cmd/compile: enable reverse type inference

For #59338.

Change-Id: I8141d421cdc60e47ee5794fc1ca81246bd8a8a25
Reviewed-on: https://go-review.googlesource.com/c/go/+/491475
Reviewed-by: Robert Findley <rfindley@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
Run-TryBot: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

diff --git a/src/cmd/compile/internal/noder/irgen.go b/src/cmd/compile/internal/noder/irgen.go
index 3adf9e5d11d82bd4278d8c5d8ea4a2eb2e99dbd1..8f31687e9ff6a55b03c17935862c660e73aa243e 100644 (file)
--- a/src/cmd/compile/internal/noder/irgen.go
+++ b/src/cmd/compile/internal/noder/irgen.go
@@ -50,8 +50,9 @@ func checkFiles(m posMap, noders []*noder) (*types2.Package, *types2.Info) {
                        }
                        base.ErrorfAt(m.makeXPos(terr.Pos), terr.Code, "%s", msg)
                },
-               Importer: &importer,
-               Sizes:    &gcSizes{},
+               Importer:                   &importer,
+               Sizes:                      &gcSizes{},
+               EnableReverseTypeInference: true,
        }
        info := &types2.Info{
                StoreTypesInSyntax: true,

diff --git a/src/cmd/compile/internal/types2/stdlib_test.go b/src/cmd/compile/internal/types2/stdlib_test.go
index c5903a12d381425969076acf4ca9f4289eaebddf..d9db545dc669e4de7e9efe185949a9d4fef2c864 100644 (file)
--- a/src/cmd/compile/internal/types2/stdlib_test.go
+++ b/src/cmd/compile/internal/types2/stdlib_test.go
@@ -138,7 +138,11 @@ func testTestDir(t *testing.T, path string, ignore ...string) {
                }
                file, err := syntax.ParseFile(filename, nil, nil, 0)
                if err == nil {
-                       conf := Config{GoVersion: goVersion, Importer: stdLibImporter}
+                       conf := Config{
+                               GoVersion:                  goVersion,
+                               Importer:                   stdLibImporter,
+                               EnableReverseTypeInference: true,
+                       }
                        _, err = conf.Check(filename, []*syntax.File{file}, nil)
                }
 
@@ -250,8 +254,9 @@ func typecheckFiles(t *testing.T, path string, filenames []string) {
 
        // typecheck package files
        conf := Config{
-               Error:    func(err error) { t.Error(err) },
-               Importer: stdLibImporter,
+               Error:                      func(err error) { t.Error(err) },
+               Importer:                   stdLibImporter,
+               EnableReverseTypeInference: true,
        }
        info := Info{Uses: make(map[*syntax.Name]Object)}
        conf.Check(path, files, &info)

diff --git a/src/go/types/stdlib_test.go b/src/go/types/stdlib_test.go
index f2290c572599f906700ac0d021cc622636fbc0ad..88338cc2bdacbc216134206915a1139f3affc66a 100644 (file)
--- a/src/go/types/stdlib_test.go
+++ b/src/go/types/stdlib_test.go
@@ -139,7 +139,11 @@ func testTestDir(t *testing.T, path string, ignore ...string) {
                // parse and type-check file
                file, err := parser.ParseFile(fset, filename, nil, 0)
                if err == nil {
-                       conf := Config{GoVersion: goVersion, Importer: stdLibImporter}
+                       conf := Config{
+                               GoVersion: goVersion,
+                               Importer:  stdLibImporter,
+                       }
+                       *boolFieldAddr(&conf, "_EnableReverseTypeInference") = true
                        _, err = conf.Check(filename, fset, []*ast.File{file}, nil)
                }
 
@@ -267,6 +271,7 @@ func typecheckFiles(t *testing.T, path string, filenames []string) {
                },
                Importer: stdLibImporter,
        }
+       *boolFieldAddr(&conf, "_EnableReverseTypeInference") = true
        info := Info{Uses: make(map[*ast.Ident]Object)}
        conf.Check(path, fset, files, &info)
 

diff --git a/test/fixedbugs/issue59338.go b/test/fixedbugs/issue59338.go
new file mode 100644 (file)
index 0000000..dc8604f
--- /dev/null
+++ b/test/fixedbugs/issue59338.go
@@ -0,0 +1,39 @@
+// run
+
+// Copyright 2023 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.
+
+// Smoke test for reverse type inference.
+// The type checker has more expansive tests.
+
+package main
+
+func main() {
+       var f1 func(int) int
+       f1 = g1
+       if f1(1) != g1(1) {
+               panic(1)
+       }
+
+       var f2 func(int) string = g2
+       if f2(2) != "" {
+               panic(2)
+       }
+
+       // Disabled for now - requires some noder work
+       // TODO fix this
+       // if g3(g1, 3) != g1(3) {
+       //      panic(3)
+       // }
+
+       // if g4(g2, 4) != "" {
+       //      panic(4)
+       // }
+}
+
+func g1[P any](x P) P    { return x }
+func g2[P, Q any](x P) Q { var q Q; return q }
+
+func g3(f1 func(int) int, x int) int       { return f1(x) }
+func g4(f2 func(int) string, x int) string { return f2(x) }