Auto merge of rust-lang#12890 - Veykril:syntax-blocks, r=Veykril

internal: Assume condition/iterable is missing if there is only a BlockExpr

cc rust-lang/rust-analyzer#12880 (comment)

It sounds good on paper, so let's try it

Author: bors

crates/syntax/src/ast/generated/nodes.rs

@@ -880,7 +880,6 @@ impl ForExpr {
     pub fn for_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T![for]) }
     pub fn pat(&self) -> Option<Pat> { support::child(&self.syntax) }
     pub fn in_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T![in]) }
-    pub fn iterable(&self) -> Option<Expr> { support::child(&self.syntax) }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
@@ -890,7 +889,6 @@ pub struct IfExpr {
 impl ast::HasAttrs for IfExpr {}
 impl IfExpr {
     pub fn if_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T![if]) }
-    pub fn condition(&self) -> Option<Expr> { support::child(&self.syntax) }
     pub fn else_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T![else]) }
 }
 
@@ -1051,7 +1049,6 @@ pub struct WhileExpr {
 impl ast::HasAttrs for WhileExpr {}
 impl WhileExpr {
     pub fn while_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T![while]) }
-    pub fn condition(&self) -> Option<Expr> { support::child(&self.syntax) }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
@@ -1170,7 +1167,6 @@ pub struct MatchGuard {
 }
 impl MatchGuard {
     pub fn if_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T![if]) }
-    pub fn condition(&self) -> Option<Expr> { support::child(&self.syntax) }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]

crates/syntax/src/ast/node_ext.rs

@@ -806,6 +806,19 @@ impl ast::GenericParamList {
     }
 }
 
+impl ast::ForExpr {
+    pub fn iterable(&self) -> Option<ast::Expr> {
+        // If the iterable is a BlockExpr, check if the body is missing.
+        // If it is assume the iterable is the expression that is missing instead.
+        let mut exprs = support::children(self.syntax());
+        let first = exprs.next();
+        match first {
+            Some(ast::Expr::BlockExpr(_)) => exprs.next().and(first),
+            first => first,
+        }
+    }
+}
+
 impl ast::HasLoopBody for ast::ForExpr {
     fn loop_body(&self) -> Option<ast::BlockExpr> {
         let mut exprs = support::children(self.syntax());
@@ -815,6 +828,19 @@ impl ast::HasLoopBody for ast::ForExpr {
     }
 }
 
+impl ast::WhileExpr {
+    pub fn condition(&self) -> Option<ast::Expr> {
+        // If the condition is a BlockExpr, check if the body is missing.
+        // If it is assume the condition is the expression that is missing instead.
+        let mut exprs = support::children(self.syntax());
+        let first = exprs.next();
+        match first {
+            Some(ast::Expr::BlockExpr(_)) => exprs.next().and(first),
+            first => first,
+        }
+    }
+}
+
 impl ast::HasLoopBody for ast::WhileExpr {
     fn loop_body(&self) -> Option<ast::BlockExpr> {
         let mut exprs = support::children(self.syntax());
@@ -835,3 +861,15 @@ impl From<ast::Adt> for ast::Item {
         }
     }
 }
+
+impl ast::IfExpr {
+    pub fn condition(&self) -> Option<ast::Expr> {
+        support::child(&self.syntax)
+    }
+}
+
+impl ast::MatchGuard {
+    pub fn condition(&self) -> Option<ast::Expr> {
+        support::child(&self.syntax)
+    }
+}

crates/syntax/src/tests/sourcegen_ast.rs

@@ -682,6 +682,8 @@ fn lower_rule(acc: &mut Vec<Field>, grammar: &Grammar, label: Option<&String>, r
                     | "value"
                     | "trait"
                     | "self_ty"
+                    | "iterable"
+                    | "condition"
             );
             if manually_implemented {
                 return;