Merge #846

846: WIP: Enable parsing of attributes inside a match block r=matklad a=vipentti

We allow invalid inner attributes to be parsed, e.g. inner attributes that are
not directly after the opening brace of the match block.

Instead we run validation on `MatchArmList` to allow better reporting of errors.

This fixes #845 and works towards #759 



Co-authored-by: Ville Penttinen <[email protected]>

5 files changed, 51 insertions, 1 deletions

diff --git a/crates/ra_syntax/src/ast.rs b/crates/ra_syntax/src/ast.rs
index 22105d6c9..350f01f33 100644
--- a/crates/ra_syntax/src/ast.rs
+++ b/crates/ra_syntax/src/ast.rs
@@ -153,6 +153,20 @@ impl FnDef {
 }
 
 impl Attr {
+    pub fn is_inner(&self) -> bool {
+        let tt = match self.value() {
+            None => return false,
+            Some(tt) => tt,
+        };
+
+        let prev = match tt.syntax().prev_sibling() {
+            None => return false,
+            Some(prev) => prev,
+        };
+
+        prev.kind() == EXCL
+    }
+
     pub fn as_atom(&self) -> Option<SmolStr> {
         let tt = self.value()?;
         let (_bra, attr, _ket) = tt.syntax().children().collect_tuple()?;
diff --git a/crates/ra_syntax/src/ast/generated.rs b/crates/ra_syntax/src/ast/generated.rs
index dd91b5063..c7aaccc95 100644
--- a/crates/ra_syntax/src/ast/generated.rs
+++ b/crates/ra_syntax/src/ast/generated.rs
@@ -1946,6 +1946,7 @@ impl ToOwned for MatchArm {
 }
 
 
+impl ast::AttrsOwner for MatchArm {}
 impl MatchArm {
     pub fn pats(&self) -> impl Iterator<Item = &Pat> {
         super::children(self)
@@ -1986,6 +1987,7 @@ impl ToOwned for MatchArmList {
 }
 
 
+impl ast::AttrsOwner for MatchArmList {}
 impl MatchArmList {
     pub fn arms(&self) -> impl Iterator<Item = &MatchArm> {
         super::children(self)
diff --git a/crates/ra_syntax/src/grammar.ron b/crates/ra_syntax/src/grammar.ron
index 27a123681..193b563aa 100644
--- a/crates/ra_syntax/src/grammar.ron
+++ b/crates/ra_syntax/src/grammar.ron
@@ -413,13 +413,15 @@ Grammar(
         ),
         "MatchArmList": (
             collections: [ ["arms", "MatchArm"] ],
+            traits: [ "AttrsOwner" ]
         ),
         "MatchArm": (
             options: [
                 [ "guard", "MatchGuard" ],
                 "Expr",
             ],
-            collections: [ [ "pats", "Pat" ] ]
+            collections: [ [ "pats", "Pat" ] ],
+            traits: [ "AttrsOwner" ]
         ),
         "MatchGuard": (options: ["Expr"]),
         "StructLit": (options: ["Path", "NamedFieldList", ["spread", "Expr"]]),
diff --git a/crates/ra_syntax/src/grammar/expressions/atom.rs b/crates/ra_syntax/src/grammar/expressions/atom.rs
index 27ba87657..e74305b6a 100644
--- a/crates/ra_syntax/src/grammar/expressions/atom.rs
+++ b/crates/ra_syntax/src/grammar/expressions/atom.rs
@@ -313,11 +313,39 @@ pub(crate) fn match_arm_list(p: &mut Parser) {
     assert!(p.at(L_CURLY));
     let m = p.start();
     p.eat(L_CURLY);
+
+    // test match_arms_inner_attribute
+    // fn foo() {
+    //     match () {
+    //         #![doc("Inner attribute")]
+    //         #![doc("Can be")]
+    //         #![doc("Stacked")]
+    //         _ => (),
+    //     }
+    // }
+    attributes::inner_attributes(p);
+
     while !p.at(EOF) && !p.at(R_CURLY) {
         if p.at(L_CURLY) {
             error_block(p, "expected match arm");
             continue;
         }
+
+        // test match_arms_outer_attributes
+        // fn foo() {
+        //     match () {
+        //         #[cfg(feature = "some")]
+        //         _ => (),
+        //         #[cfg(feature = "other")]
+        //         _ => (),
+        //         #[cfg(feature = "many")]
+        //         #[cfg(feature = "attributes")]
+        //         #[cfg(feature = "before")]
+        //         _ => (),
+        //     }
+        // }
+        attributes::outer_attributes(p);
+
         // test match_arms_commas
         // fn foo() {
         //     match () {
diff --git a/crates/ra_syntax/src/syntax_node/syntax_error.rs b/crates/ra_syntax/src/syntax_node/syntax_error.rs
index 412cf82cc..4ff998090 100644
--- a/crates/ra_syntax/src/syntax_node/syntax_error.rs
+++ b/crates/ra_syntax/src/syntax_node/syntax_error.rs
@@ -92,6 +92,7 @@ pub enum SyntaxErrorKind {
     UnclosedString,
     InvalidSuffix,
     InvalidBlockAttr,
+    InvalidMatchInnerAttr,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
@@ -136,6 +137,9 @@ impl fmt::Display for SyntaxErrorKind {
             InvalidBlockAttr => {
                 write!(f, "A block in this position cannot accept inner attributes")
             }
+            InvalidMatchInnerAttr => {
+                write!(f, "Inner attributes are only allowed directly after the opening brace of the match expression")
+            }
             ParseError(msg) => write!(f, "{}", msg.0),
         }
     }