From a00b17bf71706240587c3d5bdcd227f56af7a92a Mon Sep 17 00:00:00 2001
From: Bill Currie <bill@taniwha.org>
Date: Wed, 21 Aug 2024 08:23:12 +0900
Subject: [PATCH] [qfcc] Check declarator type chains

Arrays of functions or functions that return arrays or functions aren't
valid. While working on how to get generics in properly, I finally
understood what's going on with function types in the specifier, and I
think I'll be able to sort out function pointers vs prototypes, too.
---
 ruamoko/lib/types.r          |  2 +-
 tools/qfcc/source/qc-parse.y | 31 ++++++++++++++++++++++++++++++-
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/ruamoko/lib/types.r b/ruamoko/lib/types.r
index facf9ba1d..a2ef79dde 100644
--- a/ruamoko/lib/types.r
+++ b/ruamoko/lib/types.r
@@ -16,7 +16,7 @@ string ty_meta_name[10] = {
 
 //FIXME use pr_type_names.h, but need to fix unsigned, and add missing types
 #define field .int
-#define func void()(void)
+#define func @function(void)
 #define ptr void *
 #define uint unsigned
 #define ulong unsigned long
diff --git a/tools/qfcc/source/qc-parse.y b/tools/qfcc/source/qc-parse.y
index 076d82b04..e6277eda8 100644
--- a/tools/qfcc/source/qc-parse.y
+++ b/tools/qfcc/source/qc-parse.y
@@ -421,6 +421,17 @@ function_spec (specifier_t spec, param_t *params)
 		spec = default_type (spec, spec.sym);
 	}
 	spec.sym->params = params;
+	if (spec.sym->type) {
+		if (is_func (spec.sym->type)) {
+			error (0, "'%s' declared as a function returning a function",
+				   spec.sym->name);
+		} else if (is_array (spec.sym->type)) {
+			error (0, "declaration of '%s' as array of functions",
+				   spec.sym->name);
+		} else if (!is_ptr (spec.sym->type) && !is_field (spec.sym->type)) {
+			internal_error (0, "unexpected type");
+		}
+	}
 	spec.sym->type = append_type (spec.sym->type, parse_params (0, params));
 	spec.is_function = true; //FIXME do proper void(*)() -> ev_func
 	spec.is_generic = generic_scope;
@@ -433,6 +444,16 @@ static specifier_t
 array_spec (specifier_t spec, unsigned size)
 {
 	spec = default_type (spec, spec.sym);
+	if (spec.sym->type) {
+		if (is_func (spec.sym->type)) {
+			error (0, "'%s' declared as function returning an array",
+				   spec.sym->name);
+		} else if (!is_ptr (spec.sym->type)
+				   && !is_array (spec.sym->type)
+				   && !is_field (spec.sym->type)) {
+			internal_error (0, "unexpected type");
+	   }
+	}
 	spec.sym->type = append_type (spec.sym->type, array_type (0, size));
 	return spec;
 }
@@ -440,6 +461,14 @@ array_spec (specifier_t spec, unsigned size)
 static specifier_t
 pointer_spec (specifier_t quals, specifier_t spec)
 {
+	if (spec.sym->type) {
+		if (!is_func (spec.sym->type)
+			&& !is_ptr (spec.sym->type)
+			&& !is_array (spec.sym->type)
+			&& !is_field (spec.sym->type)) {
+			internal_error (0, "unexpected type");
+	   }
+	}
 	spec.sym->type = append_type (spec.sym->type, pointer_type (0));
 	return spec;
 }
@@ -688,7 +717,7 @@ qc_param_list
 	;
 // quakec function parameters cannot use a typedef as the return type
 // in the first parameter (really, they should't use any as standard quakec
-// doesn't support typedef, but that seems overly restrictive), howevery,
+// doesn't support typedef, but that seems overly restrictive), however,
 // they can stil use a typedef first parameter. This is due to grammar issues
 qc_first_param
 	: typespec identifier