Merge #11771

11771: feat: Visualize compiler inserted reborrows via inlay hints r=Veykril a=Veykril

Disabled by default.

![image](https://user-images.githubusercontent.com/3757771/159165178-baaf968a-4381-468e-933f-5326ca1b203d.png)

Closes https://github.com/rust-analyzer/rust-analyzer/issues/11275


Co-authored-by: Lukas Wirth <lukastw97@gmail.com>

crates/rust-analyzer/src/config.rs

@@ -256,6 +256,8 @@ config_data! {
         inlayHints_chainingHints: bool                      = "true",
         /// Whether to show inlay type hints for return types of closures with blocks.
         inlayHints_closureReturnTypeHints: bool             = "false",
+        /// Whether to show inlay type hints for compiler inserted reborrows.
+        inlayHints_reborrowHints: bool                      = "false",
         /// Whether to show inlay type hints for elided lifetimes in function signatures.
         inlayHints_lifetimeElisionHints: LifetimeElisionDef = "\"never\"",
         /// Whether to prefer using parameter names as the name for elided lifetime hints if possible.
@@ -866,6 +868,7 @@ impl Config {
                 LifetimeElisionDef::SkipTrivial => LifetimeElisionHints::SkipTrivial,
             },
             hide_named_constructor_hints: self.data.inlayHints_hideNamedConstructorHints,
+            reborrow_hints: self.data.inlayHints_reborrowHints,
             param_names_for_lifetime_elision_hints: self
                 .data
                 .inlayHints_lifetimeElisionHints_useParameterNames,

crates/rust-analyzer/src/to_proto.rs

@@ -426,7 +426,11 @@ pub(crate) fn inlay_hint(
             _ => inlay_hint.label.to_string(),
         }),
         position: match inlay_hint.kind {
-            InlayKind::ParameterHint => position(line_index, inlay_hint.range.start()),
+            // before annotated thing
+            InlayKind::ParameterHint | InlayKind::ImplicitReborrow => {
+                position(line_index, inlay_hint.range.start())
+            }
+            // after annotated thing
             InlayKind::ClosureReturnTypeHint
             | InlayKind::TypeHint
             | InlayKind::ChainingHint
@@ -438,7 +442,9 @@ pub(crate) fn inlay_hint(
             InlayKind::ClosureReturnTypeHint | InlayKind::TypeHint | InlayKind::ChainingHint => {
                 Some(lsp_ext::InlayHintKind::TYPE)
             }
-            InlayKind::GenericParamListHint | InlayKind::LifetimeHint => None,
+            InlayKind::GenericParamListHint
+            | InlayKind::LifetimeHint
+            | InlayKind::ImplicitReborrow => None,
         },
         tooltip: None,
         padding_left: Some(match inlay_hint.kind {
@@ -447,6 +453,7 @@ pub(crate) fn inlay_hint(
             InlayKind::ChainingHint => true,
             InlayKind::GenericParamListHint => false,
             InlayKind::LifetimeHint => false,
+            InlayKind::ImplicitReborrow => false,
         }),
         padding_right: Some(match inlay_hint.kind {
             InlayKind::TypeHint | InlayKind::ChainingHint | InlayKind::ClosureReturnTypeHint => {
@@ -455,6 +462,7 @@ pub(crate) fn inlay_hint(
             InlayKind::ParameterHint => true,
             InlayKind::LifetimeHint => true,
             InlayKind::GenericParamListHint => false,
+            InlayKind::ImplicitReborrow => false,
         }),
     }
 }