Diagnose incorrect usages of the question mark operator

crates/hir/src/diagnostics.rs

@@ -6,7 +6,7 @@
 use base_db::CrateId;
 use cfg::{CfgExpr, CfgOptions};
 use either::Either;
-use hir_def::path::ModPath;
+use hir_def::{path::ModPath, TraitId};
 use hir_expand::{name::Name, HirFileId, InFile};
 use syntax::{ast, AstPtr, SyntaxNodePtr, TextRange};
 
@@ -33,6 +33,7 @@ diagnostics![
     BreakOutsideOfLoop,
     InactiveCode,
     IncorrectCase,
+    IncorrectTryExpr,
     InvalidDeriveTarget,
     MacroError,
     MalformedDerive,
@@ -40,6 +41,7 @@ diagnostics![
     MissingFields,
     MissingMatchArms,
     MissingUnsafe,
+    NotImplemented,
     NoSuchField,
     ReplaceFilterMapNextWithFindMap,
     TypeMismatch,
@@ -153,6 +155,16 @@ pub struct MismatchedArgCount {
     pub expected: usize,
     pub found: usize,
 }
+#[derive(Debug)]
+pub struct IncorrectTryExpr {
+    pub expr: InFile<AstPtr<ast::Expr>>,
+}
+#[derive(Debug)]
+pub struct NotImplemented {
+    pub expr: InFile<AstPtr<ast::Expr>>,
+    pub trait_: TraitId,
+    pub ty: Type,
+}
 
 #[derive(Debug)]
 pub struct MissingMatchArms {