From 43f0ddd25d26b0c5ffc1eafe620f773582fffed0 Mon Sep 17 00:00:00 2001
From: James Shubin <james@shubin.ca>
Date: Sun, 20 Jan 2019 03:39:30 -0500
Subject: [PATCH] lang: unification: Catch unification error on typed if expr

I found a case where we had two missing unification rules. Now fixed in
the previous commits, and including this test to show I'm responsible.
I've added the same test in two locations for redundancy and as an
example.
---
 lang/interpret_test/TestAstFunc1/fail2.graph  |  1 +
 .../TestAstFunc1/fail2/main.mcl               |  9 +++
 lang/unification_test.go                      | 55 +++++++++++++++++++
 3 files changed, 65 insertions(+)
 create mode 100644 lang/interpret_test/TestAstFunc1/fail2.graph
 create mode 100644 lang/interpret_test/TestAstFunc1/fail2/main.mcl

diff --git a/lang/interpret_test/TestAstFunc1/fail2.graph b/lang/interpret_test/TestAstFunc1/fail2.graph
new file mode 100644
index 00000000..456bf1cb
--- /dev/null
+++ b/lang/interpret_test/TestAstFunc1/fail2.graph
@@ -0,0 +1 @@
+# err: can't unify, invariant illogicality with equality: base kind does not match (2 != 3)
diff --git a/lang/interpret_test/TestAstFunc1/fail2/main.mcl b/lang/interpret_test/TestAstFunc1/fail2/main.mcl
new file mode 100644
index 00000000..0ca8a2de
--- /dev/null
+++ b/lang/interpret_test/TestAstFunc1/fail2/main.mcl
@@ -0,0 +1,9 @@
+import "fmt"
+$x str = if true {	# should fail unification
+	42
+} else {
+	13
+}
+test "t1" {
+	anotherstr => fmt.printf("hello %s", $x),
+}
diff --git a/lang/unification_test.go b/lang/unification_test.go
index 664e1608..6cb55cd4 100644
--- a/lang/unification_test.go
+++ b/lang/unification_test.go
@@ -645,6 +645,61 @@ func TestUnification1(t *testing.T) {
 			},
 		})
 	}
+	{
+		//import "fmt"
+		//$x str = if true {	# should fail unification
+		//	42
+		//} else {
+		//	13
+		//}
+		//test "t1" {
+		//	stringptr => fmt.printf("hello %s", $x),
+		//}
+		cond := &ExprIf{
+			Condition:  &ExprBool{V: true},
+			ThenBranch: &ExprInt{V: 42},
+			ElseBranch: &ExprInt{V: 13},
+		}
+		cond.SetType(types.TypeStr) // should fail unification
+		expr := &ExprCall{
+			Name: "fmt.printf",
+			Args: []interfaces.Expr{
+				&ExprStr{
+					V: "hello %s",
+				},
+				&ExprVar{
+					Name: "x", // the var
+				},
+			},
+		}
+		stmt := &StmtProg{
+			Prog: []interfaces.Stmt{
+				&StmtImport{
+					Name: "fmt",
+				},
+				&StmtBind{
+					Ident: "x", // the var
+					Value: cond,
+				},
+				&StmtRes{
+					Kind: "test",
+					Name: &ExprStr{V: "t1"},
+					Contents: []StmtResContents{
+						&StmtResField{
+							Field: "anotherstr",
+							Value: expr,
+						},
+					},
+				},
+			},
+		}
+		testCases = append(testCases, test{
+			name:      "typed if expr",
+			ast:       stmt,
+			fail:      true,
+			experrstr: "can't unify, invariant illogicality with equality: base kind does not match (2 != 3)",
+		})
+	}
 
 	names := []string{}
 	for index, tc := range testCases { // run all the tests