From: Robert Griesemer <gri@golang.org>
Date: Thu, 19 Nov 2020 17:09:15 +0000 (-0800)
Subject: [dev.typeparams] cmd/compile/internal/types2: report an error for invalid constant... 
X-Git-Tag: go1.17beta1~1473^2~194
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=0123c9b321;p=gostls13.git

[dev.typeparams] cmd/compile/internal/types2: report an error for invalid constant values

This is https://golang.org/cl/271377 ported to types2.

Updates #42695.

Change-Id: I475bdcaeace5b0e87d4476a6d660996534289666
Reviewed-on: https://go-review.googlesource.com/c/go/+/271520
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
---

diff --git a/src/cmd/compile/internal/types2/expr.go b/src/cmd/compile/internal/types2/expr.go
index 7c07950b01..94649ca4cc 100644
--- a/src/cmd/compile/internal/types2/expr.go
+++ b/src/cmd/compile/internal/types2/expr.go
@@ -1168,7 +1168,11 @@ func (check *Checker) exprInternal(x *operand, e syntax.Expr, hint Type) exprKin
 	case *syntax.BasicLit:
 		x.setConst(e.Kind, e.Value)
 		if x.mode == invalid {
-			check.invalidASTf(e, "invalid literal %v", e.Value)
+			// The parser already establishes syntactic correctness.
+			// If we reach here it's because of number under-/overflow.
+			// TODO(gri) setConst (and in turn the go/constant package)
+			// should return an error describing the issue.
+			check.errorf(e, "malformed constant: %s", e.Value)
 			goto Error
 		}
 
diff --git a/src/cmd/compile/internal/types2/fixedbugs/issue42695.src b/src/cmd/compile/internal/types2/fixedbugs/issue42695.src
new file mode 100644
index 0000000000..d0d6200969
--- /dev/null
+++ b/src/cmd/compile/internal/types2/fixedbugs/issue42695.src
@@ -0,0 +1,17 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package issue42695
+
+const _ = 6e5518446744 // ERROR malformed constant
+const _ uint8 = 6e5518446744 // ERROR malformed constant
+
+var _ = 6e5518446744 // ERROR malformed constant
+var _ uint8 = 6e5518446744 // ERROR malformed constant
+
+func f(x int) int {
+        return x + 6e5518446744 // ERROR malformed constant
+}
+
+var _ = f(6e5518446744 /* ERROR malformed constant */ )
diff --git a/src/cmd/compile/internal/types2/operand.go b/src/cmd/compile/internal/types2/operand.go
index fe88921893..0a19760423 100644
--- a/src/cmd/compile/internal/types2/operand.go
+++ b/src/cmd/compile/internal/types2/operand.go
@@ -211,9 +211,15 @@ func (x *operand) setConst(k syntax.LitKind, lit string) {
 		unreachable()
 	}
 
+	val := constant.MakeFromLiteral(lit, tok, 0)
+	if val.Kind() == constant.Unknown {
+		x.mode = invalid
+		x.typ = Typ[Invalid]
+		return
+	}
 	x.mode = constant_
 	x.typ = Typ[kind]
-	x.val = constant.MakeFromLiteral(lit, tok, 0)
+	x.val = val
 }
 
 // isNil reports whether x is the nil value.