From 71fb88602f1be33cfd872baaaa3d39f5e35a6022 Mon Sep 17 00:00:00 2001
From: tocariimaa <tocariimaa@noreply.codeberg.org>
Date: Mon, 20 Jan 2025 19:30:22 -0300
Subject: [PATCH] move to nominal typing for some types

---
 compiler/sema.c | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/compiler/sema.c b/compiler/sema.c
index 11d0921..2dac8a3 100644
--- a/compiler/sema.c
+++ b/compiler/sema.c
@@ -56,8 +56,6 @@ typedef struct {
 static const Symbol InvalidSymbol = {.kind = SymInvalid};
 static const DataType *InvalidDataType = &(DataType){.kind = DtkInvalid};
 
-static DataTypeCheck
-datatype_struct_cmp(SemaCtx *sctx, DataType *s1, DataType *s2);
 static DataTypeCheck
 datatype_cmp(SemaCtx *sctx, DataType *dt1, DataType *dt2);
 static DataType *
@@ -414,7 +412,7 @@ sema_expr_list(SemaCtx *sctx, Vec(Ast *) exprs, Location loc)
 
 /* Structurally compare two structural data types. */
 static DataTypeCheck
-datatype_struct_cmp(SemaCtx *sctx, DataType *s1, DataType *s2)
+datatype_struct_can_cast(SemaCtx *sctx, DataType *s1, DataType *s2)
 {
 	compiler_assert(sctx->cm, s1->kind == DtkStruct && s2->kind == DtkStruct);
 	const DataTypeCompound *s1s = &s1->compound;
@@ -444,7 +442,7 @@ datatype_array_cmp(SemaCtx *sctx, DataType *a1, DataType *a2)
 }
 
 static DataTypeCheck
-datatype_proc_cmp(SemaCtx *sctx, DataType *pc1, DataType *pc2)
+datatype_proc_can_cast(SemaCtx *sctx, DataType *pc1, DataType *pc2)
 {
 	DataTypeCheck tchk = {.ok = true};
 
@@ -484,7 +482,7 @@ datatype_cmp(SemaCtx *sctx, DataType *dt1, DataType *dt2)
 	if (dt1 == nil || dt2 == nil)
 		return (DataTypeCheck){false, Sl("")};
 	/* TODO: return more information in case of a mismatch... */
-	if (dt1 == dt2) /* shallow */
+	if (dt1 == dt2) /* shallow comparison */
 		return (DataTypeCheck){.ok = true};
 	if (dt1->kind != dt2->kind)
 		return (DataTypeCheck){.ok = false};
@@ -492,16 +490,17 @@ datatype_cmp(SemaCtx *sctx, DataType *dt1, DataType *dt2)
 	switch (dt1->kind) {
 	case DtkBasic:
 		return datatype_basic_cmp(sctx, dt1, dt2);
-	case DtkStruct:
-	case DtkUnion:
-		return datatype_struct_cmp(sctx, dt1, dt2);
-	case DtkProc:
-		return datatype_proc_cmp(sctx, dt1, dt2);
 	case DtkArray:
 		return datatype_array_cmp(sctx, dt1, dt2);
+	/* Nominally typed, should have been catched by the shallow comparison above */
 	case DtkBool:
 	case DtkVoid:
-		return (DataTypeCheck){.ok = true};
+	case DtkStruct:
+	case DtkUnion:
+	case DtkProc:
+		break;
+	case DtkInvalid:
+		unreachable();
 	}
 	return (DataTypeCheck){.ok = false};
 }