5 files changed, 33 insertions, 15 deletions

diff --git a/crates/hir_expand/src/builtin_macro.rs b/crates/hir_expand/src/builtin_macro.rs
index 4d52904b9..75ec4196b 100644
--- a/crates/hir_expand/src/builtin_macro.rs
+++ b/crates/hir_expand/src/builtin_macro.rs
@@ -1,10 +1,10 @@
 //! Builtin macro
 use crate::{
     db::AstDatabase, name, quote, AstId, CrateId, EagerMacroId, LazyMacroId, MacroCallId,
-    MacroDefId, MacroDefKind, TextSize,
+    MacroCallLoc, MacroDefId, MacroDefKind, TextSize,
 };
 
-use base_db::{AnchoredPath, FileId};
+use base_db::{AnchoredPath, Edition, FileId};
 use cfg::CfgExpr;
 use either::Either;
 use mbe::{parse_exprs_with_sep, parse_to_token_tree, ExpandResult};
@@ -111,6 +111,8 @@ register_builtin! {
     (llvm_asm, LlvmAsm) => asm_expand,
     (asm, Asm) => asm_expand,
     (cfg, Cfg) => cfg_expand,
+    (core_panic, CorePanic) => panic_expand,
+    (std_panic, StdPanic) => panic_expand,
 
     EAGER:
     (compile_error, CompileError) => compile_error_expand,
@@ -284,6 +286,25 @@ fn cfg_expand(
     ExpandResult::ok(expanded)
 }
 
+fn panic_expand(
+    db: &dyn AstDatabase,
+    id: LazyMacroId,
+    tt: &tt::Subtree,
+) -> ExpandResult<tt::Subtree> {
+    let loc: MacroCallLoc = db.lookup_intern_macro(id);
+    // Expand to a macro call `$crate::panic::panic_{edition}`
+    let krate = tt::Ident { text: "$crate".into(), id: tt::TokenId::unspecified() };
+    let mut call = if db.crate_graph()[loc.krate].edition == Edition::Edition2021 {
+        quote!(#krate::panic::panic_2021!)
+    } else {
+        quote!(#krate::panic::panic_2015!)
+    };
+
+    // Pass the original arguments
+    call.token_trees.push(tt::TokenTree::Subtree(tt.clone()));
+    ExpandResult::ok(call)
+}
+
 fn unquote_str(lit: &tt::Literal) -> Option<String> {
     let lit = ast::make::tokens::literal(&lit.to_string());
     let token = ast::String::cast(lit)?;
@@ -563,7 +584,7 @@ mod tests {
                 };
 
                 let args = macro_call.token_tree().unwrap();
-                let parsed_args = mbe::ast_to_token_tree(&args).unwrap().0;
+                let parsed_args = mbe::ast_to_token_tree(&args).0;
                 let call_id = AstId::new(file_id.into(), ast_id_map.ast_id(&macro_call));
 
                 let arg_id = db.intern_eager_expansion({
diff --git a/crates/hir_expand/src/db.rs b/crates/hir_expand/src/db.rs
index c0ab70b60..10fe60821 100644
--- a/crates/hir_expand/src/db.rs
+++ b/crates/hir_expand/src/db.rs
@@ -119,7 +119,7 @@ pub fn expand_hypothetical(
     token_to_map: syntax::SyntaxToken,
 ) -> Option<(SyntaxNode, syntax::SyntaxToken)> {
     let macro_file = MacroFile { macro_call_id: actual_macro_call };
-    let (tt, tmap_1) = mbe::syntax_node_to_token_tree(hypothetical_args.syntax()).unwrap();
+    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)?;
@@ -143,10 +143,7 @@ fn macro_def(db: &dyn AstDatabase, id: MacroDefId) -> Option<Arc<(TokenExpander,
         MacroDefKind::Declarative(ast_id) => match ast_id.to_node(db) {
             syntax::ast::Macro::MacroRules(macro_rules) => {
                 let arg = macro_rules.token_tree()?;
-                let (tt, tmap) = mbe::ast_to_token_tree(&arg).or_else(|| {
-                    log::warn!("fail on macro_rules to token tree: {:#?}", arg);
-                    None
-                })?;
+                let (tt, tmap) = mbe::ast_to_token_tree(&arg);
                 let rules = match MacroRules::parse(&tt) {
                     Ok(it) => it,
                     Err(err) => {
@@ -159,10 +156,7 @@ fn macro_def(db: &dyn AstDatabase, id: MacroDefId) -> Option<Arc<(TokenExpander,
             }
             syntax::ast::Macro::MacroDef(macro_def) => {
                 let arg = macro_def.body()?;
-                let (tt, tmap) = mbe::ast_to_token_tree(&arg).or_else(|| {
-                    log::warn!("fail on macro_def to token tree: {:#?}", arg);
-                    None
-                })?;
+                let (tt, tmap) = mbe::ast_to_token_tree(&arg);
                 let rules = match MacroDef::parse(&tt) {
                     Ok(it) => it,
                     Err(err) => {
@@ -202,7 +196,7 @@ fn macro_arg_text(db: &dyn AstDatabase, id: MacroCallId) -> Option<GreenNode> {
 
 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))?;
+    let (tt, tmap) = mbe::syntax_node_to_token_tree(&SyntaxNode::new_root(arg));
     Some(Arc::new((tt, tmap)))
 }
 
diff --git a/crates/hir_expand/src/eager.rs b/crates/hir_expand/src/eager.rs
index 9eedc8461..9705526fa 100644
--- a/crates/hir_expand/src/eager.rs
+++ b/crates/hir_expand/src/eager.rs
@@ -106,7 +106,7 @@ pub fn expand_eager_macro(
     mut diagnostic_sink: &mut dyn FnMut(mbe::ExpandError),
 ) -> Result<EagerMacroId, ErrorEmitted> {
     let parsed_args = diagnostic_sink.option_with(
-        || Some(mbe::ast_to_token_tree(&macro_call.value.token_tree()?)?.0),
+        || Some(mbe::ast_to_token_tree(&macro_call.value.token_tree()?).0),
         || err("malformed macro invocation"),
     )?;
 
@@ -161,7 +161,7 @@ pub fn expand_eager_macro(
 }
 
 fn to_subtree(node: &SyntaxNode) -> Option<tt::Subtree> {
-    let mut subtree = mbe::syntax_node_to_token_tree(node)?.0;
+    let mut subtree = mbe::syntax_node_to_token_tree(node).0;
     subtree.delimiter = None;
     Some(subtree)
 }
diff --git a/crates/hir_expand/src/name.rs b/crates/hir_expand/src/name.rs
index 203ebbe85..a0f8766b0 100644
--- a/crates/hir_expand/src/name.rs
+++ b/crates/hir_expand/src/name.rs
@@ -208,6 +208,8 @@ pub mod known {
         line,
         module_path,
         assert,
+        core_panic,
+        std_panic,
         stringify,
         concat,
         include,
diff --git a/crates/hir_expand/src/quote.rs b/crates/hir_expand/src/quote.rs
index 08bc5aa49..c82487ef0 100644
--- a/crates/hir_expand/src/quote.rs
+++ b/crates/hir_expand/src/quote.rs
@@ -104,6 +104,7 @@ macro_rules! __quote {
     ( . ) => {$crate::__quote!(@PUNCT '.')};
     ( < ) => {$crate::__quote!(@PUNCT '<')};
     ( > ) => {$crate::__quote!(@PUNCT '>')};
+    ( ! ) => {$crate::__quote!(@PUNCT '!')};
 
     ( $first:tt $($tail:tt)+ ) => {
         {