diff --git a/src/aro/Diagnostics/messages.def b/src/aro/Diagnostics/messages.def
index 89faf02e..5d242d32 100644
--- a/src/aro/Diagnostics/messages.def
+++ b/src/aro/Diagnostics/messages.def
@@ -2482,3 +2482,8 @@ attribute_todo
     .msg = "TODO: implement '{s}' attribute for {s}"
     .extra = .attribute_todo
     .kind = .@"error"
+
+invalid_type_underlying_enum
+    .msg = "non-integral type '{s}' is an invalid underlying type"
+    .extra = .str
+    .kind = .@"error"
diff --git a/src/aro/Parser.zig b/src/aro/Parser.zig
index c395ee2a..ef39f075 100644
--- a/src/aro/Parser.zig
+++ b/src/aro/Parser.zig
@@ -2478,7 +2478,8 @@ fn enumSpec(p: *Parser) Error!Type {
 
     const maybe_ident = try p.eatIdentifier();
     const fixed_ty = if (p.eatToken(.colon)) |colon| fixed: {
-        const fixed = (try p.typeName()) orelse {
+        const ty_start = p.tok_i;
+        const fixed = (try p.specQual()) orelse {
             if (p.record.kind != .invalid) {
                 // This is a bit field.
                 p.tok_i -= 1;
@@ -2488,6 +2489,12 @@ fn enumSpec(p: *Parser) Error!Type {
             try p.errTok(.enum_fixed, colon);
             break :fixed null;
         };
+
+        if (!fixed.isInt() or fixed.is(.@"enum")) {
+            try p.errStr(.invalid_type_underlying_enum, ty_start, try p.typeStr(fixed));
+            break :fixed Type.int;
+        }
+
         try p.errTok(.enum_fixed, colon);
         break :fixed fixed;
     } else null;
diff --git a/test/cases/enum fixed.c b/test/cases/enum fixed.c
index 5c9dd94e..6fa58d4e 100644
--- a/test/cases/enum fixed.c	
+++ b/test/cases/enum fixed.c	
@@ -71,6 +71,34 @@ void pointers(void) {
     enum Incomplete *i2 = &y;
 }
 
+typedef struct BackingStruct {
+   int x;
+} BackingStruct;
+
+typedef enum BackingEnum : int {
+   B0,
+} BackingEnum;
+
+enum Bad1: BackingStruct {
+    B1,
+};
+
+enum Bad2: BackingEnum {
+    B2,
+};
+
+enum Bad3: unsigned * {
+    B3,
+};
+
+void more_pointers(void) {
+    unsigned y;
+
+    enum SignedEnum: int *p = &y;
+    enum UnsignedEnum: unsigned *p2 = &y;
+    enum CharEnum: char signed *p3 = &y;
+}
+
 #define EXPECTED_ERRORS "enum fixed.c:2:7: warning: enumeration types with a fixed underlying type are a Clang extension [-Wfixed-enum-extension]" \
     "enum fixed.c:4:6: error: enumeration previously declared with fixed underlying type" \
     "enum fixed.c:2:6: note: previous definition is here" \
@@ -84,4 +112,9 @@ void pointers(void) {
     "enum fixed.c:67:25: warning: incompatible pointer types initializing 'enum Unsigned: unsigned int *' from incompatible type 'int *' [-Wincompatible-pointer-types]" \
     "enum fixed.c:70:27: warning: incompatible pointer types initializing 'enum Incomplete *' from incompatible type 'int *' [-Wincompatible-pointer-types]" \
     "enum fixed.c:71:27: warning: incompatible pointer types initializing 'enum Incomplete *' from incompatible type 'unsigned int *' [-Wincompatible-pointer-types]" \
+    "enum fixed.c:82:12: error: non-integral type 'struct BackingStruct' is an invalid underlying type" \
+    "enum fixed.c:86:12: error: non-integral type 'enum BackingEnum: int' is an invalid underlying type" \
+    "enum fixed.c:90:23: error: expected identifier or '('" \
+    "enum fixed.c:97:31: warning: incompatible pointer types initializing 'enum SignedEnum: int *' from incompatible type 'unsigned int *' converts between pointers to integer types with different sign [-Wpointer-sign]" \
+    "enum fixed.c:99:38: warning: incompatible pointer types initializing 'enum CharEnum: signed char *' from incompatible type 'unsigned int *' [-Wincompatible-pointer-types]" \