diff --git a/src/compiler/compiler_internal.h b/src/compiler/compiler_internal.h
index e0ff7fdfc..e3ce2d559 100644
--- a/src/compiler/compiler_internal.h
+++ b/src/compiler/compiler_internal.h
@@ -2274,6 +2274,7 @@ void sema_error_prev_at(SourceSpan loc, const char *message, ...);
 void sema_verror_range(SourceSpan location, const char *message, va_list args);
 void sema_error(ParseContext *context, const char *message, ...);
 
+void sema_warning_at(SourceSpan loc, const char *message, ...);
 void sema_shadow_error(Decl *decl, Decl *old);
 bool sema_type_error_on_binop(Expr *expr);
 
diff --git a/src/compiler/diagnostics.c b/src/compiler/diagnostics.c
index 9eac16a3b..f3118013a 100644
--- a/src/compiler/diagnostics.c
+++ b/src/compiler/diagnostics.c
@@ -160,6 +160,15 @@ void sema_verror_range(SourceSpan location, const char *message, va_list args)
 	global_context.errors_found++;
 }
 
+void sema_warning_at(SourceSpan loc, const char *message, ...)
+{
+	if (global_context.suppress_errors) return;
+	va_list list;
+	va_start(list, message);
+	print_error(loc, str_vprintf(message, list), PRINT_TYPE_NOTE);
+	va_end(list);
+}
+
 
 void sema_error_at(SourceSpan loc, const char *message, ...)
 {
diff --git a/src/compiler/sema_decls.c b/src/compiler/sema_decls.c
index e1cbcebc4..d9a74bcbe 100644
--- a/src/compiler/sema_decls.c
+++ b/src/compiler/sema_decls.c
@@ -1547,7 +1547,7 @@ static bool sema_analyse_attribute(SemaContext *context, Decl *decl, Attr *attr,
 				}
 			}
 			decl->is_deprecated = true;
-			break;
+			return true;
 		case ATTRIBUTE_WINMAIN:
 			if (decl->name != kw_main)
 			{
@@ -2705,8 +2705,15 @@ bool sema_analyse_var_decl(SemaContext *context, Decl *decl, bool local)
 
 	if (!sema_resolve_type_info_maybe_inferred(context, decl->var.type_info, decl->var.init_expr != NULL)) return decl_poison(decl);
 
-	decl->type = decl->var.type_info->type;
+	Type *type = decl->type = decl->var.type_info->type;
 	if (!sema_analyse_decl_type(context, decl->type, decl->var.type_info->span)) return decl_poison(decl);
+
+	if (type) type = type_no_optional(type);
+	if (type_is_user_defined(type))
+	{
+		sema_display_deprecated_warning_on_use(context, type->decl, decl->var.type_info->span);
+	}
+
 	bool is_static = decl->var.is_static;
 	if (is_static && context->call_env.pure)
 	{
@@ -2783,7 +2790,7 @@ bool sema_analyse_var_decl(SemaContext *context, Decl *decl, bool local)
 			init_expr->const_expr.is_hex = false;
 		}
 	}
-	EXIT_OK:
+	EXIT_OK:;
 	if (!decl->alignment)
 	{
 		if (!sema_set_alloca_alignment(context, decl->type, &decl->alignment)) return false;
@@ -3155,8 +3162,28 @@ bool sema_analyse_decl(SemaContext *context, Decl *decl)
 	}
 	decl->resolve_status = RESOLVE_DONE;
 	sema_context_destroy(&temp_context);
+
 	return true;
 FAILED:
 	sema_context_destroy(&temp_context);
 	return decl_poison(decl);
 }
+
+void sema_display_deprecated_warning_on_use(SemaContext *context, Decl *decl, SourceSpan span)
+{
+	if (!decl->is_deprecated) return;
+	decl->is_deprecated = false;
+	FOREACH_BEGIN(Attr *attr, decl->attributes)
+		if (attr->attr_kind == ATTRIBUTE_DEPRECATED)
+		{
+			if (attr->exprs)
+			{
+				const char *comment_string = attr->exprs[0]->const_expr.string.chars;
+				sema_warning_at(span, "'%s' is deprecated: %s.", decl->name, comment_string);
+				return;
+			}
+			break;
+		}
+	FOREACH_END();
+	sema_warning_at(span, "'%s' is deprecated.", decl->name);
+}
diff --git a/src/compiler/sema_expr.c b/src/compiler/sema_expr.c
index a18d0ebe4..b2f946a4f 100644
--- a/src/compiler/sema_expr.c
+++ b/src/compiler/sema_expr.c
@@ -837,6 +837,8 @@ static inline bool sema_expr_analyse_identifier(SemaContext *context, Type *to,
 	{
 		if (!sema_analyse_decl(context, decl)) return decl_poison(decl);
 	}
+	sema_display_deprecated_warning_on_use(context, decl, expr->span);
+
 	unit_register_external_symbol(context->compilation_unit, decl);
 	if (decl->decl_kind == DECL_VAR)
 	{
@@ -1516,6 +1518,7 @@ static inline bool sema_call_analyse_func_invocation(SemaContext *context, Type
 	}
 
 	bool is_unused = expr->call_expr.result_unused;
+
 	if (!sema_call_analyse_invocation(context, expr, callee, &optional)) return false;
 
 	Type *rtype = type->function.prototype->rtype;
@@ -1653,6 +1656,8 @@ static inline bool sema_expr_analyse_func_call(SemaContext *context, Expr *expr,
 		SEMA_ERROR(expr, "@test functions may not be directly called.");
 		return false;
 	}
+	sema_display_deprecated_warning_on_use(context, decl, expr->span);
+
 	return sema_call_analyse_func_invocation(context,
 	                                         decl->type,
 	                                         expr,
@@ -1672,6 +1677,8 @@ bool sema_expr_analyse_macro_call(SemaContext *context, Expr *call_expr, Expr *s
 		SEMA_ERROR(call_expr, "Failure evaluating macro, max call depth reached.");
 		return false;
 	}
+	sema_display_deprecated_warning_on_use(context, decl, call_expr->span);
+
 	copy_begin();
 	Decl **params = copy_decl_list_macro(decl->func_decl.signature.params);
 	Ast *body = copy_ast_macro(astptr(decl->func_decl.body));
diff --git a/src/compiler/sema_internal.h b/src/compiler/sema_internal.h
index 5a8dbfc42..b2083a67e 100644
--- a/src/compiler/sema_internal.h
+++ b/src/compiler/sema_internal.h
@@ -104,6 +104,7 @@ void cast_to_max_bit_size(SemaContext *context, Expr *left, Expr *right, Type *l
 bool cast_decay_array_pointers(SemaContext *context, Expr *expr);
 INLINE bool sema_set_abi_alignment(SemaContext *context, Type *type, AlignSize *result);
 INLINE bool sema_set_alloca_alignment(SemaContext *context, Type *type, AlignSize *result);
+void sema_display_deprecated_warning_on_use(SemaContext *context, Decl *decl, SourceSpan use);
 
 INLINE bool sema_set_abi_alignment(SemaContext *context, Type *type, AlignSize *result)
 {
diff --git a/src/version.h b/src/version.h
index 384c24bf0..71dfa4064 100644
--- a/src/version.h
+++ b/src/version.h
@@ -1 +1 @@
-#define COMPILER_VERSION "0.4.86"
\ No newline at end of file
+#define COMPILER_VERSION "0.4.87"
\ No newline at end of file