go/types, types2: fine-tune inference tracing output (debugging support)

No changes to non-tracing related code.

Change-Id: I3d004528281111a4479a02543a3e5443485182cf
Reviewed-on: https://go-review.googlesource.com/c/go/+/474135
Reviewed-by: Robert Griesemer <gri@google.com>
Run-TryBot: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>

diff --git a/src/cmd/compile/internal/types2/infer.go b/src/cmd/compile/internal/types2/infer.go
index cba7ecf86ae40c6feb1a997f8af1d92f5ba5ea62..ed11ae8e4c7c0dabde099fadc0dc1a9f085f4489 100644 (file)
--- a/src/cmd/compile/internal/types2/infer.go
+++ b/src/cmd/compile/internal/types2/infer.go
@@ -30,7 +30,7 @@ func (check *Checker) infer(pos syntax.Pos, tparams []*TypeParam, targs []Type,
        }
 
        if traceInference {
-               check.dump("-- infer %s%s ➞ %s", tparams, params, targs)
+               check.dump("== infer : %s%s ➞ %s", tparams, params, targs) // aligned with rename print below
                defer func() {
                        check.dump("=> %s ➞ %s\n", tparams, inferred)
                }()
@@ -53,7 +53,7 @@ func (check *Checker) infer(pos syntax.Pos, tparams []*TypeParam, targs []Type,
        tparams, params = check.renameTParams(pos, tparams, params)
 
        if traceInference {
-               check.dump("after rename: %s%s ➞ %s\n", tparams, params, targs)
+               check.dump("-- rename: %s%s ➞ %s\n", tparams, params, targs)
        }
 
        // Make sure we have a "full" list of type arguments, some of which may
@@ -142,8 +142,8 @@ func (check *Checker) infer(pos syntax.Pos, tparams []*TypeParam, targs []Type,
        // use information from function arguments
 
        if traceInference {
-               u.tracef("parameters: %s", params)
-               u.tracef("arguments : %s", args)
+               u.tracef("== function parameters: %s", params)
+               u.tracef("-- function arguments : %s", args)
        }
 
        for i, arg := range args {
@@ -183,7 +183,7 @@ func (check *Checker) infer(pos syntax.Pos, tparams []*TypeParam, targs []Type,
        // use information from type parameter constraints
 
        if traceInference {
-               u.tracef("type parameters: %s", tparams)
+               u.tracef("== type parameters: %s", tparams)
        }
 
        // Unify type parameters with their constraints as long
@@ -201,21 +201,25 @@ func (check *Checker) infer(pos syntax.Pos, tparams []*TypeParam, targs []Type,
        // here could handle the respective type parameters only,
        // but that will come at a cost of extra complexity which
        // may not be worth it.)
-       for {
+       for i := 0; ; i++ {
                nn := u.unknowns()
+               if traceInference {
+                       if i > 0 {
+                               fmt.Println()
+                       }
+                       u.tracef("-- iteration %d", i)
+               }
 
                for _, tpar := range tparams {
                        tx := u.at(tpar)
-                       if traceInference && tx != nil {
-                               u.tracef("%s = %s", tpar, tx)
+                       core, single := coreTerm(tpar)
+                       if traceInference {
+                               u.tracef("-- type parameter %s = %s: core(%s) = %s, single = %v", tpar, tx, tpar, core, single)
                        }
 
                        // If there is a core term (i.e., a core type with tilde information)
                        // unify the type parameter with the core type.
-                       if core, single := coreTerm(tpar); core != nil {
-                               if traceInference {
-                                       u.tracef("core(%s) = %s (single = %v)", tpar, core, single)
-                               }
+                       if core != nil {
                                // A type parameter can be unified with its core type in two cases.
                                switch {
                                case tx != nil:
@@ -240,9 +244,6 @@ func (check *Checker) infer(pos syntax.Pos, tparams []*TypeParam, targs []Type,
                                        u.set(tpar, core.typ)
                                }
                        } else {
-                               if traceInference {
-                                       u.tracef("core(%s) = nil", tpar)
-                               }
                                if tx != nil {
                                        // We don't have a core type, but the type argument tx is known.
                                        // It must have (at least) all the methods of the type constraint,
@@ -272,7 +273,7 @@ func (check *Checker) infer(pos syntax.Pos, tparams []*TypeParam, targs []Type,
        // use information from untyped contants
 
        if traceInference {
-               u.tracef("untyped: %v", untyped)
+               u.tracef("== untyped arguments: %v", untyped)
        }
 
        // Some generic parameters with untyped arguments may have been given a type by now.

diff --git a/src/go/types/infer.go b/src/go/types/infer.go
index 8c42bdc15cd2076d2bbd4cfc6c76c117356a117f..c2138f4a36bc728218714a19250b9a801e012b02 100644 (file)
--- a/src/go/types/infer.go
+++ b/src/go/types/infer.go
@@ -32,7 +32,7 @@ func (check *Checker) infer(posn positioner, tparams []*TypeParam, targs []Type,
        }
 
        if traceInference {
-               check.dump("-- infer %s%s ➞ %s", tparams, params, targs)
+               check.dump("== infer : %s%s ➞ %s", tparams, params, targs) // aligned with rename print below
                defer func() {
                        check.dump("=> %s ➞ %s\n", tparams, inferred)
                }()
@@ -55,7 +55,7 @@ func (check *Checker) infer(posn positioner, tparams []*TypeParam, targs []Type,
        tparams, params = check.renameTParams(posn.Pos(), tparams, params)
 
        if traceInference {
-               check.dump("after rename: %s%s ➞ %s\n", tparams, params, targs)
+               check.dump("-- rename: %s%s ➞ %s\n", tparams, params, targs)
        }
 
        // Make sure we have a "full" list of type arguments, some of which may
@@ -144,8 +144,8 @@ func (check *Checker) infer(posn positioner, tparams []*TypeParam, targs []Type,
        // use information from function arguments
 
        if traceInference {
-               u.tracef("parameters: %s", params)
-               u.tracef("arguments : %s", args)
+               u.tracef("== function parameters: %s", params)
+               u.tracef("-- function arguments : %s", args)
        }
 
        for i, arg := range args {
@@ -185,7 +185,7 @@ func (check *Checker) infer(posn positioner, tparams []*TypeParam, targs []Type,
        // use information from type parameter constraints
 
        if traceInference {
-               u.tracef("type parameters: %s", tparams)
+               u.tracef("== type parameters: %s", tparams)
        }
 
        // Unify type parameters with their constraints as long
@@ -203,21 +203,25 @@ func (check *Checker) infer(posn positioner, tparams []*TypeParam, targs []Type,
        // here could handle the respective type parameters only,
        // but that will come at a cost of extra complexity which
        // may not be worth it.)
-       for {
+       for i := 0; ; i++ {
                nn := u.unknowns()
+               if traceInference {
+                       if i > 0 {
+                               fmt.Println()
+                       }
+                       u.tracef("-- iteration %d", i)
+               }
 
                for _, tpar := range tparams {
                        tx := u.at(tpar)
-                       if traceInference && tx != nil {
-                               u.tracef("%s = %s", tpar, tx)
+                       core, single := coreTerm(tpar)
+                       if traceInference {
+                               u.tracef("-- type parameter %s = %s: core(%s) = %s, single = %v", tpar, tx, tpar, core, single)
                        }
 
                        // If there is a core term (i.e., a core type with tilde information)
                        // unify the type parameter with the core type.
-                       if core, single := coreTerm(tpar); core != nil {
-                               if traceInference {
-                                       u.tracef("core(%s) = %s (single = %v)", tpar, core, single)
-                               }
+                       if core != nil {
                                // A type parameter can be unified with its core type in two cases.
                                switch {
                                case tx != nil:
@@ -242,9 +246,6 @@ func (check *Checker) infer(posn positioner, tparams []*TypeParam, targs []Type,
                                        u.set(tpar, core.typ)
                                }
                        } else {
-                               if traceInference {
-                                       u.tracef("core(%s) = nil", tpar)
-                               }
                                if tx != nil {
                                        // We don't have a core type, but the type argument tx is known.
                                        // It must have (at least) all the methods of the type constraint,
@@ -274,7 +275,7 @@ func (check *Checker) infer(posn positioner, tparams []*TypeParam, targs []Type,
        // use information from untyped contants
 
        if traceInference {
-               u.tracef("untyped: %v", untyped)
+               u.tracef("== untyped arguments: %v", untyped)
        }
 
        // Some generic parameters with untyped arguments may have been given a type by now.