From 6f92b1c1f2086dfe7b478290e76469e64d24bfbd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emilio=20Cobos=20=C3=81lvarez?= <emilio@crisal.io>
Date: Tue, 9 Jul 2019 15:34:07 +0200
Subject: [PATCH] Improve workaround for LLVM bug when evaluating
 value-dependent expressions.

Using the canonical type makes it work across typedefs.

Fixes #1590
---
 src/clang.rs                                  | 36 +++++++++----------
 .../tests/eval-value-dependent.rs             | 15 ++++++++
 tests/headers/eval-value-dependent.hpp        |  6 ++++
 3 files changed, 38 insertions(+), 19 deletions(-)
 create mode 100644 tests/expectations/tests/eval-value-dependent.rs
 create mode 100644 tests/headers/eval-value-dependent.hpp

diff --git a/src/clang.rs b/src/clang.rs
index e02d363fb9..b470e224ad 100644
--- a/src/clang.rs
+++ b/src/clang.rs
@@ -1875,27 +1875,25 @@ impl EvalResult {
             return None;
         }
 
-        // Clang has an internal assertion we can trigger if we try to evaluate
-        // a cursor containing a variadic template type reference. Triggering
-        // the assertion aborts the process, and we don't want that. Clang
-        // *also* doesn't expose any API for finding variadic vs non-variadic
-        // template type references, let alone whether a type referenced is a
-        // template type, instead they seem to show up as type references to an
-        // unexposed type. Our solution is to just flat out ban all
-        // `CXType_Unexposed` from evaluation.
-        let mut found_cant_eval = false;
-        cursor.visit(|c| if c.kind() == CXCursor_TypeRef &&
-            c.cur_type().kind() == CXType_Unexposed
+        // Work around https://bugs.llvm.org/show_bug.cgi?id=42532, see:
+        //  * https://github.com/rust-lang/rust-bindgen/issues/283
+        //  * https://github.com/rust-lang/rust-bindgen/issues/1590
         {
-            found_cant_eval = true;
-            CXChildVisit_Break
-        } else {
-            CXChildVisit_Recurse
-        });
-        if found_cant_eval {
-            return None;
-        }
+            let mut found_cant_eval = false;
+            cursor.visit(|c| {
+                if c.kind() == CXCursor_TypeRef &&
+                    c.cur_type().canonical_type().kind() == CXType_Unexposed {
+                    found_cant_eval = true;
+                    return CXChildVisit_Break;
+                }
+
+                CXChildVisit_Recurse
+            });
 
+            if found_cant_eval {
+                return None;
+            }
+        }
         Some(EvalResult {
             x: unsafe { clang_Cursor_Evaluate(cursor.x) },
         })
diff --git a/tests/expectations/tests/eval-value-dependent.rs b/tests/expectations/tests/eval-value-dependent.rs
new file mode 100644
index 0000000000..b290a2e6a1
--- /dev/null
+++ b/tests/expectations/tests/eval-value-dependent.rs
@@ -0,0 +1,15 @@
+/* automatically generated by rust-bindgen */
+
+#![allow(
+    dead_code,
+    non_snake_case,
+    non_camel_case_types,
+    non_upper_case_globals
+)]
+
+#[repr(C)]
+#[derive(Debug, Default, Copy, Clone)]
+pub struct e {
+    pub _address: u8,
+}
+pub type e_f<d> = d;
diff --git a/tests/headers/eval-value-dependent.hpp b/tests/headers/eval-value-dependent.hpp
new file mode 100644
index 0000000000..0f4dc6ab25
--- /dev/null
+++ b/tests/headers/eval-value-dependent.hpp
@@ -0,0 +1,6 @@
+// bindgen-flags: -- -std=c++11
+
+template <typename d> class e {
+  using f = d;
+  static const auto g = alignof(f);
+};