Fix evaluation order of type conversions

hajimehoshi · neelance · commit dc374d327045 · 2017-06-09T02:26:10.000+02:00
diff --git a/compiler/expressions.go b/compiler/expressions.go
@@ -539,7 +539,7 @@ func (c *funcContext) translateExpr(expr ast.Expr) *expression {
 		plainFun := astutil.RemoveParens(e.Fun)
 
 		if astutil.IsTypeExpr(plainFun, c.p.Info.Info) {
-			return c.formatExpr("%s", c.translateConversion(e.Args[0], c.p.TypeOf(plainFun)))
+			return c.formatExpr("(%s)", c.translateConversion(e.Args[0], c.p.TypeOf(plainFun)))
 		}
 
 		sig := c.p.TypeOf(plainFun).Underlying().(*types.Signature)
diff --git a/tests/misc_test.go b/tests/misc_test.go
@@ -612,3 +612,14 @@ func TestReceiverCapture(t *testing.T) {
 		t.Fail()
 	}
 }
+
+func TestTypeConversion(t *testing.T) {
+	i1, i2, i3 := 4, 2, 2
+	if (i1-i2)/i3 != int(i1-i2)/int(i3) {
+		t.Fail()
+	}
+	f1, f2, f3 := 4.0, 2.0, 2.0
+	if (f1-f2)/f3 != float64(f1-f2)/float64(f3) {
+		t.Fail()
+	}
+}

Original file line number	Diff line number	Diff line change
`@@ -539,7 +539,7 @@ func (c funcContext) translateExpr(expr ast.Expr) expression {`
`539`	`539`	`plainFun := astutil.RemoveParens(e.Fun)`
`540`	`540`
`541`	`541`	`if astutil.IsTypeExpr(plainFun, c.p.Info.Info) {`
`542`		`- return c.formatExpr("%s", c.translateConversion(e.Args[0], c.p.TypeOf(plainFun)))`
	`542`	`+ return c.formatExpr("(%s)", c.translateConversion(e.Args[0], c.p.TypeOf(plainFun)))`
`543`	`543`	`}`
`544`	`544`
`545`	`545`	`sig := c.p.TypeOf(plainFun).Underlying().(*types.Signature)`