: Some((quote!(#text), FragmentKind::Expr)), err }
 }
 
 fn relative_file(
@@ -686,4 +697,19 @@ mod tests {
 
         assert_eq!(expanded, r#"b"""#);
     }
+
+    #[test]
+    fn test_concat_expand() {
+        let expanded = expand_builtin_macro(
+            r##"
+            #[rustc_builtin_macro]
+            macro_rules! concat {}
+            concat!("foo", 0, r#"bar"#);
+            "##,
+        );
+
+        assert_eq!(expanded, r#""foo0bar""#);
+
+        // FIXME: `true`/`false` literals don't work.
+    }
 }
diff --git a/crates/hir_expand/src/lib.rs b/crates/hir_expand/src/lib.rs
index 2633fd8f7..1a9428514 100644
--- a/crates/hir_expand/src/lib.rs
+++ b/crates/hir_expand/src/lib.rs
@@ -20,11 +20,11 @@ pub use mbe::{ExpandError, ExpandResult};
 use std::hash::Hash;
 use std::sync::Arc;
 
-use base_db::{impl_intern_key, salsa, CrateId, FileId};
+use base_db::{impl_intern_key, salsa, CrateId, FileId, FileRange};
 use syntax::{
-    algo,
+    algo::{self, skip_trivia_token},
     ast::{self, AstNode},
-    SyntaxNode, SyntaxToken, TextSize,
+    Direction, SyntaxNode, SyntaxToken, TextRange, TextSize,
 };
 
 use crate::ast_id_map::FileAstId;
@@ -445,6 +445,70 @@ impl InFile<SyntaxNode> {
     }
 }
 
+impl<'a> InFile<&'a SyntaxNode> {
+    pub fn original_file_range(self, db: &dyn db::AstDatabase) -> FileRange {
+        if let Some(range) = original_range_opt(db, self) {
+            let original_file = range.file_id.original_file(db);
+            if range.file_id == original_file.into() {
+                return FileRange { file_id: original_file, range: range.value };
+            }
+
+            log::error!("Fail to mapping up more for {:?}", range);
+            return FileRange { file_id: range.file_id.original_file(db), range: range.value };
+        }
+
+        // Fall back to whole macro call.
+        let mut node = self.cloned();
+        while let Some(call_node) = node.file_id.call_node(db) {
+            node = call_node;
+        }
+
+        let orig_file = node.file_id.original_file(db);
+        assert_eq!(node.file_id, orig_file.into());
+        FileRange { file_id: orig_file, range: node.value.text_range() }
+    }
+}
+
+fn original_range_opt(
+    db: &dyn db::AstDatabase,
+    node: InFile<&SyntaxNode>,
+) -> Option<InFile<TextRange>> {
+    let expansion = node.file_id.expansion_info(db)?;
+
+    // the input node has only one token ?
+    let single = skip_trivia_token(node.value.first_token()?, Direction::Next)?
+        == skip_trivia_token(node.value.last_token()?, Direction::Prev)?;
+
+    Some(node.value.descendants().find_map(|it| {
+        let first = skip_trivia_token(it.first_token()?, Direction::Next)?;
+        let first = ascend_call_token(db, &expansion, node.with_value(first))?;
+
+        let last = skip_trivia_token(it.last_token()?, Direction::Prev)?;
+        let last = ascend_call_token(db, &expansion, node.with_value(last))?;
+
+        if (!single && first == last) || (first.file_id != last.file_id) {
+            return None;
+        }
+
+        Some(first.with_value(first.value.text_range().cover(last.value.text_range())))
+    })?)
+}
+
+fn ascend_call_token(
+    db: &dyn db::AstDatabase,
+    expansion: &ExpansionInfo,
+    token: InFile<SyntaxToken>,
+) -> Option<InFile<SyntaxToken>> {
+    let (mapped, origin) = expansion.map_token_up(token.as_ref())?;
+    if origin != Origin::Call {
+        return None;
+    }
+    if let Some(info) = mapped.file_id.expansion_info(db) {
+        return ascend_call_token(db, &info, mapped);
+    }
+    Some(mapped)
+}
+
 impl InFile<SyntaxToken> {
     pub fn ancestors_with_macros(
         self,