cmd/compile: fix various small bugs related to type lists

Fix various small bugs related to delaying transformations due to type
params. Most of these relate to the need to delay a transformation when
an argument of an expression or statement has a type parameter that has
a structural constraint. The structural constraint implies the operation
should work, but the transformation can't happen until the actual value
of the type parameter is known.

 - delay transformations for send statements and return statements if
   any args/values have type params.

 - similarly, delay transformation of a call where the function arg has
   type parameters. This is mainly important for the case where the
   function arg is a pure type parameter, but has a structural
   constraint that requires it to be a function. Move the setting of
   n.Use to transformCall(), since we may not know how many return
   values there are until then, if the function arg is a type parameter.

 - set the type of unary expressions from the type2 type (as we do with
   most other expressions), since that works better with expressions
   with type params.

 - deal with these delayed transformations in subster.node() and convert
   the CALL checks to a switch statement.

 - make sure ir.CurFunc is set properly during stenciling, including
   closures (needed for transforming return statements during
   stenciling).

New test file typelist.go with tests for these cases.

Change-Id: I1b82f949d8cec47d906429209e846f4ebc8ec85e
Reviewed-on: https://go-review.googlesource.com/c/go/+/305729
Trust: Dan Scales <danscales@google.com>
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
This commit is contained in:
Dan Scales 2021-03-29 08:28:01 -07:00
parent a95454b6f3
commit eeadfa2d38
6 changed files with 150 additions and 28 deletions

View file

@ -42,6 +42,12 @@ func (g *irgen) stmt(stmt syntax.Stmt) ir.Node {
return x
case *syntax.SendStmt:
n := ir.NewSendStmt(g.pos(stmt), g.expr(stmt.Chan), g.expr(stmt.Value))
if n.Chan.Type().HasTParam() || n.Value.Type().HasTParam() {
// Delay transforming the send if the channel or value
// have a type param.
n.SetTypecheck(3)
return n
}
transformSend(n)
n.SetTypecheck(1)
return n
@ -118,6 +124,14 @@ func (g *irgen) stmt(stmt syntax.Stmt) ir.Node {
return ir.NewGoDeferStmt(g.pos(stmt), g.tokOp(int(stmt.Tok), callOps[:]), g.expr(stmt.Call))
case *syntax.ReturnStmt:
n := ir.NewReturnStmt(g.pos(stmt), g.exprList(stmt.Results))
for _, e := range n.Results {
if e.Type().HasTParam() {
// Delay transforming the return statement if any of the
// return values have a type param.
n.SetTypecheck(3)
return n
}
}
transformReturn(n)
n.SetTypecheck(1)
return n