Support -Z unpretty=thir-tree again

Cargo.lock

@@ -3726,6 +3726,7 @@ dependencies = [
  "rustc_session",
  "rustc_span",
  "rustc_target",
+ "rustc_typeck",
  "tracing",
  "tracing-subscriber",
  "tracing-tree",

compiler/rustc_driver/Cargo.toml

@@ -34,6 +34,7 @@ rustc_interface = { path = "../rustc_interface" }
 rustc_serialize = { path = "../rustc_serialize" }
 rustc_ast = { path = "../rustc_ast" }
 rustc_span = { path = "../rustc_span" }
+rustc_typeck = { path = "../rustc_typeck" }
 
 [target.'cfg(windows)'.dependencies]
 winapi = { version = "0.3", features = ["consoleapi", "debugapi", "processenv"] }

compiler/rustc_driver/src/pretty.rs

@@ -14,6 +14,7 @@ use rustc_span::symbol::Ident;
 use rustc_span::FileName;
 
 use std::cell::Cell;
+use std::fmt::Write;
 use std::path::Path;
 
 pub use self::PpMode::*;
@@ -471,7 +472,6 @@ fn print_with_analysis(
     ofile: Option<&Path>,
 ) -> Result<(), ErrorReported> {
     tcx.analysis(())?;
-
     let out = match ppm {
         Mir => {
             let mut out = Vec::new();
@@ -486,8 +486,18 @@ fn print_with_analysis(
         }
 
         ThirTree => {
-            // FIXME(rust-lang/project-thir-unsafeck#8)
+            let mut out = String::new();
-            todo!()
+            abort_on_err(rustc_typeck::check_crate(tcx), tcx.sess);
+            debug!("pretty printing THIR tree");
+            for did in tcx.body_owners() {
+                let _ = writeln!(
+                    out,
+                    "{:?}:\n{}\n",
+                    did,
+                    tcx.thir_tree(ty::WithOptConstParam::unknown(did))
+                );
+            }
+            out
         }
 
         _ => unreachable!(),

compiler/rustc_middle/src/query/mod.rs

@@ -230,6 +230,12 @@ rustc_queries! {
         desc { |tcx| "building THIR for `{}`", tcx.def_path_str(key.did.to_def_id()) }
     }
 
+    /// Create a THIR tree for debugging.
+    query thir_tree(key: ty::WithOptConstParam<LocalDefId>) -> String {
+        no_hash
+        desc { |tcx| "constructing THIR tree for `{}`", tcx.def_path_str(key.did.to_def_id()) }
+    }
+
     /// Set of all the `DefId`s in this crate that have MIR associated with
     /// them. This includes all the body owners, but also things like struct
     /// constructors.

compiler/rustc_mir_build/src/lib.rs

@@ -30,4 +30,5 @@ pub fn provide(providers: &mut Providers) {
     providers.thir_check_unsafety = check_unsafety::thir_check_unsafety;
     providers.thir_check_unsafety_for_const_arg = check_unsafety::thir_check_unsafety_for_const_arg;
     providers.thir_body = thir::cx::thir_body;
+    providers.thir_tree = thir::cx::thir_tree;
 }

compiler/rustc_mir_build/src/thir/cx/mod.rs

@@ -30,6 +30,13 @@ crate fn thir_body<'tcx>(
     (tcx.alloc_steal_thir(cx.thir), expr)
 }
 
+crate fn thir_tree<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    owner_def: ty::WithOptConstParam<LocalDefId>,
+) -> String {
+    format!("{:#?}", thir_body(tcx, owner_def).0.steal())
+}
+
 struct Cx<'tcx> {
     tcx: TyCtxt<'tcx>,
     thir: Thir<'tcx>,