From 5e46d8675cd924e981aac9fd6ca146d627e9d4ab Mon Sep 17 00:00:00 2001
From: Sarthak Singh <ss269@uw.edu>
Date: Sun, 23 Oct 2022 12:29:59 +0530
Subject: [PATCH] Added helper to prevent verbose printing from the
 `PrettyPrinter` when printing constants

---
 .../src/interpret/intrinsics/type_name.rs           |  6 ++++--
 compiler/rustc_middle/src/ty/print/pretty.rs        | 10 +++++++---
 src/test/ui/type/issue-94187-verbose-type-name.rs   | 13 +++++++++++++
 3 files changed, 24 insertions(+), 5 deletions(-)
 create mode 100644 src/test/ui/type/issue-94187-verbose-type-name.rs

diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs b/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs
index 7e4c5fcb031b0..ffdb8de5b6c8c 100644
--- a/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs
+++ b/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs
@@ -4,7 +4,7 @@ use rustc_hir::definitions::DisambiguatedDefPathData;
 use rustc_middle::mir::interpret::{Allocation, ConstAllocation};
 use rustc_middle::ty::{
     self,
-    print::{PrettyPrinter, Print, Printer},
+    print::{with_no_verbose_constants, PrettyPrinter, Print, Printer},
     subst::{GenericArg, GenericArgKind},
     Ty, TyCtxt,
 };
@@ -190,7 +190,9 @@ impl Write for AbsolutePathPrinter<'_> {
 
 /// Directly returns an `Allocation` containing an absolute path representation of the given type.
 pub(crate) fn alloc_type_name<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> ConstAllocation<'tcx> {
-    let path = AbsolutePathPrinter { tcx, path: String::new() }.print_type(ty).unwrap().path;
+    let path = with_no_verbose_constants!(
+        AbsolutePathPrinter { tcx, path: String::new() }.print_type(ty).unwrap().path
+    );
     let alloc = Allocation::from_bytes_byte_aligned_immutable(path.into_bytes());
     tcx.intern_const_alloc(alloc)
 }
diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
index b8ee2b994b1e4..c1c2e162f2839 100644
--- a/compiler/rustc_middle/src/ty/print/pretty.rs
+++ b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -63,6 +63,7 @@ thread_local! {
     static NO_TRIMMED_PATH: Cell<bool> = const { Cell::new(false) };
     static NO_QUERIES: Cell<bool> = const { Cell::new(false) };
     static NO_VISIBLE_PATH: Cell<bool> = const { Cell::new(false) };
+    static NO_VERBOSE_CONSTANTS: Cell<bool> = const { Cell::new(false) };
 }
 
 macro_rules! define_helper {
@@ -117,6 +118,9 @@ define_helper!(
     /// Prevent selection of visible paths. `Display` impl of DefId will prefer
     /// visible (public) reexports of types as paths.
     fn with_no_visible_paths(NoVisibleGuard, NO_VISIBLE_PATH);
+    /// Prevent verbose printing of constants. Verbose printing of constants is
+    /// never desirable in some contexts like `std::any::type_name`.
+    fn with_no_verbose_constants(NoVerboseConstantsGuard, NO_VERBOSE_CONSTANTS);
 );
 
 /// The "region highlights" are used to control region printing during
@@ -759,7 +763,7 @@ pub trait PrettyPrinter<'tcx>:
             }
             ty::Array(ty, sz) => {
                 p!("[", print(ty), "; ");
-                if self.tcx().sess.verbose() {
+                if !NO_VERBOSE_CONSTANTS.with(|flag| flag.get()) && self.tcx().sess.verbose() {
                     p!(write("{:?}", sz));
                 } else if let ty::ConstKind::Unevaluated(..) = sz.kind() {
                     // Do not try to evaluate unevaluated constants. If we are const evaluating an
@@ -1181,7 +1185,7 @@ pub trait PrettyPrinter<'tcx>:
     ) -> Result<Self::Const, Self::Error> {
         define_scoped_cx!(self);
 
-        if self.tcx().sess.verbose() {
+        if !NO_VERBOSE_CONSTANTS.with(|flag| flag.get()) && self.tcx().sess.verbose() {
             p!(write("Const({:?}: {:?})", ct.kind(), ct.ty()));
             return Ok(self);
         }
@@ -1416,7 +1420,7 @@ pub trait PrettyPrinter<'tcx>:
     ) -> Result<Self::Const, Self::Error> {
         define_scoped_cx!(self);
 
-        if self.tcx().sess.verbose() {
+        if !NO_VERBOSE_CONSTANTS.with(|flag| flag.get()) && self.tcx().sess.verbose() {
             p!(write("ValTree({:?}: ", valtree), print(ty), ")");
             return Ok(self);
         }
diff --git a/src/test/ui/type/issue-94187-verbose-type-name.rs b/src/test/ui/type/issue-94187-verbose-type-name.rs
new file mode 100644
index 0000000000000..902ef5ade2b0e
--- /dev/null
+++ b/src/test/ui/type/issue-94187-verbose-type-name.rs
@@ -0,0 +1,13 @@
+// Check to insure that the output of `std::any::type_name` does not change based on -Zverbose
+// when printing constants
+// run-pass
+// edition: 2018
+// revisions: normal verbose
+// [verbose]compile-flags:-Zverbose
+
+struct Wrapper<const VALUE: usize>;
+
+fn main() {
+    assert_eq!(std::any::type_name::<[u32; 0]>(), "[u32; 0]");
+    assert_eq!(std::any::type_name::<Wrapper<0>>(), "issue_94187_verbose_type_name::Wrapper<0>");
+}