diff --git a/compiler/compiler.go b/compiler/compiler.go
index 98ae5a9a..74fb8e6a 100644
--- a/compiler/compiler.go
+++ b/compiler/compiler.go
@@ -2400,7 +2400,7 @@ func (c *Compiler) parseBinOp(op token.Token, typ types.Type, x, y llvm.Value, p
 					return c.builder.CreateICmp(llvm.IntUGE, x, y, ""), nil
 				}
 			default:
-				return llvm.Value{}, c.makeError(pos, "todo: binop on integer: "+op.String())
+				panic("binop on integer: " + op.String())
 			}
 		} else if typ.Info()&types.IsFloat != 0 {
 			// Operations on floats
@@ -2413,8 +2413,6 @@ func (c *Compiler) parseBinOp(op token.Token, typ types.Type, x, y llvm.Value, p
 				return c.builder.CreateFMul(x, y, ""), nil
 			case token.QUO: // /
 				return c.builder.CreateFDiv(x, y, ""), nil
-			case token.REM: // %
-				return c.builder.CreateFRem(x, y, ""), nil
 			case token.EQL: // ==
 				return c.builder.CreateFCmp(llvm.FloatOEQ, x, y, ""), nil
 			case token.NEQ: // !=
@@ -2428,7 +2426,27 @@ func (c *Compiler) parseBinOp(op token.Token, typ types.Type, x, y llvm.Value, p
 			case token.GEQ: // >=
 				return c.builder.CreateFCmp(llvm.FloatOGE, x, y, ""), nil
 			default:
-				return llvm.Value{}, c.makeError(pos, "todo: binop on float: "+op.String())
+				panic("binop on float: " + op.String())
+			}
+		} else if typ.Info()&types.IsComplex != 0 {
+			indexr := llvm.ConstInt(c.ctx.Int32Type(), 0, false)
+			indexi := llvm.ConstInt(c.ctx.Int32Type(), 1, false)
+			r1 := c.builder.CreateExtractElement(x, indexr, "r1")
+			r2 := c.builder.CreateExtractElement(y, indexr, "r2")
+			i1 := c.builder.CreateExtractElement(x, indexi, "i1")
+			i2 := c.builder.CreateExtractElement(y, indexi, "i2")
+			switch op {
+			case token.EQL: // ==
+				req := c.builder.CreateFCmp(llvm.FloatOEQ, r1, r2, "")
+				ieq := c.builder.CreateFCmp(llvm.FloatOEQ, i1, i2, "")
+				return c.builder.CreateAnd(req, ieq, ""), nil
+			case token.NEQ: // !=
+				req := c.builder.CreateFCmp(llvm.FloatOEQ, r1, r2, "")
+				ieq := c.builder.CreateFCmp(llvm.FloatOEQ, i1, i2, "")
+				neq := c.builder.CreateAnd(req, ieq, "")
+				return c.builder.CreateNot(neq, ""), nil
+			default:
+				return llvm.Value{}, c.makeError(pos, "todo: binop on complex number: "+op.String())
 			}
 		} else if typ.Info()&types.IsBoolean != 0 {
 			// Operations on booleans
@@ -2438,7 +2456,7 @@ func (c *Compiler) parseBinOp(op token.Token, typ types.Type, x, y llvm.Value, p
 			case token.NEQ: // !=
 				return c.builder.CreateICmp(llvm.IntNE, x, y, ""), nil
 			default:
-				return llvm.Value{}, c.makeError(pos, "todo: binop on boolean: "+op.String())
+				panic("binop on bool: " + op.String())
 			}
 		} else if typ.Kind() == types.UnsafePointer {
 			// Operations on pointers
@@ -2448,7 +2466,7 @@ func (c *Compiler) parseBinOp(op token.Token, typ types.Type, x, y llvm.Value, p
 			case token.NEQ: // !=
 				return c.builder.CreateICmp(llvm.IntNE, x, y, ""), nil
 			default:
-				return llvm.Value{}, c.makeError(pos, "todo: binop on pointer: "+op.String())
+				panic("binop on pointer: " + op.String())
 			}
 		} else if typ.Info()&types.IsString != 0 {
 			// Operations on strings
@@ -2471,7 +2489,7 @@ func (c *Compiler) parseBinOp(op token.Token, typ types.Type, x, y llvm.Value, p
 			case token.GEQ: // >=
 				return c.createRuntimeCall("stringLess", []llvm.Value{y, x}, ""), nil
 			default:
-				return llvm.Value{}, c.makeError(pos, "todo: binop on string: "+op.String())
+				panic("binop on string: " + op.String())
 			}
 		} else {
 			return llvm.Value{}, c.makeError(pos, "todo: unknown basic type in binop: "+typ.String())
diff --git a/testdata/binop.go b/testdata/binop.go
index e98545f9..f58a94c1 100644
--- a/testdata/binop.go
+++ b/testdata/binop.go
@@ -47,6 +47,20 @@ func main() {
 	println(s2 == Struct2{"foo", 0.0, 7})
 	println(s2 == Struct2{"foo", 1.0, 5})
 	println(s2 == Struct2{"foo", 1.0, 7})
+
+	println("complex numbers")
+	println(c64 == 3+2i)
+	println(c64 == 4+2i)
+	println(c64 == 3+3i)
+	println(c64 != 3+2i)
+	println(c64 != 4+2i)
+	println(c64 != 3+3i)
+	println(c128 == 3+2i)
+	println(c128 == 4+2i)
+	println(c128 == 3+3i)
+	println(c128 != 3+2i)
+	println(c128 != 4+2i)
+	println(c128 != 3+3i)
 }
 
 var x = true
@@ -58,6 +72,9 @@ var s2 = Struct2{"foo", 0.0, 5}
 
 var a1 = [2]int{1, 2}
 
+var c64 = 3 + 2i
+var c128 = 4 + 3i
+
 type Int int
 
 type Struct1 struct {
diff --git a/testdata/binop.txt b/testdata/binop.txt
index 72e67198..8d1f37be 100644
--- a/testdata/binop.txt
+++ b/testdata/binop.txt
@@ -41,3 +41,16 @@ true
 false
 true
 false
+complex numbers
+true
+false
+false
+false
+true
+true
+false
+false
+false
+true
+true
+true