Fix bug when enum matched multiple types

If an enum matched a pattern for rustified enum and constified module
enum, then rust code would fail to compile with "ambiguous associated
type" error. We fix the error by giving constified module enum "higher
precedence".

Fixes issue rust-lang#1198

Author: tmfink

src/codegen/mod.rs

@@ -2461,12 +2461,14 @@ impl CodeGenerator for Enum {
             }
         };
 
+        // ModuleConsts has higher precedence before Rust in order to avoid problems with
+        // overlapping match patterns
         let variation = if self.is_bitfield(ctx, item) {
             EnumVariation::Bitfield
-        } else if self.is_rustified_enum(ctx, item) {
-            EnumVariation::Rust
         } else if self.is_constified_enum_module(ctx, item) {
             EnumVariation::ModuleConsts
+        } else if self.is_rustified_enum(ctx, item) {
+            EnumVariation::Rust
         } else {
             // We generate consts by default
             EnumVariation::Consts

tests/expectations/tests/libclang-3.9/issue-1198-alias-rust-const-mod-enum.rs

@@ -0,0 +1,16 @@
+/* automatically generated by rust-bindgen */
+
+#![allow(dead_code, non_snake_case, non_camel_case_types, non_upper_case_globals)]
+
+pub mod MyDupeEnum {
+    pub type Type = u32;
+    pub const A: Type = 0;
+    pub const A_alias: Type = 0;
+    pub const B: Type = 1;
+}
+pub mod MyOtherDupeEnum {
+    pub type Type = u32;
+    pub const C: Type = 0;
+    pub const C_alias: Type = 0;
+    pub const D: Type = 1;
+}

tests/expectations/tests/libclang-3.9/issue-1198-alias-rust-enum.rs

@@ -0,0 +1,18 @@
+/* automatically generated by rust-bindgen */
+
+#![allow(dead_code, non_snake_case, non_camel_case_types, non_upper_case_globals)]
+
+pub const MyDupeEnum_A_alias: MyDupeEnum = MyDupeEnum::A;
+#[repr(u32)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+pub enum MyDupeEnum {
+    A = 0,
+    B = 1,
+}
+pub const MyOtherDupeEnum_C_alias: MyOtherDupeEnum = MyOtherDupeEnum::C;
+#[repr(u32)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+pub enum MyOtherDupeEnum {
+    C = 0,
+    D = 1,
+}

tests/headers/issue-1198-alias-rust-const-mod-enum.h

@@ -0,0 +1,13 @@
+// bindgen-flags: --rustified-enum '.*' --constified-enum-module '.*'
+
+typedef enum MyDupeEnum {
+	A = 0,
+	A_alias = 0,
+	B,
+} MyDupeEnum;
+
+enum MyOtherDupeEnum {
+	C = 0,
+	C_alias = 0,
+	D,
+};

tests/headers/issue-1198-alias-rust-enum.h

@@ -0,0 +1,14 @@
+// bindgen-flags: --rustified-enum '.*'
+
+
+typedef enum MyDupeEnum {
+	A = 0,
+	A_alias = 0,
+	B,
+} MyDupeEnum;
+
+enum MyOtherDupeEnum {
+	C = 0,
+	C_alias = 0,
+	D,
+};