From db4a9d6b590b02a9d666acb0cae8c0009c385e5e Mon Sep 17 00:00:00 2001
From: Delyan Angelov <delian66@gmail.com>
Date: Sat, 4 Jul 2020 20:58:10 +0300
Subject: [PATCH] checker: stricter check for function type signatures

---
 vlib/v/checker/check_types.v | 54 ++++++++++++++++++++++++++----------
 vlib/v/checker/checker.v     |  1 +
 vlib/v/table/atypes.v        |  5 +++-
 3 files changed, 44 insertions(+), 16 deletions(-)

diff --git a/vlib/v/checker/check_types.v b/vlib/v/checker/check_types.v
index d63b48af09..3736530158 100644
--- a/vlib/v/checker/check_types.v
+++ b/vlib/v/checker/check_types.v
@@ -8,6 +8,9 @@ import v.token
 import v.ast
 
 pub fn (c &Checker) check_basic(got, expected table.Type) bool {
+	if got == expected {
+		return true
+	}
 	t := c.table
 	got_idx := t.unalias_num_type(got).idx()
 	exp_idx := t.unalias_num_type(expected).idx()
@@ -117,25 +120,43 @@ pub fn (c &Checker) check_basic(got, expected table.Type) bool {
 	}
 	// fn type
 	if got_type_sym.kind == .function && exp_type_sym.kind == .function {
-		got_info := got_type_sym.info as table.FnType
-		exp_info := exp_type_sym.info as table.FnType
-		got_fn := got_info.func
-		exp_fn := exp_info.func
-		// we are using check() to compare return type & args as they might include
-		// functions themselves. TODO: optimize, only use check() when needed
-		if got_fn.args.len == exp_fn.args.len && c.check_basic(got_fn.return_type, exp_fn.return_type) {
-			for i, got_arg in got_fn.args {
-				exp_arg := exp_fn.args[i]
-				if !c.check_basic(got_arg.typ, exp_arg.typ) {
-					return false
-				}
-			}
-			return true
-		}
+		return c.check_matching_function_symbols(got_type_sym, exp_type_sym)
 	}
 	return false
 }
 
+pub fn (c &Checker) check_matching_function_symbols(got_type_sym &table.TypeSymbol, exp_type_sym &table.TypeSymbol) bool {
+	got_info := got_type_sym.info as table.FnType
+	exp_info := exp_type_sym.info as table.FnType
+	got_fn := got_info.func
+	exp_fn := exp_info.func
+	// we are using check() to compare return type & args as they might include
+	// functions themselves. TODO: optimize, only use check() when needed
+	if got_fn.args.len != exp_fn.args.len {
+		return false
+	}
+	if !c.check_basic(got_fn.return_type, exp_fn.return_type) {
+		return false
+	}
+	for i, got_arg in got_fn.args {
+		exp_arg := exp_fn.args[i]
+		exp_arg_is_ptr := exp_arg.typ.is_ptr() || exp_arg.typ.is_pointer()
+		got_arg_is_ptr := got_arg.typ.is_ptr() || got_arg.typ.is_pointer()
+		if exp_arg_is_ptr != got_arg_is_ptr {
+			$if debug_matching_function_symbols ? {
+				exp_arg_pointedness := if exp_arg_is_ptr { 'a pointer' } else { 'NOT a pointer' }
+				got_arg_pointedness := if got_arg_is_ptr { 'a pointer' } else { 'NOT a pointer' }
+				eprintln('`$exp_fn.name` expected fn argument: `$exp_arg.name` is $exp_arg_pointedness, but `$got_fn.name` actual fn argument: `$got_arg.name` is $got_arg_pointedness')
+			}
+			return false
+		}
+		if !c.check_basic(got_arg.typ, exp_arg.typ) {
+			return false
+		}
+	}
+	return true
+}
+
 [inline]
 fn (c &Checker) check_shift(left_type, right_type table.Type, left_pos, right_pos token.Position) table.Type {
 	if !left_type.is_int() {
@@ -215,6 +236,9 @@ fn (c &Checker) promote_num(left_type, right_type table.Type) table.Type {
 
 // TODO: promote(), check_types(), symmetric_check() and check() overlap - should be rearranged
 pub fn (c &Checker) check_types(got, expected table.Type) bool {
+	if got == expected {
+		return true
+	}
 	exp_idx := expected.idx()
 	got_idx := got.idx()
 	if exp_idx == got_idx {
diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index e3b4cb6953..badcde628e 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -1180,6 +1180,7 @@ pub fn (mut c Checker) call_fn(mut call_expr ast.CallExpr) table.Type {
 			return true
 		}
 		*/
+
 		if !c.check_types(typ, arg.typ) {
 			// str method, allow type with str method if fn arg is string
 			if arg_typ_sym.kind == .string && typ_sym.has_method('str') {
diff --git a/vlib/v/table/atypes.v b/vlib/v/table/atypes.v
index c186db3c53..00a615e593 100644
--- a/vlib/v/table/atypes.v
+++ b/vlib/v/table/atypes.v
@@ -641,7 +641,10 @@ pub fn (k Kind) str() string {
 		.alias { 'alias' }
 		.enum_ { 'enum' }
 		.any { 'any' }
-		else { 'unknown' }
+		.function { 'function' }
+		.interface_ { 'interface' }
+		.ustring { 'ustring' }
+		.generic_struct_inst { 'generic_struct_inst' }
 	}
 	return k_str
 }