3 files changed, 62 insertions, 19 deletions

diff --git a/crates/ra_hir_expand/src/builtin_macro.rs b/crates/ra_hir_expand/src/builtin_macro.rs
index b2c8a911f..9fc33e4b1 100644
--- a/crates/ra_hir_expand/src/builtin_macro.rs
+++ b/crates/ra_hir_expand/src/builtin_macro.rs
@@ -5,8 +5,9 @@ use crate::{
     name, AstId, CrateId, MacroDefId, MacroDefKind, TextUnit,
 };
 
-use crate::{quote, LazyMacroId};
+use crate::{quote, EagerMacroId, LazyMacroId, MacroCallId};
 use either::Either;
+use ra_db::{FileId, RelativePath};
 use ra_parser::FragmentKind;
 
 macro_rules! register_builtin {
@@ -38,12 +39,14 @@ macro_rules! register_builtin {
         impl EagerExpander {
             pub fn expand(
                 &self,
+                db: &dyn AstDatabase,
+                arg_id: EagerMacroId,
                 tt: &tt::Subtree,
             ) -> Result<(tt::Subtree, FragmentKind), mbe::ExpandError> {
                 let expander = match *self {
                     $( EagerExpander::$e_kind => $e_expand, )*
                 };
-                expander(tt)
+                expander(db,arg_id,tt)
             }
         }
 
@@ -80,7 +83,6 @@ pub fn find_builtin_macro(
 
 register_builtin! {
     LAZY:
-
     (column, Column) => column_expand,
     (compile_error, CompileError) => compile_error_expand,
     (file, File) => file_expand,
@@ -94,8 +96,8 @@ register_builtin! {
     (format_args_nl, FormatArgsNl) => format_args_expand,
 
     EAGER:
-    // eagers
-    (concat, Concat) => concat_expand
+    (concat, Concat) => concat_expand,
+    (include, Include) => include_expand
 }
 
 fn line_expand(
@@ -251,7 +253,11 @@ fn unquote_str(lit: &tt::Literal) -> Option<String> {
     token.value()
 }
 
-fn concat_expand(tt: &tt::Subtree) -> Result<(tt::Subtree, FragmentKind), mbe::ExpandError> {
+fn concat_expand(
+    _db: &dyn AstDatabase,
+    _arg_id: EagerMacroId,
+    tt: &tt::Subtree,
+) -> Result<(tt::Subtree, FragmentKind), mbe::ExpandError> {
     let mut text = String::new();
     for (i, t) in tt.token_trees.iter().enumerate() {
         match t {
@@ -266,6 +272,40 @@ fn concat_expand(tt: &tt::Subtree) -> Result<(tt::Subtree, FragmentKind), mbe::E
     Ok((quote!(#text), FragmentKind::Expr))
 }
 
+fn relative_file(db: &dyn AstDatabase, call_id: MacroCallId, path: &str) -> Option<FileId> {
+    let call_site = call_id.as_file().original_file(db);
+    let path = RelativePath::new(&path);
+
+    db.resolve_relative_path(call_site, &path)
+}
+
+fn include_expand(
+    db: &dyn AstDatabase,
+    arg_id: EagerMacroId,
+    tt: &tt::Subtree,
+) -> Result<(tt::Subtree, FragmentKind), mbe::ExpandError> {
+    let path = tt
+        .token_trees
+        .get(0)
+        .and_then(|tt| match tt {
+            tt::TokenTree::Leaf(tt::Leaf::Literal(it)) => unquote_str(&it),
+            _ => None,
+        })
+        .ok_or_else(|| mbe::ExpandError::ConversionError)?;
+
+    let file_id =
+        relative_file(db, arg_id.into(), &path).ok_or_else(|| mbe::ExpandError::ConversionError)?;
+
+    // FIXME:
+    // Handle include as expression
+    let node =
+        db.parse_or_expand(file_id.into()).ok_or_else(|| mbe::ExpandError::ConversionError)?;
+    let res =
+        mbe::syntax_node_to_token_tree(&node).ok_or_else(|| mbe::ExpandError::ConversionError)?.0;
+
+    Ok((res, FragmentKind::Items))
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
diff --git a/crates/ra_hir_expand/src/eager.rs b/crates/ra_hir_expand/src/eager.rs
index f95f37ede..2e6dd3dd8 100644
--- a/crates/ra_hir_expand/src/eager.rs
+++ b/crates/ra_hir_expand/src/eager.rs
@@ -42,24 +42,26 @@ pub fn expand_eager_macro(
     // When `lazy_expand` is called, its *parent* file must be already exists.
     // Here we store an eager macro id for the argument expanded subtree here
     // for that purpose.
-    let arg_id: MacroCallId = db
-        .intern_eager_expansion({
-            EagerCallLoc {
-                def,
-                fragment: FragmentKind::Expr,
-                subtree: Arc::new(parsed_args.clone()),
-                file_id: macro_call.file_id,
-            }
-        })
-        .into();
+    let arg_id = db.intern_eager_expansion({
+        EagerCallLoc {
+            def,
+            fragment: FragmentKind::Expr,
+            subtree: Arc::new(parsed_args.clone()),
+            file_id: macro_call.file_id,
+        }
+    });
+    let arg_file_id: MacroCallId = arg_id.into();
 
     let parsed_args = mbe::token_tree_to_syntax_node(&parsed_args, FragmentKind::Expr).ok()?.0;
-    let result =
-        eager_macro_recur(db, InFile::new(arg_id.as_file(), parsed_args.syntax_node()), resolver)?;
+    let result = eager_macro_recur(
+        db,
+        InFile::new(arg_file_id.as_file(), parsed_args.syntax_node()),
+        resolver,
+    )?;
     let subtree = to_subtree(&result)?;
 
     if let MacroDefKind::BuiltInEager(eager) = def.kind {
-        let (subtree, fragment) = eager.expand(&subtree).ok()?;
+        let (subtree, fragment) = eager.expand(db, arg_id, &subtree).ok()?;
         let eager =
             EagerCallLoc { def, fragment, subtree: Arc::new(subtree), file_id: macro_call.file_id };
 
diff --git a/crates/ra_hir_expand/src/name.rs b/crates/ra_hir_expand/src/name.rs
index 036cf7d1e..6d201256f 100644
--- a/crates/ra_hir_expand/src/name.rs
+++ b/crates/ra_hir_expand/src/name.rs
@@ -174,6 +174,7 @@ pub mod known {
         line,
         stringify,
         concat,
+        include,
         format_args,
         format_args_nl,
         env,