[RFA 2/2] Set TYPE_NAME for Rust unions

[Tom Tromey <tom@tromey.com>]

I noticed that read_structure_type sets TYPE_NAME to TYPE_TAG_NAME for
some things, but not for unions.  For Rust, I think we want to do this
for all types, so this patch adds the needed code.

I think that TYPE_TAG_NAME is confusing and should probably be
removed.  I am working on a patch to do this, but in the meantime this
seemed like a reasonable change to apply.  I suspect this change would
be ok for C++ as well, but I do not know about D.

2018-04-12  Tom Tromey  <tom@tromey.com>

	* dwarf2read.c (read_structure_type): Set TYPE_NAME for rust
	unions.
---
 gdb/ChangeLog    | 5 +++++
 gdb/dwarf2read.c | 4 +++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index ceaa5f92ab..f2bb3d0af3 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
 2018-04-12  Tom Tromey  <tom@tromey.com>
 
+	* dwarf2read.c (read_structure_type): Set TYPE_NAME for rust
+	unions.
+
+2018-04-12  Tom Tromey  <tom@tromey.com>
+
 	* dwarf2read.c (quirk_rust_enum): Conditionally drop the
 	discriminant field.
 
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 4207e4c531..e3f544a6a4 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -15631,7 +15631,9 @@ read_structure_type (struct die_info *die, struct dwarf2_cu *cu)
 
 	  TYPE_TAG_NAME (type) = full_name;
 	  if (die->tag == DW_TAG_structure_type
-	      || die->tag == DW_TAG_class_type)
+	      || die->tag == DW_TAG_class_type
+	      || (cu->language == language_rust
+		  && die->tag == DW_TAG_union_type))
 	    TYPE_NAME (type) = TYPE_TAG_NAME (type);
 	}
       else
-- 
2.13.6