Merge #1076

1076: Const body inference r=flodiebold a=Lapz

This is the second part of #887. I've added type inference on const bodies and introduced the DefWithBody containing Function, Const and Static. I want to add tests but im unsure on how I would go about testing that completions work.


Co-authored-by: Lenard Pratt <l3np27@gmail.com>

crates/ra_syntax/src/ast/generated.rs

@@ -513,7 +513,11 @@ impl ast::TypeParamsOwner for ConstDef {}
 impl ast::AttrsOwner for ConstDef {}
 impl ast::DocCommentsOwner for ConstDef {}
 impl ast::TypeAscriptionOwner for ConstDef {}
-impl ConstDef {}
+impl ConstDef {
+    pub fn body(&self) -> Option<&Expr> {
+        super::child_opt(self)
+    }
+}
 
 // ContinueExpr
 #[derive(Debug, PartialEq, Eq, Hash)]
@@ -3364,7 +3368,11 @@ impl ast::TypeParamsOwner for StaticDef {}
 impl ast::AttrsOwner for StaticDef {}
 impl ast::DocCommentsOwner for StaticDef {}
 impl ast::TypeAscriptionOwner for StaticDef {}
-impl StaticDef {}
+impl StaticDef {
+    pub fn body(&self) -> Option<&Expr> {
+        super::child_opt(self)
+    }
+}
 
 // Stmt
 #[derive(Debug, PartialEq, Eq, Hash)]

crates/ra_syntax/src/grammar.ron

@@ -315,6 +315,7 @@ Grammar(
                 "DocCommentsOwner",
                 "TypeAscriptionOwner",
             ],
+            options: [ ["body","Expr"]],
         ),
         "StaticDef": (
             traits: [
@@ -325,6 +326,7 @@ Grammar(
                 "DocCommentsOwner",
                 "TypeAscriptionOwner",
             ],
+            options: [ ["body","Expr"]],
         ),
         "TypeAliasDef": (
             traits: [