Improve error message on `using` with procedure parameters #568

4 files changed, 15 insertions, 6 deletions

diff --git a/src/check_decl.cpp b/src/check_decl.cpp
index 0e669e473..ece38e84f 100644
--- a/src/check_decl.cpp
+++ b/src/check_decl.cpp
@@ -1207,7 +1207,7 @@ void check_proc_body(CheckerContext *ctx_, Token token, DeclInfo *decl, Type *ty
 	}
 
 
-	bool where_clause_ok = evaluate_where_clauses(ctx, decl->scope, &decl->proc_lit->ProcLit.where_clauses, true);
+	bool where_clause_ok = evaluate_where_clauses(ctx, nullptr, decl->scope, &decl->proc_lit->ProcLit.where_clauses, true);
 	if (!where_clause_ok) {
 		// NOTE(bill, 2019-08-31): Don't check the body as the where clauses failed
 		return;
diff --git a/src/check_expr.cpp b/src/check_expr.cpp
index d98b3d0d6..069605035 100644
--- a/src/check_expr.cpp
+++ b/src/check_expr.cpp
@@ -6300,7 +6300,7 @@ Entity **populate_proc_parameter_list(CheckerContext *c, Type *proc_type, isize
 }
 
 
-bool evaluate_where_clauses(CheckerContext *ctx, Scope *scope, Array<Ast *> *clauses, bool print_err) {
+bool evaluate_where_clauses(CheckerContext *ctx, Ast *call_expr, Scope *scope, Array<Ast *> *clauses, bool print_err) {
 	if (clauses != nullptr) {
 		for_array(i, *clauses) {
 			Ast *clause = (*clauses)[i];
@@ -6308,9 +6308,11 @@ bool evaluate_where_clauses(CheckerContext *ctx, Scope *scope, Array<Ast *> *cla
 			check_expr(ctx, &o, clause);
 			if (o.mode != Addressing_Constant) {
 				if (print_err) error(clause, "'where' clauses expect a constant boolean evaluation");
+				if (print_err && call_expr) error(call_expr, "at caller location");
 				return false;
 			} else if (o.value.kind != ExactValue_Bool) {
 				if (print_err) error(clause, "'where' clauses expect a constant boolean evaluation");
+				if (print_err && call_expr) error(call_expr, "at caller location");
 				return false;
 			} else if (!o.value.value_bool) {
 				if (print_err) {
@@ -6352,6 +6354,7 @@ bool evaluate_where_clauses(CheckerContext *ctx, Scope *scope, Array<Ast *> *cla
 						}
 					}
 
+					if (call_expr) error(call_expr, "at caller location");
 				}
 				return false;
 			}
@@ -6617,7 +6620,7 @@ CallArgumentData check_call_arguments(CheckerContext *c, Operand *operand, Type
 					ctx.curr_proc_sig  = e->type;
 
 					GB_ASSERT(decl->proc_lit->kind == Ast_ProcLit);
-					if (!evaluate_where_clauses(&ctx, decl->scope, &decl->proc_lit->ProcLit.where_clauses, false)) {
+					if (!evaluate_where_clauses(&ctx, operand->expr, decl->scope, &decl->proc_lit->ProcLit.where_clauses, false)) {
 						continue;
 					}
 				}
diff --git a/src/check_stmt.cpp b/src/check_stmt.cpp
index c365dca84..bef1919e4 100644
--- a/src/check_stmt.cpp
+++ b/src/check_stmt.cpp
@@ -314,7 +314,11 @@ Type *check_assignment_variable(CheckerContext *ctx, Operand *lhs, Operand *rhs)
 
 		gbString str = expr_to_string(lhs->expr);
 		if (e != nullptr && e->flags & EntityFlag_Param) {
-			error(lhs->expr, "Cannot assign to '%s' which is a procedure parameter", str);
+			if (e->flags & EntityFlag_Using) {
+				error(lhs->expr, "Cannot assign to '%s' which is from a 'using' procedure parameter", str);
+			} else {
+				error(lhs->expr, "Cannot assign to '%s' which is a procedure parameter", str);
+			}
 		} else {
 			error(lhs->expr, "Cannot assign to '%s'", str);
 		}
@@ -497,6 +501,8 @@ bool check_using_stmt_entity(CheckerContext *ctx, AstUsingStmt *us, Ast *expr, b
 				Entity *f = found->elements.entries[i].value;
 				if (f->kind == Entity_Variable) {
 					Entity *uvar = alloc_entity_using_variable(e, f->token, f->type, expr);
+					if (e->flags & EntityFlag_Value) uvar->flags |= EntityFlag_Value;
+					if (e->flags & EntityFlag_Param) uvar->flags |= EntityFlag_Param;
 					Entity *prev = scope_insert(ctx->scope, uvar);
 					if (prev != nullptr) {
 						gbString expr_str = expr_to_string(expr);
diff --git a/src/check_type.cpp b/src/check_type.cpp
index f21ffc956..97b9985c8 100644
--- a/src/check_type.cpp
+++ b/src/check_type.cpp
@@ -527,7 +527,7 @@ void check_struct_type(CheckerContext *ctx, Type *struct_type, Ast *node, Array<
 		if (st->where_clauses.count > 0 && st->polymorphic_params == nullptr) {
 			error(st->where_clauses[0], "'where' clauses can only be used on structures with polymorphic parameters");
 		} else {
-			bool where_clause_ok = evaluate_where_clauses(ctx, ctx->scope, &st->where_clauses, true);
+			bool where_clause_ok = evaluate_where_clauses(ctx, node, ctx->scope, &st->where_clauses, true);
 		}
 		check_struct_fields(ctx, node, &struct_type->Struct.fields, &struct_type->Struct.tags, st->fields, min_field_count, struct_type, context);
 	}
@@ -714,7 +714,7 @@ void check_union_type(CheckerContext *ctx, Type *union_type, Ast *node, Array<Op
 	if (ut->where_clauses.count > 0 && ut->polymorphic_params == nullptr) {
 		error(ut->where_clauses[0], "'where' clauses can only be used on unions with polymorphic parameters");
 	} else {
-		bool where_clause_ok = evaluate_where_clauses(ctx, ctx->scope, &ut->where_clauses, true);
+		bool where_clause_ok = evaluate_where_clauses(ctx, node, ctx->scope, &ut->where_clauses, true);
 	}