From e229d0c1c317f4bcdb74871a39731734d629b649 Mon Sep 17 00:00:00 2001
From: Nick Treleaven <n@trelsoft.com>
Date: Fri, 12 Mar 2021 12:18:52 +0000
Subject: [PATCH] checker: improve error message for invalid property (#9263)

---
 vlib/v/checker/checker.v                  |  2 +-
 vlib/v/checker/tests/invalid_property.out | 18 ++++++++++++++++++
 vlib/v/checker/tests/invalid_property.vv  |  6 ++++++
 3 files changed, 25 insertions(+), 1 deletion(-)
 create mode 100644 vlib/v/checker/tests/invalid_property.out
 create mode 100644 vlib/v/checker/tests/invalid_property.vv

diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 7bf98ce7c9..4c98854b0f 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -2335,7 +2335,7 @@ pub fn (mut c Checker) selector_expr(mut selector_expr ast.SelectorExpr) table.T
 	}
 	if sym.kind !in [.struct_, .aggregate, .interface_, .sum_type] {
 		if sym.kind != .placeholder {
-			c.error('`$sym.name` is not a struct', selector_expr.pos)
+			c.error('`$sym.name` has no property `$selector_expr.field_name`', selector_expr.pos)
 		}
 	} else {
 		if sym.info is table.Struct {
diff --git a/vlib/v/checker/tests/invalid_property.out b/vlib/v/checker/tests/invalid_property.out
new file mode 100644
index 0000000000..e7839a42b9
--- /dev/null
+++ b/vlib/v/checker/tests/invalid_property.out
@@ -0,0 +1,18 @@
+vlib/v/checker/tests/invalid_property.vv:2:7: error: `string` has no property `length`
+    1 | s :=''
+    2 | _ = s.length
+      |       ~~~~~~
+    3 | _ = [1,2].foo
+    4 |
+vlib/v/checker/tests/invalid_property.vv:3:11: error: `[]int` has no property `foo`
+    1 | s :=''
+    2 | _ = s.length
+    3 | _ = [1,2].foo
+      |           ~~~
+    4 | 
+    5 | mut fa := [3,4]!
+vlib/v/checker/tests/invalid_property.vv:6:8: error: `[2]int` has no property `bar`
+    4 | 
+    5 | mut fa := [3,4]!
+    6 | _ = fa.bar
+      |        ~~~
diff --git a/vlib/v/checker/tests/invalid_property.vv b/vlib/v/checker/tests/invalid_property.vv
new file mode 100644
index 0000000000..427c2e7fb7
--- /dev/null
+++ b/vlib/v/checker/tests/invalid_property.vv
@@ -0,0 +1,6 @@
+s :=''
+_ = s.length
+_ = [1,2].foo
+
+mut fa := [3,4]!
+_ = fa.bar