commit 172bbe09cdfbe35aa61ea68b4a1fecc7189856f7
author Paul Berry <paulberry@google.com> Mon Jun 10 18:07:01 2024 +0000
committer Commit Queue <dart-scoped@luci-project-accounts.iam.gserviceaccount.com> Mon Jun 10 18:07:01 2024 +0000
tree acd37a914d1dfdf92992c81ed76e6a1585dac4e9
parent 8e219fcd089b6333d196a758f3a7f9b19292ae9a

Add type tracking to type inference logging.

This commit updates the type inference logging logic introduced in
https://dart-review.googlesource.com/c/sdk/+/369788 so that it
additionally tracks the context and static type for each inferred
expression.

Tracking the context for each expression is easy, since it is an input
to the type inference algorithm, passed in to each `visit` method of
`ResolverVisitor` through the named parameter `contextType`. However,
there were a few expression types for which the context type *wasn't*
passed in, because it wasn't used (for example
`ResolverVisitor.visitBooleanLiteral`, since boolean literals always
have the same meaning regardless of their context). `contextType`
parameters have been added to these `visit` methods for consistency
with the other expression visit methods, so that the type inference
log shows the context for all expressions, whether it makes a
difference to inference or not.

Tracking the static type for each expression is a little trickier,
since it's not an explicit output of the type inference algorithm, but
rather the static type of each expression is set as a side effect of
the type inference mechanism. To make things more tractable, the
`ExpressionImpl.staticType` field is made private, and instead of
setting it directly, the resolver must set it by either calling
`recordStaticType` or `setPseudoExpressionStaticType`. The former is
used when resolving a real expression; the latter is used for
situations where the analyzer assigns a static type to an AST node
even though that AST node isn't really serving as an expression
according to the official language specification. (For example, when
analyzing the method invocation `x.foo()`, the analyzer stores a
static type on the SimpleIdentifier `foo`, even though according to
the language spec, `foo` in this context actually isn't an expression
in its own right).

Splitting the code paths that set static types into `recordStaticType`
and `setPseudoExpressionStaticType` allows for the type inference
logging mechanism to check some useful invariants: it verifies that
every expression that the resolver visits is either assigned a static
type exactly once through a call to `recordStaticType`, or it's
determined to not be a true expression (and hence not assigned a
static type at all); I believe the latter happens mostly when
analyzing erroneous code, or when the resolver visitor is called upon
to assign a type to an identifier that's in a declaration context.

Change-Id: Icdf023d03fba3c87dbec3a72d00d0e9c7d1da5fa
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/370322
Reviewed-by: Chloe Stefantsova <cstefantsova@google.com>
Commit-Queue: Paul Berry <paulberry@google.com>
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>