Auto merge of #85020 - lrh2000:named-upvars, r=tmandry

Name the captured upvars for closures/generators in debuginfo

Previously, debuggers print closures as something like
```
y::main::closure-0 (0x7fffffffdd34)
```
The pointer actually references to an upvar. It is not very obvious, especially for beginners.

It's because upvars don't have names before, as they are packed into a tuple. This PR names the upvars, so we can expect to see something like
```
y::main::closure-0 {_captured_ref__b: 0x[...]}
```

r? `@tmandry`
Discussed at https://github.com/rust-lang/rust/pull/84752#issuecomment-831639489 .

4 files changed, 161 insertions, 7 deletions

diff --git a/src/test/debuginfo/captured-fields-1.rs b/src/test/debuginfo/captured-fields-1.rs
new file mode 100644
index 00000000000..65f9e5f5322
--- /dev/null
+++ b/src/test/debuginfo/captured-fields-1.rs
@@ -0,0 +1,99 @@
+// compile-flags:-g
+
+// === GDB TESTS ===================================================================================
+
+// gdb-command:run
+// gdb-command:print test
+// gdbr-check:$1 = captured_fields_1::main::{closure#0} {_ref__my_ref__my_field1: 0x[...]}
+// gdb-command:continue
+// gdb-command:print test
+// gdbr-check:$2 = captured_fields_1::main::{closure#1} {_ref__my_ref__my_field2: 0x[...]}
+// gdb-command:continue
+// gdb-command:print test
+// gdbr-check:$3 = captured_fields_1::main::{closure#2} {_ref__my_ref: 0x[...]}
+// gdb-command:continue
+// gdb-command:print test
+// gdbr-check:$4 = captured_fields_1::main::{closure#3} {my_ref: 0x[...]}
+// gdb-command:continue
+// gdb-command:print test
+// gdbr-check:$5 = captured_fields_1::main::{closure#4} {my_var__my_field2: 22}
+// gdb-command:continue
+// gdb-command:print test
+// gdbr-check:$6 = captured_fields_1::main::{closure#5} {my_var: captured_fields_1::MyStruct {my_field1: 11, my_field2: 22}}
+// gdb-command:continue
+
+// === LLDB TESTS ==================================================================================
+
+// lldb-command:run
+// lldb-command:print test
+// lldbg-check:(captured_fields_1::main::{closure#0}) $0 = { _ref__my_ref__my_field1 = 0x[...] }
+// lldb-command:continue
+// lldb-command:print test
+// lldbg-check:(captured_fields_1::main::{closure#1}) $1 = { _ref__my_ref__my_field2 = 0x[...] }
+// lldb-command:continue
+// lldb-command:print test
+// lldbg-check:(captured_fields_1::main::{closure#2}) $2 = { _ref__my_ref = 0x[...] }
+// lldb-command:continue
+// lldb-command:print test
+// lldbg-check:(captured_fields_1::main::{closure#3}) $3 = { my_ref = 0x[...] }
+// lldb-command:continue
+// lldb-command:print test
+// lldbg-check:(captured_fields_1::main::{closure#4}) $4 = { my_var__my_field2 = 22 }
+// lldb-command:continue
+// lldb-command:print test
+// lldbg-check:(captured_fields_1::main::{closure#5}) $5 = { my_var = { my_field1 = 11 my_field2 = 22 } }
+// lldb-command:continue
+
+#![feature(capture_disjoint_fields)]
+#![allow(unused)]
+
+struct MyStruct {
+    my_field1: u32,
+    my_field2: u32,
+}
+
+fn main() {
+    let mut my_var = MyStruct {
+        my_field1: 11,
+        my_field2: 22,
+    };
+    let my_ref = &mut my_var;
+
+    let test = || {
+        let a = &mut my_ref.my_field1;
+    };
+
+    _zzz(); // #break
+
+    let test = || {
+        let a = &my_ref.my_field2;
+    };
+
+    _zzz(); // #break
+
+    let test = || {
+        let a = &my_ref;
+    };
+
+    _zzz(); // #break
+
+    let test = || {
+        let a = my_ref;
+    };
+
+    _zzz(); // #break
+
+    let test = move || {
+        let a = my_var.my_field2;
+    };
+
+    _zzz(); // #break
+
+    let test = || {
+        let a = my_var;
+    };
+
+    _zzz(); // #break
+}
+
+fn _zzz() {}
diff --git a/src/test/debuginfo/captured-fields-2.rs b/src/test/debuginfo/captured-fields-2.rs
new file mode 100644
index 00000000000..c872354a924
--- /dev/null
+++ b/src/test/debuginfo/captured-fields-2.rs
@@ -0,0 +1,55 @@
+// compile-flags:-g
+
+// === GDB TESTS ===================================================================================
+
+// gdb-command:run
+// gdb-command:print my_ref__my_field1
+// gdbr-check:$1 = 11
+// gdb-command:continue
+// gdb-command:print my_var__my_field2
+// gdbr-check:$2 = 22
+// gdb-command:continue
+
+// === LLDB TESTS ==================================================================================
+
+// lldb-command:run
+// lldb-command:print my_ref__my_field1
+// lldbg-check:(unsigned int) $0 = 11
+// lldb-command:continue
+// lldb-command:print my_var__my_field2
+// lldbg-check:(unsigned int) $1 = 22
+// lldb-command:continue
+
+#![feature(capture_disjoint_fields)]
+#![allow(unused)]
+
+struct MyStruct {
+    my_field1: u32,
+    my_field2: u32,
+}
+
+fn main() {
+    let mut my_var = MyStruct {
+        my_field1: 11,
+        my_field2: 22,
+    };
+    let my_ref = &mut my_var;
+
+    let test = || {
+        let a = my_ref.my_field1;
+
+        _zzz(); // #break
+    };
+
+    test();
+
+    let test = move || {
+        let a = my_var.my_field2;
+
+        _zzz(); // #break
+    };
+
+    test();
+}
+
+fn _zzz() {}
diff --git a/src/test/debuginfo/generator-objects.rs b/src/test/debuginfo/generator-objects.rs
index 7ac3304aa96..9bf33a7bb87 100644
--- a/src/test/debuginfo/generator-objects.rs
+++ b/src/test/debuginfo/generator-objects.rs
@@ -11,16 +11,16 @@
 
 // gdb-command:run
 // gdb-command:print b
-// gdb-check:$1 = generator_objects::main::{generator#0}::Unresumed(0x[...])
+// gdb-check:$1 = generator_objects::main::{generator#0}::Unresumed{_ref__a: 0x[...]}
 // gdb-command:continue
 // gdb-command:print b
-// gdb-check:$2 = generator_objects::main::{generator#0}::Suspend0{c: 6, d: 7, __0: 0x[...]}
+// gdb-check:$2 = generator_objects::main::{generator#0}::Suspend0{c: 6, d: 7, _ref__a: 0x[...]}
 // gdb-command:continue
 // gdb-command:print b
-// gdb-check:$3 = generator_objects::main::{generator#0}::Suspend1{c: 7, d: 8, __0: 0x[...]}
+// gdb-check:$3 = generator_objects::main::{generator#0}::Suspend1{c: 7, d: 8, _ref__a: 0x[...]}
 // gdb-command:continue
 // gdb-command:print b
-// gdb-check:$4 = generator_objects::main::{generator#0}::Returned(0x[...])
+// gdb-check:$4 = generator_objects::main::{generator#0}::Returned{_ref__a: 0x[...]}
 
 // === LLDB TESTS ==================================================================================
 
diff --git a/src/test/debuginfo/issue-57822.rs b/src/test/debuginfo/issue-57822.rs
index f6d2146fe11..1a26b0a3255 100644
--- a/src/test/debuginfo/issue-57822.rs
+++ b/src/test/debuginfo/issue-57822.rs
@@ -11,17 +11,17 @@
 // gdb-command:run
 
 // gdb-command:print g
-// gdb-check:$1 = issue_57822::main::{closure#1} (issue_57822::main::{closure#0} (1))
+// gdb-check:$1 = issue_57822::main::{closure#1} {f: issue_57822::main::{closure#0} {x: 1}}
 
 // gdb-command:print b
-// gdb-check:$2 = issue_57822::main::{generator#3}::Unresumed(issue_57822::main::{generator#2}::Unresumed(2))
+// gdb-check:$2 = issue_57822::main::{generator#3}::Unresumed{a: issue_57822::main::{generator#2}::Unresumed{y: 2}}
 
 // === LLDB TESTS ==================================================================================
 
 // lldb-command:run
 
 // lldb-command:print g
-// lldbg-check:(issue_57822::main::{closure#1}) $0 = { 0 = { 0 = 1 } }
+// lldbg-check:(issue_57822::main::{closure#1}) $0 = { f = { x = 1 } }
 
 // lldb-command:print b
 // lldbg-check:(issue_57822::main::{generator#3}) $1 =