compiler: fix panic for inline invocations

Close #3993.

Signed-off-by: Tural Devrishev <tural@nspcc.ru>

Author: Tural Devrishev

pkg/compiler/codegen.go

@@ -316,6 +316,10 @@ func (c *codegen) emitStoreVar(pkg string, name string) {
 		return
 	}
 	vi := c.getVarIndex(pkg, name)
+	if vi.index == unspecifiedVarIndex && vi.ctx != nil {
+		c.scope.newLocal(name)
+		vi = c.getVarIndex(pkg, name)
+	}
 	c.emitStoreByIndex(vi.refType, vi.index)
 }
 

pkg/compiler/inline_test.go

@@ -454,3 +454,47 @@ func TestInlineForeignType(t *testing.T) {
 		}`
 	eval(t, src, big.NewInt(29))
 }
+
+func TestInlineModifyArg(t *testing.T) {
+	src := `package foo
+		import "github.com/nspcc-dev/neo-go/pkg/compiler/testdata/inline/d"
+
+		func Main() int {
+			return d.Negate(-42)
+		}`
+	eval(t, src, big.NewInt(42))
+}
+
+func TestInlineMixedArgs(t *testing.T) {
+	src := `package foo
+		import "github.com/nspcc-dev/neo-go/pkg/compiler/testdata/inline/d"
+
+		func someCall() int { return 7 }
+
+		func Main() int {
+			return d.AddNeg(-3, someCall())
+		}`
+	eval(t, src, big.NewInt(-4))
+}
+
+func TestInlineChain(t *testing.T) {
+	src := `package foo
+		import "github.com/nspcc-dev/neo-go/pkg/compiler/testdata/inline/d"
+
+		func Main() int {
+			return d.Wrap2(-2)
+		}`
+	eval(t, src, big.NewInt(2))
+}
+
+func TestInlineSlice(t *testing.T) {
+	src := `package foo
+		import "github.com/nspcc-dev/neo-go/pkg/compiler/testdata/inline/d"
+
+		func Main() int {
+			s := make([]int, 1)
+			d.SetOneFirstElem(s)
+			return s[0]
+		}`
+	eval(t, src, big.NewInt(1))
+}

pkg/compiler/testdata/inline/d/d.go

@@ -0,0 +1,28 @@
+package d
+
+func Negate(n int) int {
+	n *= -1
+	return n
+}
+
+func AddNeg(a int, b int) int {
+	a *= -1
+	b *= -1
+	return a + b
+}
+
+func Wrap1(n int) int {
+	n *= -1
+	n *= -1
+	return Negate(n)
+}
+
+func Wrap2(n int) int {
+	n *= -1
+	n *= -1
+	return Wrap1(n)
+}
+
+func SetOneFirstElem(s []int) {
+	s[0] = 1
+}