cmd/compile/internal/types2: print assignment operation for invalid operation errors

When invoking check.binary for assignment operation, the expression will
be nil, thus for printing the assignment operation error message, we
need to reconstruct the statement from lhs, op, rhs.

Fixes #48472

Change-Id: Ie38c3dd8069b47e508968d6e43cedcf7536559ef
Reviewed-on: https://go-review.googlesource.com/c/go/+/357229
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

diff --git a/src/cmd/compile/internal/types2/expr.go b/src/cmd/compile/internal/types2/expr.go
index 2d22c027eb8767eb8207653ab3004770fb1cf7dd..1001554739614cc01d6c301c8408baa6efd420bd 100644 (file)
--- a/src/cmd/compile/internal/types2/expr.go
+++ b/src/cmd/compile/internal/types2/expr.go
@@ -1025,7 +1025,11 @@ func (check *Checker) binary(x *operand, e syntax.Expr, lhs, rhs syntax.Expr, op
                // only report an error if we have valid types
                // (otherwise we had an error reported elsewhere already)
                if x.typ != Typ[Invalid] && y.typ != Typ[Invalid] {
-                       check.errorf(x, invalidOp+"%s (mismatched types %s and %s)", e, x.typ, y.typ)
+                       if e != nil {
+                               check.errorf(x, invalidOp+"%s (mismatched types %s and %s)", e, x.typ, y.typ)
+                       } else {
+                               check.errorf(x, invalidOp+"%s %s= %s (mismatched types %s and %s)", lhs, op, rhs, x.typ, y.typ)
+                       }
                }
                x.mode = invalid
                return

diff --git a/src/cmd/compile/internal/types2/testdata/fixedbugs/issue48472.go2 b/src/cmd/compile/internal/types2/testdata/fixedbugs/issue48472.go2
index 5fefcaf22bcfa881ada7008a74bdc744c59564da..2d908f4c8b56c7c6ab799080a5c863bfd5a234d5 100644 (file)
--- a/src/cmd/compile/internal/types2/testdata/fixedbugs/issue48472.go2
+++ b/src/cmd/compile/internal/types2/testdata/fixedbugs/issue48472.go2
@@ -9,3 +9,8 @@ func g() {
        var i int
        _ = s /* ERROR invalid operation: s \+ i \(mismatched types string and int\) */ + i
 }
+
+func f(i int) int {
+        i /* ERROR invalid operation: i \+= "1" \(mismatched types int and untyped string\) */ += "1"
+        return i
+}