Rollup merge of #160360 - mejrs:hir_pretty, r=nnethercote

Remove rustc_middle dependency on rustc_hir_pretty

There is a `impl PpAnn for TyCtxt`  that is unneeded. None of the big crates (middle, trait_selection) actually do any hir pretty printing so it can be removed and can either be implemented for local structs elsewhere or done by casting to `&dyn PpAnn` instead.

This probably doesn't have any perf effects (its not bottlenecking in timings) but I expect it to compose with #160336 and its followup works quite well.

Old graph:
<img width="1999" height="2171" alt="graph" src="https://github.com/user-attachments/assets/756e6a50-a413-4a8d-a0f3-7bbf4de07933" />

New graph:
<img width="1853" height="2171" alt="graph_hir_pretty" src="https://github.com/user-attachments/assets/f9607e5a-d00b-4a86-8f6a-cefb45b75ad7" />

Author: JonathanBrouwer

Cargo.lock

@@ -3954,6 +3954,7 @@ dependencies = [
  "rustc_errors",
  "rustc_expand",
  "rustc_feature",
+ "rustc_hir",
  "rustc_hir_analysis",
  "rustc_hir_pretty",
  "rustc_index",
@@ -4414,7 +4415,6 @@ dependencies = [
  "rustc_graphviz",
  "rustc_hashes",
  "rustc_hir",
- "rustc_hir_pretty",
  "rustc_index",
  "rustc_lint_defs",
  "rustc_macros",

compiler/rustc_driver_impl/Cargo.toml

@@ -16,6 +16,7 @@ rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
 rustc_expand = { path = "../rustc_expand" }
 rustc_feature = { path = "../rustc_feature" }
+rustc_hir = { path = "../rustc_hir" }
 rustc_hir_analysis = { path = "../rustc_hir_analysis" }
 rustc_hir_pretty = { path = "../rustc_hir_pretty" }
 rustc_index = { path = "../rustc_index" }

compiler/rustc_driver_impl/src/pretty.rs

@@ -7,7 +7,9 @@ use std::io;
 
 use rustc_ast as ast;
 use rustc_ast_pretty::pprust as pprust_ast;
+use rustc_hir::intravisit;
 use rustc_hir_pretty as pprust_hir;
+use rustc_hir_pretty::PpAnn;
 use rustc_middle::bug;
 use rustc_middle::mir::{write_mir_graphviz, write_mir_pretty};
 use rustc_middle::ty::{self, TyCtxt};
@@ -71,7 +73,8 @@ struct HirIdentifiedAnn<'tcx> {
 
 impl<'tcx> pprust_hir::PpAnn for HirIdentifiedAnn<'tcx> {
     fn nested(&self, state: &mut pprust_hir::State<'_>, nested: pprust_hir::Nested) {
-        self.tcx.nested(state, nested)
+        let this = &self.tcx as &dyn intravisit::HirTyCtxt<'_>;
+        this.nested(state, nested)
     }
 
     fn pre(&self, s: &mut pprust_hir::State<'_>, node: pprust_hir::AnnNode<'_>) {
@@ -149,11 +152,12 @@ struct HirTypedAnn<'tcx> {
 
 impl<'tcx> pprust_hir::PpAnn for HirTypedAnn<'tcx> {
     fn nested(&self, state: &mut pprust_hir::State<'_>, nested: pprust_hir::Nested) {
+        let this = &self.tcx as &dyn intravisit::HirTyCtxt<'_>;
         let old_maybe_typeck_results = self.maybe_typeck_results.get();
         if let pprust_hir::Nested::Body(id) = nested {
             self.maybe_typeck_results.set(Some(self.tcx.typeck_body(id)));
         }
-        self.tcx.nested(state, nested);
+        this.nested(state, nested);
         self.maybe_typeck_results.set(old_maybe_typeck_results);
     }
 
@@ -281,7 +285,7 @@ pub fn print<'tcx>(sess: &Session, ppm: PpMode, ex: PrintExtra<'tcx>) {
                 )
             };
             match s {
-                PpHirMode::Normal => f(&tcx),
+                PpHirMode::Normal => f(&(&tcx as &dyn intravisit::HirTyCtxt<'_>) as &dyn PpAnn),
                 PpHirMode::Identified => {
                     let annotation = HirIdentifiedAnn { tcx };
                     f(&annotation)

compiler/rustc_hir_typeck/src/_match.rs

@@ -421,7 +421,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     return self.get_fn_decl(hir_id).map(|(_, fn_decl)| {
                         let (ty, span) = match fn_decl.output {
                             hir::FnRetTy::DefaultReturn(span) => ("()".to_string(), span),
-                            hir::FnRetTy::Return(ty) => (ty_to_string(&self.tcx, ty), ty.span),
+                            hir::FnRetTy::Return(ty) => (ty_to_string(self, ty), ty.span),
                         };
                         (span, format!("expected `{ty}` because of this return type"))
                     });

compiler/rustc_hir_typeck/src/callee.rs

@@ -903,7 +903,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             };
             let removal_span = callee_expr.span.shrink_to_hi().to(call_expr.span.shrink_to_hi());
             unit_variant =
-                Some((removal_span, descr, rustc_hir_pretty::qpath_to_string(&self.tcx, qpath)));
+                Some((removal_span, descr, rustc_hir_pretty::qpath_to_string(self, qpath)));
         }
 
         let callee_ty = self.resolve_vars_if_possible(callee_ty);

compiler/rustc_hir_typeck/src/expr.rs

@@ -50,7 +50,7 @@ use crate::diagnostics::{
 use crate::op::contains_let_in_chain;
 use crate::{
     BreakableCtxt, CoroutineTypes, Diverges, FnCtxt, GatherLocalsVisitor, Needs,
-    TupleArgumentsFlag, cast, fatally_break_rust, report_unexpected_variant_res, type_error_struct,
+    TupleArgumentsFlag, cast, fatally_break_rust, type_error_struct,
 };
 
 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
@@ -589,8 +589,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 Ty::new_error(tcx, e)
             }
             Res::Def(DefKind::Variant, _) => {
-                let e = report_unexpected_variant_res(
-                    tcx,
+                let e = self.report_unexpected_variant_res(
                     res,
                     Some(expr),
                     &[],

compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs

@@ -220,6 +220,16 @@ impl<'a, 'tcx> Deref for FnCtxt<'a, 'tcx> {
     }
 }
 
+impl<'tcx> rustc_hir_pretty::PpAnn for FnCtxt<'_, 'tcx> {
+    fn nested(&self, state: &mut rustc_hir_pretty::State<'_>, nested: rustc_hir_pretty::Nested) {
+        rustc_hir_pretty::PpAnn::nested(
+            &(&self.tcx as &dyn rustc_hir::intravisit::HirTyCtxt<'_>),
+            state,
+            nested,
+        )
+    }
+}
+
 impl<'tcx> HirTyLowerer<'tcx> for FnCtxt<'_, 'tcx> {
     fn tcx(&self) -> TyCtxt<'tcx> {
         self.tcx

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -723,12 +723,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let hir::FnDecl { inputs, output, .. } = fn_ptr_ty.decl;
 
         let inputs_str =
-            inputs.iter().map(|ty| rustc_hir_pretty::ty_to_string(&self.tcx, ty)).join(", ");
+            inputs.iter().map(|ty| rustc_hir_pretty::ty_to_string(self, ty)).join(", ");
 
         let output_str = match output {
             hir::FnRetTy::DefaultReturn(_) => String::new(),
             hir::FnRetTy::Return(ty) => {
-                format!(" -> {}", rustc_hir_pretty::ty_to_string(&self.tcx, ty))
+                format!(" -> {}", rustc_hir_pretty::ty_to_string(self, ty))
             }
         };
 

compiler/rustc_hir_typeck/src/lib.rs

@@ -478,134 +478,138 @@ impl<'tcx> EnclosingBreakables<'tcx> {
         }
     }
 }
-
-fn report_unexpected_variant_res(
-    tcx: TyCtxt<'_>,
-    res: Res,
-    expr: Option<&hir::Expr<'_>>,
-    sub_pats: &[hir::Pat<'_>],
-    qpath: &hir::QPath<'_>,
-    span: Span,
-    err_code: ErrCode,
-    expected: &str,
-) -> ErrorGuaranteed {
-    let res_descr = match res {
-        Res::Def(DefKind::Variant, _) => "struct variant",
-        _ => res.descr(),
-    };
-    let path_str = rustc_hir_pretty::qpath_to_string(&tcx, qpath);
-    let mut err = tcx
-        .dcx()
-        .struct_span_err(span, format!("expected {expected}, found {res_descr} `{path_str}`"))
-        .with_code(err_code);
-    match res {
-        Res::Def(DefKind::Fn | DefKind::AssocFn, _) if err_code == E0164 => {
-            let patterns_url = "https://doc.rust-lang.org/book/ch19-00-patterns.html";
-            err.with_span_label(span, "`fn` calls are not allowed in patterns")
-                .with_help(format!("for more information, visit {patterns_url}"))
-        }
-        Res::Def(DefKind::Variant, _) if let Some(expr) = expr => {
-            err.span_label(span, format!("not a {expected}"));
-            let variant = tcx.expect_variant_res(res);
-            let sugg = if variant.fields.is_empty() {
-                " {}".to_string()
-            } else {
-                format!(
-                    " {{ {} }}",
-                    variant
-                        .fields
-                        .iter()
-                        .map(|f| format!("{}: /* value */", f.name))
-                        .collect::<Vec<_>>()
-                        .join(", ")
-                )
-            };
-            let descr = "you might have meant to create a new value of the struct";
-            let mut suggestion = vec![];
-            match tcx.parent_hir_node(expr.hir_id) {
-                hir::Node::Expr(hir::Expr {
-                    kind: hir::ExprKind::Call(..),
-                    span: call_span,
-                    ..
-                }) => {
-                    suggestion.push((span.shrink_to_hi().with_hi(call_span.hi()), sugg));
-                }
-                hir::Node::Expr(hir::Expr { kind: hir::ExprKind::Binary(..), hir_id, .. }) => {
-                    suggestion.push((expr.span.shrink_to_lo(), "(".to_string()));
-                    if let hir::Node::Expr(parent) = tcx.parent_hir_node(*hir_id)
-                        && let hir::ExprKind::If(condition, block, None) = parent.kind
-                        && condition.hir_id == *hir_id
-                        && let hir::ExprKind::Block(block, _) = block.kind
-                        && block.stmts.is_empty()
-                        && let Some(expr) = block.expr
-                        && let hir::ExprKind::Path(..) = expr.kind
-                    {
-                        // Special case: you can incorrectly write an equality condition:
-                        // if foo == Struct { field } { /* if body */ }
-                        // which should have been written
-                        // if foo == (Struct { field }) { /* if body */ }
-                        suggestion.push((block.span.shrink_to_hi(), ")".to_string()));
-                    } else {
-                        suggestion.push((span.shrink_to_hi().with_hi(expr.span.hi()), sugg));
+impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
+    fn report_unexpected_variant_res(
+        &self,
+        res: Res,
+        expr: Option<&hir::Expr<'_>>,
+        sub_pats: &[hir::Pat<'_>],
+        qpath: &hir::QPath<'_>,
+        span: Span,
+        err_code: ErrCode,
+        expected: &str,
+    ) -> ErrorGuaranteed {
+        let tcx = self.tcx;
+        let res_descr = match res {
+            Res::Def(DefKind::Variant, _) => "struct variant",
+            _ => res.descr(),
+        };
+        let path_str = rustc_hir_pretty::qpath_to_string(self, qpath);
+        let mut err = tcx
+            .dcx()
+            .struct_span_err(span, format!("expected {expected}, found {res_descr} `{path_str}`"))
+            .with_code(err_code);
+        match res {
+            Res::Def(DefKind::Fn | DefKind::AssocFn, _) if err_code == E0164 => {
+                let patterns_url = "https://doc.rust-lang.org/book/ch19-00-patterns.html";
+                err.with_span_label(span, "`fn` calls are not allowed in patterns")
+                    .with_help(format!("for more information, visit {patterns_url}"))
+            }
+            Res::Def(DefKind::Variant, _) if let Some(expr) = expr => {
+                err.span_label(span, format!("not a {expected}"));
+                let variant = tcx.expect_variant_res(res);
+                let sugg = if variant.fields.is_empty() {
+                    " {}".to_string()
+                } else {
+                    format!(
+                        " {{ {} }}",
+                        variant
+                            .fields
+                            .iter()
+                            .map(|f| format!("{}: /* value */", f.name))
+                            .collect::<Vec<_>>()
+                            .join(", ")
+                    )
+                };
+                let descr = "you might have meant to create a new value of the struct";
+                let mut suggestion = vec![];
+                match tcx.parent_hir_node(expr.hir_id) {
+                    hir::Node::Expr(hir::Expr {
+                        kind: hir::ExprKind::Call(..),
+                        span: call_span,
+                        ..
+                    }) => {
+                        suggestion.push((span.shrink_to_hi().with_hi(call_span.hi()), sugg));
+                    }
+                    hir::Node::Expr(hir::Expr {
+                        kind: hir::ExprKind::Binary(..), hir_id, ..
+                    }) => {
+                        suggestion.push((expr.span.shrink_to_lo(), "(".to_string()));
+                        if let hir::Node::Expr(parent) = tcx.parent_hir_node(*hir_id)
+                            && let hir::ExprKind::If(condition, block, None) = parent.kind
+                            && condition.hir_id == *hir_id
+                            && let hir::ExprKind::Block(block, _) = block.kind
+                            && block.stmts.is_empty()
+                            && let Some(expr) = block.expr
+                            && let hir::ExprKind::Path(..) = expr.kind
+                        {
+                            // Special case: you can incorrectly write an equality condition:
+                            // if foo == Struct { field } { /* if body */ }
+                            // which should have been written
+                            // if foo == (Struct { field }) { /* if body */ }
+                            suggestion.push((block.span.shrink_to_hi(), ")".to_string()));
+                        } else {
+                            suggestion.push((span.shrink_to_hi().with_hi(expr.span.hi()), sugg));
+                        }
+                    }
+                    _ => {
+                        suggestion.push((span.shrink_to_hi(), sugg));
                     }
                 }
-                _ => {
-                    suggestion.push((span.shrink_to_hi(), sugg));
-                }
+
+                err.multipart_suggestion(descr, suggestion, Applicability::HasPlaceholders);
+                err
             }
+            Res::Def(DefKind::Variant, _) if expr.is_none() => {
+                err.span_label(span, format!("not a {expected}"));
 
-            err.multipart_suggestion(descr, suggestion, Applicability::HasPlaceholders);
-            err
-        }
-        Res::Def(DefKind::Variant, _) if expr.is_none() => {
-            err.span_label(span, format!("not a {expected}"));
-
-            let fields = &tcx.expect_variant_res(res).fields.raw;
-            let span = qpath.span().shrink_to_hi().to(span.shrink_to_hi());
-            let (msg, sugg) = if fields.is_empty() {
-                ("use the struct variant pattern syntax", " {}".to_string())
-            } else {
-                let msg = if fields.is_empty() {
-                    "use struct variant pattern syntax"
+                let fields = &tcx.expect_variant_res(res).fields.raw;
+                let span = qpath.span().shrink_to_hi().to(span.shrink_to_hi());
+                let (msg, sugg) = if fields.is_empty() {
+                    ("use the struct variant pattern syntax", " {}".to_string())
                 } else {
-                    "add the names to match a struct variant's fields"
+                    let msg = if fields.is_empty() {
+                        "use struct variant pattern syntax"
+                    } else {
+                        "add the names to match a struct variant's fields"
+                    };
+                    let fields_sugg = fields
+                        .iter()
+                        .enumerate()
+                        .map(|(i, field)| {
+                            let field_name = field.ident(tcx).to_string();
+
+                            let pat_snippet = sub_pats
+                                .get(i)
+                                .and_then(|sub_pat| {
+                                    tcx.sess.source_map().span_to_snippet(sub_pat.span).ok()
+                                })
+                                .unwrap_or_else(|| "_".to_string());
+
+                            if field_name == pat_snippet {
+                                field_name
+                            } else {
+                                format!("{field_name}: {pat_snippet}")
+                            }
+                        })
+                        .collect::<Vec<_>>()
+                        .join(", ");
+                    let sugg = format!(" {{ {} }}", fields_sugg);
+                    (msg, sugg)
                 };
-                let fields_sugg = fields
-                    .iter()
-                    .enumerate()
-                    .map(|(i, field)| {
-                        let field_name = field.ident(tcx).to_string();
-
-                        let pat_snippet = sub_pats
-                            .get(i)
-                            .and_then(|sub_pat| {
-                                tcx.sess.source_map().span_to_snippet(sub_pat.span).ok()
-                            })
-                            .unwrap_or_else(|| "_".to_string());
-
-                        if field_name == pat_snippet {
-                            field_name
-                        } else {
-                            format!("{field_name}: {pat_snippet}")
-                        }
-                    })
-                    .collect::<Vec<_>>()
-                    .join(", ");
-                let sugg = format!(" {{ {} }}", fields_sugg);
-                (msg, sugg)
-            };
-
-            err.span_suggestion_verbose(
-                qpath.span().shrink_to_hi().to(span.shrink_to_hi()),
-                msg,
-                sugg,
-                Applicability::HasPlaceholders,
-            );
-            err
+
+                err.span_suggestion_verbose(
+                    qpath.span().shrink_to_hi().to(span.shrink_to_hi()),
+                    msg,
+                    sugg,
+                    Applicability::HasPlaceholders,
+                );
+                err
+            }
+            _ => err.with_span_label(span, format!("not a {expected}")),
         }
-        _ => err.with_span_label(span, format!("not a {expected}")),
+        .emit()
     }
-    .emit()
 }
 
 /// Controls whether all arguments are tupled. This is used for the call operator only.