diff --git a/vlib/compiler/cgen.v b/vlib/compiler/cgen.v
index bc62dde7f0..239eb0222b 100644
--- a/vlib/compiler/cgen.v
+++ b/vlib/compiler/cgen.v
@@ -5,6 +5,7 @@
 module compiler
 
 import os
+import strings
 
 struct CGen {
 	out          os.File
@@ -387,3 +388,32 @@ fn sort_structs(types []Type) []Type {
 	}
 	return types_sorted
 }
+
+fn (v &V) interface_table() string {
+       mut sb := strings.new_builder(100)
+       for _, t in v.table.typesmap {
+               if t.cat != .interface_ {
+                       continue
+               }
+               mut methods := ''
+               for i, gen_type in t.gen_types {
+                       methods += '{'
+                       for i, method in t.methods {
+					       // Cat_speak
+                               methods += '${gen_type}_${method.name}'
+                               if i < t.methods.len - 1 {
+                                       methods += ', '
+                               }
+                       }
+                       methods += '}, '
+                       // Speaker_Cat_index = 0
+                       sb.writeln('int _${t.name}_${gen_type}_index = $i;')
+               }
+               sb.writeln('void* (* ${t.name}_name_table[][$t.methods.len]) = ' +
+'{ $methods }; ')
+               continue
+       }
+       return sb.str()
+}
+
+
diff --git a/vlib/compiler/fn.v b/vlib/compiler/fn.v
index eda4a0030e..dfdf6308fb 100644
--- a/vlib/compiler/fn.v
+++ b/vlib/compiler/fn.v
@@ -12,8 +12,7 @@ const (
 	MaxLocalVars = 50
 )
 
-pub
-struct Fn {
+pub struct Fn {
 	// addr int
 pub:
 mut:
@@ -560,7 +559,7 @@ fn (p mut Parser) skip_fn_body() {
 	}
 }
 
-fn (p Parser) get_linkage_prefix() string {
+fn (p &Parser) get_linkage_prefix() string {
 	return if p.pref.ccompiler == 'msvc' && p.attr == 'live' && p.pref.is_so {
 		'__declspec(dllexport) '
 	} else if p.attr == 'inline' {
@@ -718,6 +717,27 @@ fn (p mut Parser) fn_call(f mut Fn, method_ph int, receiver_var, receiver_type s
 	// we need to preappend "method(receiver, ...)"
 	if f.is_method {
 		receiver := f.args.first()
+		if receiver.typ.ends_with('er') {
+			// I absolutely love this syntax
+			// `s.speak()` =>
+			// `((void (*)())(Speaker_name_table[s._interface_idx][1]))(s._object);
+			// where `1` refers to the speak method, since it's the second method
+			// of the Speaker interface
+			t := p.table.find_type(receiver.typ)
+			if t.cat == .interface_ {
+				// Find the index of the method
+				mut idx := 0
+				for i, method in t.methods {
+					if method.name == f.name {
+						idx = i
+					}	
+				}	
+				p.cgen.resetln('')
+				var := p.expr_var.name
+				iname := f.args[0].typ // Speaker
+				p.gen('((void (*)())(${iname}_name_table[${var}._interface_idx][$idx]))(${var}._object)')
+			}
+		}
 		//println('r=$receiver.typ RT=$receiver_type')
 		if receiver.is_mut && !p.expr_var.is_mut {
 			//println('$method_call  recv=$receiver.name recv_mut=$receiver.is_mut')
@@ -747,7 +767,9 @@ fn (p mut Parser) fn_call(f mut Fn, method_ph int, receiver_var, receiver_type s
 		// println('calling inst $f.name: $p.cgen.cur_line')
 	}
 
-	p.gen(')')
+	//if !is_interface {
+		p.gen(')')
+	//}
 	p.calling_c = false
 	if is_comptime_define {
 		p.cgen.nogen = false
@@ -757,16 +779,16 @@ fn (p mut Parser) fn_call(f mut Fn, method_ph int, receiver_var, receiver_type s
 }
 
 // for declaration
-// return an updated Fn object with args[] field set
+// update the Fn object's args[]
 fn (p mut Parser) fn_args(f mut Fn) {
 	p.check(.lpar)
 	defer { p.check(.rpar) }
 	if f.is_interface {
-		int_arg := Var {
+		interface_arg := Var {
 			typ: f.receiver_typ
 			token_idx: p.cur_tok_index()
 		}
-		f.args << int_arg
+		f.args << interface_arg
 	}
 	// `(int, string, int)`
 	// Just register fn arg types
@@ -829,7 +851,7 @@ fn (p mut Parser) fn_args(f mut Fn) {
 		p.check_and_register_used_imported_type(typ)
 		if is_mut && is_primitive_type(typ) {
 			p.error('mutable arguments are only allowed for arrays, maps, and structs.' +
-			'\nreturn values instead: `foo(n mut int)` => `foo(n int) int`')
+			'\nreturn values instead: `fn foo(n mut int) {` => `fn foo(n int) int {`')
 		}
 		for name in names {
 			if is_mut {
@@ -916,8 +938,7 @@ fn (p mut Parser) fn_call_args(f mut Fn) {
 		ph := p.cgen.add_placeholder()
 		// `)` here means that not enough args were provided
 		if p.tok == .rpar {
-			str_args := f.str_args(p.table)// TODO this is C args
-			p.error('not enough arguments in call to `$f.name ($str_args)`')
+			p.error('not enough arguments in call to `${f.str_for_error()}`')
 		}
 		// If `arg` is mutable, the caller needs to provide `mut`:
 		// `mut numbers := [1,2,3]; reverse(mut numbers);`
@@ -951,6 +972,21 @@ fn (p mut Parser) fn_call_args(f mut Fn) {
 			p.gen('/*YY f=$f.name arg=$arg.name is_moved=$arg.is_moved*/string_clone(')
 		}
 		mut typ := p.bool_expression()
+		// Register an interface type usage:
+		// fn run(r Animal) { ... }
+		// `run(dog)` adds `Dog` to the `Animal` interface.
+		// This is needed to generate an interface table.
+		if arg.typ.ends_with('er') {
+		        t := p.table.find_type(arg.typ)
+		        if t.cat == .interface_ {
+		                // perform((Speaker) { ._object = &dog,
+		                //     _interface_idx = _Speaker_Dog_index })
+		                p.cgen.set_placeholder(ph, '($arg.typ) { ._object = &')
+		                p.gen(', ._interface_idx = _${arg.typ}_${typ}_index} /* i. arg*/')
+		                p.table.add_gen_type(arg.typ, typ)
+		        }
+		}
+
 		if clone {
 			p.gen(')')
 		}
@@ -1077,19 +1113,19 @@ fn (p mut Parser) fn_call_args(f mut Fn) {
 		}
 		else if is_interface {
 			if !got_ptr {
-				p.cgen.set_placeholder(ph, '&')
+				//p.cgen.set_placeholder(ph, '&')
 			}
 			// Pass all interface methods
-			interface_type := p.table.find_type(arg.typ)
-			for method in interface_type.methods {
-				p.gen(', ${typ}_${method.name} ')
-			}
+			//interface_type := p.table.find_type(arg.typ)
+			//for method in interface_type.methods {
+				//p.gen(', ${typ}_${method.name} ')
+			//}
 		}
 		// Check for commas
 		if i < f.args.len - 1 {
 			// Handle 0 args passed to varargs
 			if p.tok != .comma && !f.is_variadic {
-				p.error('wrong number of arguments for $i,$arg.name fn `$f.name`: expected $f.args.len, but got less')
+				p.error('wrong number of arguments in call to `${f.str_for_error()}`')
 			}
 			if p.tok == .comma && (!f.is_variadic || (f.is_variadic && i < f.args.len-2 )) {
 				p.check(.comma)
@@ -1103,7 +1139,7 @@ fn (p mut Parser) fn_call_args(f mut Fn) {
 		saved_args << varg_type
 	}
 	if p.tok == .comma {
-		p.error('wrong number of arguments for fn `$f.name`: expected $f.args.len, but got more')
+		p.error('wrong number of arguments in call to `${f.str_for_error()}`')
 	}
 	p.check(.rpar)
 	if f.is_generic {
@@ -1223,8 +1259,8 @@ fn (p mut Parser) replace_type_params(f &Fn, ti TypeInst) []string {
 fn (p mut Parser) register_vargs_stuct(typ string, len int) string {
 	vargs_struct := 'varg_$typ'
 	varg_type := Type{
-		cat: .struct_,
-		name: vargs_struct,
+		cat: .struct_
+		name: vargs_struct
 		mod: p.mod
 	}
 	mut varg_len := len
@@ -1462,6 +1498,7 @@ fn (f &Fn) str_args(table &Table) string {
 		// to all methods:
 		// fn handle(r Runner) { =>
 		// void handle(void *r, void (*Runner_run)(void*)) {
+			/*
 		if table.is_interface(arg.typ) {
 			// First the object (same name as the interface argument)
 			s += ' void* $arg.name'
@@ -1477,7 +1514,8 @@ fn (f &Fn) str_args(table &Table) string {
 				s += ')'
 			}
 		}
-		else if arg.typ.starts_with('varg_') {
+		*/
+		if arg.typ.starts_with('varg_') {
 			s += '$arg.typ *$arg.name'
 		}
 		else {
@@ -1519,11 +1557,31 @@ fn (fns []Fn) contains(f Fn) bool {
 	return false
 }
 
-pub fn (f Fn) v_fn_module() string {
+pub fn (f &Fn) v_fn_module() string {
 	return f.mod
 }
 
-pub fn (f Fn) v_fn_name() string {
+pub fn (f &Fn) v_fn_name() string {
 	return f.name.replace('${f.mod}__', '')
 }
 
+pub fn (f &Fn) str_for_error() string {
+	// Build the args for the error
+                       mut s := ''
+                       for i, a in f.args {
+                               if i == 0 {
+                                       if f.is_method {
+                                               s += a.typ + '.' + f.name + '('
+                                               continue
+                                       }
+                                       s += f.name + '('
+                               }
+                               s += a.typ
+                               if i < f.args.len - 1 {
+                                       s += ', '
+                               }
+                       }
+       return s + ')'
+}
+
+
diff --git a/vlib/compiler/gen_c.v b/vlib/compiler/gen_c.v
index afc1c5cae9..98659a8100 100644
--- a/vlib/compiler/gen_c.v
+++ b/vlib/compiler/gen_c.v
@@ -145,18 +145,23 @@ fn (p mut Parser) gen_handle_option_or_else(_typ, name string, fn_call_ph int) s
 fn types_to_c(types []Type, table &Table) string {
 	mut sb := strings.new_builder(10)
 	for t in types {
-		if t.cat != .union_ && t.cat != .struct_ && t.cat != .objc_interface {
+		//if t.cat != .union_ && t.cat != .struct_ && t.cat != .objc_interface {
+		if !(t.cat in [.union_, .struct_, .objc_interface, .interface_]) {
 			continue
 		}
 		//if is_atomic {
 			//sb.write('_Atomic ')
 		//}
-		if t.cat ==  .objc_interface {
+		if t.cat == .objc_interface {
 			sb.writeln('@interface $t.name : $t.parent { @public')
 		}
 		else {
 			kind := if t.cat == .union_ {'union'} else {'struct'}
 			sb.writeln('$kind $t.name {')
+			if t.cat == .interface_ {
+				sb.writeln('\tvoid* _object;')
+				sb.writeln('\tint _interface_idx; // int t')
+			}
 		}
 		for field in t.fields {
 			sb.write('\t')
@@ -238,6 +243,11 @@ fn (table mut Table) fn_gen_name(f &Fn) string {
 			}
 		}
 	}
+	if f.is_interface {
+	//       iname := f.args[0].typ // Speaker
+		//         	var := p.expr_var.name
+		return ''
+	}
 	// Avoid name conflicts (with things like abs(), print() etc).
 	// Generate v_abs(), v_print()
 	// TODO duplicate functionality
diff --git a/vlib/compiler/main.v b/vlib/compiler/main.v
index 0b1f18812d..5038ecdbb0 100644
--- a/vlib/compiler/main.v
+++ b/vlib/compiler/main.v
@@ -297,6 +297,7 @@ pub fn (v mut V) compile() {
 		def.writeln('\nstring _STR(const char*, ...);\n')
 		def.writeln('\nstring _STR_TMP(const char*, ...);\n')
 		def.writeln(cgen.fns.join_lines()) // fn definitions
+		def.writeln(v.interface_table())
 	} $else {
 		def.writeln(v.type_definitions())
 	}
diff --git a/vlib/compiler/parser.v b/vlib/compiler/parser.v
index 97398625a7..272a367176 100644
--- a/vlib/compiler/parser.v
+++ b/vlib/compiler/parser.v
@@ -697,8 +697,8 @@ fn (p mut Parser) check_string() string {
 }
 
 fn (p mut Parser) check_not_reserved () {
-	if Reserved_Types[p.lit] { 
-		p.error('`$p.lit` can\'t be used as name') 
+	if Reserved_Types[p.lit] {
+		p.error('`$p.lit` can\'t be used as name')
 	}
 }
 
@@ -2053,6 +2053,7 @@ fn (p mut Parser) indot_expr() string {
 	return typ
 }
 
+// { user | name: 'new name' }
 fn (p mut Parser) assoc() string {
 	// println('assoc()')
 	p.next()
diff --git a/vlib/compiler/struct.v b/vlib/compiler/struct.v
index 0caec59e35..c6b584386a 100644
--- a/vlib/compiler/struct.v
+++ b/vlib/compiler/struct.v
@@ -222,12 +222,8 @@ fn (p mut Parser) struct_decl() {
 		p.fgenln('')
 	}
 	p.check(.rcbr)
-	if !is_c {
-		if !did_gen_something {
-			if p.first_pass() {
-				p.table.add_field(typ.name, '', 'EMPTY_STRUCT_DECLARATION', false, '', .private)
-			}
-		}
+	if !is_c && !did_gen_something && p.first_pass() {
+		p.table.add_field(typ.name, '', 'EMPTY_STRUCT_DECLARATION', false, '', .private)
 	}
 	p.fgenln('\n')
 }
diff --git a/vlib/compiler/table.v b/vlib/compiler/table.v
index 859c437c73..2e6867e898 100644
--- a/vlib/compiler/table.v
+++ b/vlib/compiler/table.v
@@ -538,16 +538,14 @@ fn (t &Type) find_method(name string) ?Fn {
 	return none
 }
 
-/*
-// TODO
-fn (t mutt Type) add_gen_type(type_name string) {
-	// println('add_gen_type($s)')
-	if t.gen_types.contains(type_name) {
+fn (table mut Table) add_gen_type(type_name, gen_type string) {
+	mut t := table.typesmap[type_name]
+	if gen_type in t.gen_types {
 		return
 	}
-	t.gen_types << type_name
+	t.gen_types << gen_type
+	table.typesmap[type_name] = t
 }
-*/
 
 fn (p &Parser) find_type(name string) Type {
 	typ := p.table.find_type(name)
@@ -576,7 +574,7 @@ fn (p mut Parser) check_types2(got_, expected_ string, throw bool) bool {
 	if p.pref.translated {
 		return true
 	}
-	if got == expected { 
+	if got == expected {
 		return true
 	}
 
@@ -728,7 +726,8 @@ fn (p mut Parser) satisfies_interface(interface_name, _typ string, throw bool) b
 	for method in int_typ.methods {
 		if !typ.has_method(method.name) {
 			// if throw {
-			p.error('Type "$_typ" doesn\'t satisfy interface "$interface_name" (method "$method.name" is not implemented)')
+			p.error('type `$_typ` doesn\'t satisfy interface ' +
+				'`$interface_name` (method `$method.name` is not implemented)')
 			// }
 			return false
 		}
diff --git a/vlib/compiler/tests/interface_test.v b/vlib/compiler/tests/interface_test.v
index 09df37643e..f37db18eeb 100644
--- a/vlib/compiler/tests/interface_test.v
+++ b/vlib/compiler/tests/interface_test.v
@@ -2,13 +2,16 @@ struct Dog {
 	breed string
 }
 
-fn (d Dog) speak() {
-	println('dog.speak()')
+struct Cat {
+       breed string
 }
 
-fn (d Dog) name() string {
-	return 'old gray'
-}
+
+fn (d Cat) name() string { return 'Cat' }
+fn (d Cat) speak() { println('meow') }
+
+fn (d Dog) speak() { println('woof') }
+fn (d Dog) name() string {  return 'Dog'}
 
 interface Speaker {
 	name() string
@@ -16,10 +19,14 @@ interface Speaker {
 }
 
 interface Speak2er {
-	speak()
 	name() string
+	speak()
 }
 
+struct Foo {
+	speaker Speaker
+}	
+
 fn perform_speak(s Speaker) bool {
 	s.speak()
 	return true
@@ -28,5 +35,11 @@ fn perform_speak(s Speaker) bool {
 fn test_perform_speak() {
 	d := Dog{}
 	assert perform_speak(d)
+	cat := Cat{}
+	assert perform_speak(cat)
+	f := Foo {
+		//speaker: d
+	}	
+
 }