Merge #7068

7068: Add VSCode command to view the hir of a function body r=theotherphil a=theotherphil

Will fix https://github.com/rust-analyzer/rust-analyzer/issues/7061. Very rough initial version just to work out where I needed to wire everything up.

@matklad would you be happy merging a hir visualiser of some kind? If so, do you have any thoughts on what you'd like it show, and how?

I've spent very little time on this thus far, so I'm fine with throwing away the contents of this PR, but I want to avoid taking the time to make this more polished/interactive/useful only to discover that no-one else has any interest in this functionality.

![image](https://user-images.githubusercontent.com/1974256/103236081-bb58f700-493b-11eb-9d12-55ae1b870f8f.png)


Co-authored-by: Phil Ellison <[email protected]>

1 files changed, 14 insertions, 1 deletions

diff --git a/crates/hir/src/code_model.rs b/crates/hir/src/code_model.rs
index 3c83231cf..62eccf475 100644
--- a/crates/hir/src/code_model.rs
+++ b/crates/hir/src/code_model.rs
@@ -39,7 +39,7 @@ use hir_ty::{
     TyDefId, TyKind, TypeCtor,
 };
 use rustc_hash::FxHashSet;
-use stdx::impl_from;
+use stdx::{format_to, impl_from};
 use syntax::{
     ast::{self, AttrsOwner, NameOwner},
     AstNode, SmolStr,
@@ -797,6 +797,19 @@ impl Function {
     pub fn has_body(self, db: &dyn HirDatabase) -> bool {
         db.function_data(self.id).has_body
     }
+
+    /// A textual representation of the HIR of this function for debugging purposes.
+    pub fn debug_hir(self, db: &dyn HirDatabase) -> String {
+        let body = db.body(self.id.into());
+
+        let mut result = String::new();
+        format_to!(result, "HIR expressions in the body of `{}`:\n", self.name(db));
+        for (id, expr) in body.exprs.iter() {
+            format_to!(result, "{:?}: {:?}\n", id, expr);
+        }
+
+        result
+    }
 }
 
 // Note: logically, this belongs to `hir_ty`, but we are not using it there yet.