Implement bulitin line! macro

crates/ra_hir/src/ty/tests.rs

@@ -4810,3 +4810,22 @@ fn no_such_field_diagnostics() {
     "###
     );
 }
+
+#[test]
+fn infer_builtin_macros_line() {
+    assert_snapshot!(
+        infer(r#"
+#[rustc_builtin_macro]
+macro_rules! line {() => {}}
+
+fn main() {
+    let x = line!();
+}
+"#),
+        @r###"
+        ![0; 1) '6': i32
+        [64; 88) '{     ...!(); }': ()
+        [74; 75) 'x': i32        
+    "###
+    );
+}

crates/ra_hir_def/src/nameres/collector.rs

@@ -1,8 +1,9 @@
 //! FIXME: write short doc here
 
 use hir_expand::{
+    builtin_macro::find_builtin_macro,
     name::{self, AsName, Name},
-    HirFileId, MacroCallId, MacroCallLoc, MacroDefId, MacroFileKind,
+    HirFileId, MacroCallId, MacroCallLoc, MacroDefId, MacroDefKind, MacroFileKind,
 };
 use ra_cfg::CfgOptions;
 use ra_db::{CrateId, FileId};
@@ -688,10 +689,30 @@ where
     fn collect_macro(&mut self, mac: &raw::MacroData) {
         let ast_id = AstId::new(self.file_id, mac.ast_id);
 
+        // Case 0: builtin macros
+        if mac.builtin {
+            if let Some(name) = &mac.name {
+                let krate = self.def_collector.def_map.krate;
+                if let Some(macro_id) = find_builtin_macro(name, krate, ast_id) {
+                    self.def_collector.define_macro(
+                        self.module_id,
+                        name.clone(),
+                        macro_id,
+                        mac.export,
+                    );
+                    return;
+                }
+            }
+        }
+
         // Case 1: macro rules, define a macro in crate-global mutable scope
         if is_macro_rules(&mac.path) {
             if let Some(name) = &mac.name {
-                let macro_id = MacroDefId { ast_id, krate: self.def_collector.def_map.krate };
+                let macro_id = MacroDefId {
+                    ast_id,
+                    krate: self.def_collector.def_map.krate,
+                    kind: MacroDefKind::Declarative,
+                };
                 self.def_collector.define_macro(self.module_id, name.clone(), macro_id, mac.export);
             }
             return;

crates/ra_hir_def/src/nameres/raw.rs

@@ -200,6 +200,7 @@ pub(super) struct MacroData {
     pub(super) path: Path,
     pub(super) name: Option<Name>,
     pub(super) export: bool,
+    pub(super) builtin: bool,
 }
 
 struct RawItemsCollector {
@@ -367,7 +368,11 @@ impl RawItemsCollector {
         // FIXME: cfg_attr
         let export = m.attrs().filter_map(|x| x.simple_name()).any(|name| name == "macro_export");
 
-        let m = self.raw_items.macros.alloc(MacroData { ast_id, path, name, export });
+        // FIXME: cfg_attr
+        let builtin =
+            m.attrs().filter_map(|x| x.simple_name()).any(|name| name == "rustc_builtin_macro");
+
+        let m = self.raw_items.macros.alloc(MacroData { ast_id, path, name, export, builtin });
         self.push_item(current_module, attrs, RawItemKind::Macro(m));
     }
 

crates/ra_hir_expand/src/builtin_macro.rs

@@ -0,0 +1,80 @@
+//! Builtin macro
+use crate::db::AstDatabase;
+use crate::{
+    ast::{self, AstNode},
+    name, AstId, CrateId, HirFileId, MacroCallId, MacroDefId, MacroDefKind, MacroFileKind,
+    TextUnit,
+};
+
+use crate::quote;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum BuiltinExpander {
+    Line,
+}
+
+impl BuiltinExpander {
+    pub fn expand(
+        &self,
+        db: &dyn AstDatabase,
+        id: MacroCallId,
+        tt: &tt::Subtree,
+    ) -> Result<tt::Subtree, mbe::ExpandError> {
+        match self {
+            BuiltinExpander::Line => line_expand(db, id, tt),
+        }
+    }
+}
+
+pub fn find_builtin_macro(
+    ident: &name::Name,
+    krate: CrateId,
+    ast_id: AstId<ast::MacroCall>,
+) -> Option<MacroDefId> {
+    // FIXME: Better registering method
+    if ident == &name::LINE_MACRO {
+        Some(MacroDefId { krate, ast_id, kind: MacroDefKind::BuiltIn(BuiltinExpander::Line) })
+    } else {
+        None
+    }
+}
+
+fn to_line_number(db: &dyn AstDatabase, file: HirFileId, pos: TextUnit) -> usize {
+    // FIXME: Use expansion info
+    let file_id = file.original_file(db);
+    let text = db.file_text(file_id);
+    let mut line_num = 1;
+
+    // Count line end
+    for (i, c) in text.chars().enumerate() {
+        if i == pos.to_usize() {
+            break;
+        }
+        if c == '\n' {
+            line_num += 1;
+        }
+    }
+
+    line_num
+}
+
+fn line_expand(
+    db: &dyn AstDatabase,
+    id: MacroCallId,
+    _tt: &tt::Subtree,
+) -> Result<tt::Subtree, mbe::ExpandError> {
+    let loc = db.lookup_intern_macro(id);
+    let macro_call = loc.ast_id.to_node(db);
+
+    let arg = macro_call.token_tree().ok_or_else(|| mbe::ExpandError::UnexpectedToken)?;
+    let arg_start = arg.syntax().text_range().start();
+
+    let file = id.as_file(MacroFileKind::Expr);
+    let line_num = to_line_number(db, file, arg_start);
+
+    let expanded = quote! {
+        #line_num
+    };
+
+    Ok(expanded)
+}

crates/ra_hir_expand/src/db.rs

@@ -9,10 +9,37 @@ use ra_prof::profile;
 use ra_syntax::{AstNode, Parse, SyntaxNode};
 
 use crate::{
-    ast_id_map::AstIdMap, HirFileId, HirFileIdRepr, MacroCallId, MacroCallLoc, MacroDefId,
-    MacroFile, MacroFileKind,
+    ast_id_map::AstIdMap, BuiltinExpander, HirFileId, HirFileIdRepr, MacroCallId, MacroCallLoc,
+    MacroDefId, MacroDefKind, MacroFile, MacroFileKind,
 };
 
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub enum TokenExpander {
+    MacroRules(mbe::MacroRules),
+    Builtin(BuiltinExpander),
+}
+
+impl TokenExpander {
+    pub fn expand(
+        &self,
+        db: &dyn AstDatabase,
+        id: MacroCallId,
+        tt: &tt::Subtree,
+    ) -> Result<tt::Subtree, mbe::ExpandError> {
+        match self {
+            TokenExpander::MacroRules(it) => it.expand(tt),
+            TokenExpander::Builtin(it) => it.expand(db, id, tt),
+        }
+    }
+
+    pub fn shift(&self) -> u32 {
+        match self {
+            TokenExpander::MacroRules(it) => it.shift(),
+            TokenExpander::Builtin(_) => 0,
+        }
+    }
+}
+
 // FIXME: rename to ExpandDatabase
 #[salsa::query_group(AstDatabaseStorage)]
 pub trait AstDatabase: SourceDatabase {
@@ -24,7 +51,7 @@ pub trait AstDatabase: SourceDatabase {
     #[salsa::interned]
     fn intern_macro(&self, macro_call: MacroCallLoc) -> MacroCallId;
     fn macro_arg(&self, id: MacroCallId) -> Option<Arc<(tt::Subtree, mbe::TokenMap)>>;
-    fn macro_def(&self, id: MacroDefId) -> Option<Arc<(mbe::MacroRules, mbe::TokenMap)>>;
+    fn macro_def(&self, id: MacroDefId) -> Option<Arc<(TokenExpander, mbe::TokenMap)>>;
     fn parse_macro(
         &self,
         macro_file: MacroFile,
@@ -41,18 +68,25 @@ pub(crate) fn ast_id_map(db: &dyn AstDatabase, file_id: HirFileId) -> Arc<AstIdM
 pub(crate) fn macro_def(
     db: &dyn AstDatabase,
     id: MacroDefId,
-) -> Option<Arc<(mbe::MacroRules, mbe::TokenMap)>> {
-    let macro_call = id.ast_id.to_node(db);
-    let arg = macro_call.token_tree()?;
-    let (tt, tmap) = mbe::ast_to_token_tree(&arg).or_else(|| {
-        log::warn!("fail on macro_def to token tree: {:#?}", arg);
-        None
-    })?;
-    let rules = MacroRules::parse(&tt).ok().or_else(|| {
-        log::warn!("fail on macro_def parse: {:#?}", tt);
-        None
-    })?;
-    Some(Arc::new((rules, tmap)))
+) -> Option<Arc<(TokenExpander, mbe::TokenMap)>> {
+    match id.kind {
+        MacroDefKind::Declarative => {
+            let macro_call = id.ast_id.to_node(db);
+            let arg = macro_call.token_tree()?;
+            let (tt, tmap) = mbe::ast_to_token_tree(&arg).or_else(|| {
+                log::warn!("fail on macro_def to token tree: {:#?}", arg);
+                None
+            })?;
+            let rules = MacroRules::parse(&tt).ok().or_else(|| {
+                log::warn!("fail on macro_def parse: {:#?}", tt);
+                None
+            })?;
+            Some(Arc::new((TokenExpander::MacroRules(rules), tmap)))
+        }
+        MacroDefKind::BuiltIn(expander) => {
+            Some(Arc::new((TokenExpander::Builtin(expander.clone()), mbe::TokenMap::default())))
+        }
+    }
 }
 
 pub(crate) fn macro_arg(
@@ -74,7 +108,7 @@ pub(crate) fn macro_expand(
     let macro_arg = db.macro_arg(id).ok_or("Fail to args in to tt::TokenTree")?;
 
     let macro_rules = db.macro_def(loc.def).ok_or("Fail to find macro definition")?;
-    let tt = macro_rules.0.expand(&macro_arg.0).map_err(|err| format!("{:?}", err))?;
+    let tt = macro_rules.0.expand(db, id, &macro_arg.0).map_err(|err| format!("{:?}", err))?;
     // Set a hard limit for the expanded tt
     let count = tt.count();
     if count > 65536 {

crates/ra_hir_expand/src/hygiene.rs

@@ -9,7 +9,7 @@ use crate::{
     db::AstDatabase,
     either::Either,
     name::{AsName, Name},
-    HirFileId, HirFileIdRepr,
+    HirFileId, HirFileIdRepr, MacroDefKind,
 };
 
 #[derive(Debug)]
@@ -24,7 +24,10 @@ impl Hygiene {
             HirFileIdRepr::FileId(_) => None,
             HirFileIdRepr::MacroFile(macro_file) => {
                 let loc = db.lookup_intern_macro(macro_file.macro_call_id);
-                Some(loc.def.krate)
+                match loc.def.kind {
+                    MacroDefKind::Declarative => Some(loc.def.krate),
+                    MacroDefKind::BuiltIn(_) => None,
+                }
             }
         };
         Hygiene { def_crate }

crates/ra_hir_expand/src/lib.rs

@@ -10,6 +10,8 @@ pub mod either;
 pub mod name;
 pub mod hygiene;
 pub mod diagnostics;
+pub mod builtin_macro;
+pub mod quote;
 
 use std::hash::{Hash, Hasher};
 use std::sync::Arc;
@@ -21,6 +23,7 @@ use ra_syntax::{
 };
 
 use crate::ast_id_map::FileAstId;
+use crate::builtin_macro::BuiltinExpander;
 
 /// Input to the analyzer is a set of files, where each file is identified by
 /// `FileId` and contains source code. However, another source of source code in
@@ -122,6 +125,13 @@ impl salsa::InternKey for MacroCallId {
 pub struct MacroDefId {
     pub krate: CrateId,
     pub ast_id: AstId<ast::MacroCall>,
+    pub kind: MacroDefKind,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum MacroDefKind {
+    Declarative,
+    BuiltIn(BuiltinExpander),
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
@@ -144,7 +154,7 @@ pub struct ExpansionInfo {
     pub(crate) def_start: (HirFileId, TextUnit),
     pub(crate) shift: u32,
 
-    pub(crate) macro_def: Arc<(mbe::MacroRules, mbe::TokenMap)>,
+    pub(crate) macro_def: Arc<(db::TokenExpander, mbe::TokenMap)>,
     pub(crate) macro_arg: Arc<(tt::Subtree, mbe::TokenMap)>,
     pub(crate) exp_map: Arc<mbe::RevTokenMap>,
 }

crates/ra_hir_expand/src/name.rs

@@ -140,3 +140,6 @@ pub const RESULT_TYPE: Name = Name::new_inline_ascii(6, b"Result");
 pub const OUTPUT_TYPE: Name = Name::new_inline_ascii(6, b"Output");
 pub const TARGET_TYPE: Name = Name::new_inline_ascii(6, b"Target");
 pub const BOX_TYPE: Name = Name::new_inline_ascii(3, b"Box");
+
+// Builtin Macros
+pub const LINE_MACRO: Name = Name::new_inline_ascii(4, b"line");