[compiler][newinference] Explicitly model StoreContext variables as mutable boxes #33465
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…utable boxes
Context variables — in the {Declare,Store,Load}Context sense — are conceptually like mutable boxes that are stored into and read out of at various points. Previously some fixtures were failing in the new inference bc i wasn't fully modeling them this way, so this PR moves toward more explicitly modeling these variables exactly like a mutable object that we're storing into and reading out of.
One catch is that unlike with regular variables, a `StoreContext Let x = ...` may not be the initial declaration of a value — for hoisted bindings, they may be a `DeclareContext HoistedLet x` first. So we first do a scan over the HIR to determine which declaration ids have hoisted let/const/function bindings. Then we model the "first" declaration of each context declaration id as the creation of fresh mutable value (box), then model subsequent reassignments as mutations of that box plus capturing of a value into that box, and model loads as CreateFrom from the box. Thus StoreContext assignments have equivalent effects to PropertyStore and LoadContext has equivalent effects to PropertyLoad.
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…utable boxes
Context variables — in the {Declare,Store,Load}Context sense — are conceptually like mutable boxes that are stored into and read out of at various points. Previously some fixtures were failing in the new inference bc i wasn't fully modeling them this way, so this PR moves toward more explicitly modeling these variables exactly like a mutable object that we're storing into and reading out of.
One catch is that unlike with regular variables, a `StoreContext Let x = ...` may not be the initial declaration of a value — for hoisted bindings, they may be a `DeclareContext HoistedLet x` first. So we first do a scan over the HIR to determine which declaration ids have hoisted let/const/function bindings. Then we model the "first" declaration of each context declaration id as the creation of fresh mutable value (box), then model subsequent reassignments as mutations of that box plus capturing of a value into that box, and model loads as CreateFrom from the box. Thus StoreContext assignments have equivalent effects to PropertyStore and LoadContext has equivalent effects to PropertyLoad.
ghstack-source-id: 8b8a6e3
Pull Request resolved: #33465
…iables as mutable boxes"
Context variables — in the {Declare,Store,Load}Context sense — are conceptually like mutable boxes that are stored into and read out of at various points. Previously some fixtures were failing in the new inference bc i wasn't fully modeling them this way, so this PR moves toward more explicitly modeling these variables exactly like a mutable object that we're storing into and reading out of.
One catch is that unlike with regular variables, a `StoreContext Let x = ...` may not be the initial declaration of a value — for hoisted bindings, they may be a `DeclareContext HoistedLet x` first. So we first do a scan over the HIR to determine which declaration ids have hoisted let/const/function bindings. Then we model the "first" declaration of each context declaration id as the creation of fresh mutable value (box), then model subsequent reassignments as mutations of that box plus capturing of a value into that box, and model loads as CreateFrom from the box. Thus StoreContext assignments have equivalent effects to PropertyStore and LoadContext has equivalent effects to PropertyLoad.
[ghstack-poisoned]
This was referenced Jun 6, 2025
…iables as mutable boxes"
Context variables — in the {Declare,Store,Load}Context sense — are conceptually like mutable boxes that are stored into and read out of at various points. Previously some fixtures were failing in the new inference bc i wasn't fully modeling them this way, so this PR moves toward more explicitly modeling these variables exactly like a mutable object that we're storing into and reading out of.
One catch is that unlike with regular variables, a `StoreContext Let x = ...` may not be the initial declaration of a value — for hoisted bindings, they may be a `DeclareContext HoistedLet x` first. So we first do a scan over the HIR to determine which declaration ids have hoisted let/const/function bindings. Then we model the "first" declaration of each context declaration id as the creation of fresh mutable value (box), then model subsequent reassignments as mutations of that box plus capturing of a value into that box, and model loads as CreateFrom from the box. Thus StoreContext assignments have equivalent effects to PropertyStore and LoadContext has equivalent effects to PropertyLoad.
[ghstack-poisoned]
…iables as mutable boxes"
Context variables — in the {Declare,Store,Load}Context sense — are conceptually like mutable boxes that are stored into and read out of at various points. Previously some fixtures were failing in the new inference bc i wasn't fully modeling them this way, so this PR moves toward more explicitly modeling these variables exactly like a mutable object that we're storing into and reading out of.
One catch is that unlike with regular variables, a `StoreContext Let x = ...` may not be the initial declaration of a value — for hoisted bindings, they may be a `DeclareContext HoistedLet x` first. So we first do a scan over the HIR to determine which declaration ids have hoisted let/const/function bindings. Then we model the "first" declaration of each context declaration id as the creation of fresh mutable value (box), then model subsequent reassignments as mutations of that box plus capturing of a value into that box, and model loads as CreateFrom from the box. Thus StoreContext assignments have equivalent effects to PropertyStore and LoadContext has equivalent effects to PropertyLoad.
[ghstack-poisoned]
…iables as mutable boxes"
Context variables — in the {Declare,Store,Load}Context sense — are conceptually like mutable boxes that are stored into and read out of at various points. Previously some fixtures were failing in the new inference bc i wasn't fully modeling them this way, so this PR moves toward more explicitly modeling these variables exactly like a mutable object that we're storing into and reading out of.
One catch is that unlike with regular variables, a `StoreContext Let x = ...` may not be the initial declaration of a value — for hoisted bindings, they may be a `DeclareContext HoistedLet x` first. So we first do a scan over the HIR to determine which declaration ids have hoisted let/const/function bindings. Then we model the "first" declaration of each context declaration id as the creation of fresh mutable value (box), then model subsequent reassignments as mutations of that box plus capturing of a value into that box, and model loads as CreateFrom from the box. Thus StoreContext assignments have equivalent effects to PropertyStore and LoadContext has equivalent effects to PropertyLoad.
[ghstack-poisoned]
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Stack from ghstack (oldest at bottom):
Context variables — in the {Declare,Store,Load}Context sense — are conceptually like mutable boxes that are stored into and read out of at various points. Previously some fixtures were failing in the new inference bc i wasn't fully modeling them this way, so this PR moves toward more explicitly modeling these variables exactly like a mutable object that we're storing into and reading out of.
One catch is that unlike with regular variables, a
StoreContext Let x = ...may not be the initial declaration of a value — for hoisted bindings, they may be aDeclareContext HoistedLet xfirst. So we first do a scan over the HIR to determine which declaration ids have hoisted let/const/function bindings. Then we model the "first" declaration of each context declaration id as the creation of fresh mutable value (box), then model subsequent reassignments as mutations of that box plus capturing of a value into that box, and model loads as CreateFrom from the box. Thus StoreContext assignments have equivalent effects to PropertyStore and LoadContext has equivalent effects to PropertyLoad.