add pretty printing

compiler/rustc_hir_pretty/src/lib.rs

@@ -17,9 +17,9 @@ use rustc_ast_pretty::pprust::state::MacHeader;
 use rustc_ast_pretty::pprust::{Comments, PrintState};
 use rustc_hir::attrs::{AttributeKind, PrintAttribute};
 use rustc_hir::{
-    BindingMode, ByRef, ConstArgKind, GenericArg, GenericBound, GenericParam, GenericParamKind,
-    HirId, ImplicitSelfKind, LifetimeParamKind, Node, PatKind, PreciseCapturingArg, RangeEnd, Term,
-    TyPatKind,
+    BindingMode, ByRef, ConstArg, ConstArgExprField, ConstArgKind, GenericArg, GenericBound,
+    GenericParam, GenericParamKind, HirId, ImplicitSelfKind, LifetimeParamKind, Node, PatKind,
+    PreciseCapturingArg, RangeEnd, Term, TyPatKind,
 };
 use rustc_span::source_map::SourceMap;
 use rustc_span::{FileName, Ident, Span, Symbol, kw, sym};
@@ -1137,9 +1137,8 @@ impl<'a> State<'a> {
 
     fn print_const_arg(&mut self, const_arg: &hir::ConstArg<'_>) {
         match &const_arg.kind {
-            // FIXME(mgca): proper printing for struct exprs
-            ConstArgKind::Struct(..) => self.word("/* STRUCT EXPR */"),
-            ConstArgKind::TupleCall(..) => self.word("/* TUPLE CALL */"),
+            ConstArgKind::Struct(qpath, fields) => self.print_const_struct(qpath, fields),
+            ConstArgKind::TupleCall(qpath, args) => self.print_const_ctor(qpath, args),
             ConstArgKind::Path(qpath) => self.print_qpath(qpath, true),
             ConstArgKind::Anon(anon) => self.print_anon_const(anon),
             ConstArgKind::Error(_, _) => self.word("/*ERROR*/"),
@@ -1147,6 +1146,31 @@ impl<'a> State<'a> {
         }
     }
 
+    fn print_const_struct(&mut self, qpath: &hir::QPath<'_>, fields: &&[&ConstArgExprField<'_>]) {
+        self.print_qpath(qpath, true);
+        self.word(" ");
+        self.word("{");
+        if !fields.is_empty() {
+            self.nbsp();
+        }
+        self.commasep(Inconsistent, *fields, |s, field| {
+            s.word(field.field.as_str().to_string());
+            s.word(":");
+            s.nbsp();
+            s.print_const_arg(field.expr);
+        });
+        self.word("}");
+    }
+
+    fn print_const_ctor(&mut self, qpath: &hir::QPath<'_>, args: &&[&ConstArg<'_, ()>]) {
+        self.print_qpath(qpath, true);
+        self.word("(");
+        self.commasep(Inconsistent, *args, |s, arg| {
+            s.print_const_arg(arg);
+        });
+        self.word(")");
+    }
+
     fn print_call_post(&mut self, args: &[hir::Expr<'_>]) {
         self.popen();
         self.commasep_exprs(Inconsistent, args);

tests/ui/unpretty/struct-exprs-tuple-call-pretty-printing.rs

@@ -0,0 +1,33 @@
+//@ compile-flags: -Zunpretty=hir
+//@ check-pass
+
+#![feature(min_generic_const_args, adt_const_params)]
+#![expect(incomplete_features)]
+#![allow(dead_code)]
+
+use std::marker::ConstParamTy;
+
+struct Point(u32, u32);
+
+struct Point3();
+
+struct Point1 {
+    a: u32,
+    b: u32,
+}
+
+struct Point2 {}
+
+fn with_point<const P: Point>() {}
+fn with_point1<const P: Point1>() {}
+fn with_point2<const P: Point2>() {}
+fn with_point3<const P: Point3>() {}
+
+fn test<const N: u32>() {
+    with_point::<{ Point(N, N) }>();
+    with_point1::<{ Point1 { a: N, b: N } }>();
+    with_point2::<{ Point2 {} }>();
+    with_point3::<{ Point3() }>();
+}
+
+fn main() {}

tests/ui/unpretty/struct-exprs-tuple-call-pretty-printing.stdout

@@ -0,0 +1,39 @@
+//@ compile-flags: -Zunpretty=hir
+//@ check-pass
+
+#![feature(min_generic_const_args, adt_const_params)]
+#![expect(incomplete_features)]
+#![allow(dead_code)]
+#[attr = MacroUse {arguments: UseAll}]
+extern crate std;
+#[prelude_import]
+use ::std::prelude::rust_2015::*;
+
+use std::marker::ConstParamTy;
+
+struct Point(u32, u32);
+
+struct Point3();
+
+struct Point1 {
+    a: u32,
+    b: u32,
+}
+
+struct Point2 {
+}
+
+fn with_point<const P: Point>() { }
+fn with_point1<const P: Point1>() { }
+fn with_point2<const P: Point2>() { }
+fn with_point3<const P: Point3>() { }
+
+fn test<const N:
+    u32>() {
+    with_point::<Point(N, N)>();
+    with_point1::<Point1 { a: N, b: N}>();
+    with_point2::<Point2 {}>();
+    with_point3::<Point3()>();
+}
+
+fn main() { }