16034193780

Committed 02 Jul 2025 07:37PM UTC coverage: 37.619% (+0.3%) from 37.308%

Build # 16034193780

Build Type

Pull #17

github

Committed by

haveyaseen

Commit Message

fix(typechecker): implement proper nested field path traversal for shape guards

The typechecker was failing to handle nested field access with dot notation (e.g., op.input.name) in shape guards and other contexts. The root cause was that field lookup functions were not properly handling multi-segment field names and were incorrectly recursing into nested shapes for single-segment lookups.

This commit adds new path-aware field lookup functions (lookupFieldPath, lookupFieldPathOnShape, lookupFieldPathOnMergedFields) that properly handle dot notation by splitting field names and recursively traversing the path. The existing field lookup functions have been updated to use these new functions where appropriate, ensuring consistent behavior across type definitions, assertions, and variable lookups.

The fix specifically addresses the bug where looking up a field like "input" in a shape containing {input: {name: String}} would incorrectly try to find "input" in the nested shape instead of returning the shape type. For multi-segment paths like "input.name", the new logic properly splits the path and recurses into the nested shape to find "name".

All typechecker tests now pass, confirming that nested field access works correctly for shape guards and other use cases. The shape guard feature can now properly handle expressions like op.input.name where op is a shape with nested fields.

Pull Request Pull Request #17: feat: Shape guards

Run Details

1757 of 4800 new or added lines in 83 files covered. (36.6%)

89 existing lines in 29 files now uncovered.

3081 of 8190 relevant lines covered (37.62%)

6.35 hits per line

Source File
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59.26

/forst/internal/parser/scope_stack.go

package parser

import (
        "github.com/sirupsen/logrus"
)

// ScopeStack manages a stack of scopes during type checking
type ScopeStack struct {
        scopes  []*Scope
        current *Scope
        log     *logrus.Logger
}

// NewScopeStack creates a new stack with a global scope
func NewScopeStack(log *logrus.Logger) *ScopeStack {
        globalScope := NewScope("", true, false, log)
        scopes := []*Scope{globalScope}
        return &ScopeStack{
                scopes:  scopes,
                current: globalScope,
                log:     log,
        }
}

// PushScope creates and pushes a new scope for the given AST node
func (ss *ScopeStack) PushScope(scope *Scope) {
        if scope.IsGlobal {
                ss.log.Fatalf("Cannot push global scope")
        }
        ss.scopes = append(ss.scopes, scope)
        ss.current = scope
}

func (ss *ScopeStack) PopScope() {
        if ss.current.IsGlobal {
                ss.log.Fatalf("Cannot pop global scope")
        }
        ss.scopes = ss.scopes[:len(ss.scopes)-1]
        ss.current = ss.scopes[len(ss.scopes)-1]
}

func (ss *ScopeStack) CurrentScope() *Scope {
        return ss.current
}

func (ss *ScopeStack) GlobalScope() *Scope {
        return ss.scopes[0]
}

1	package parser
2
3	import (
4	"github.com/sirupsen/logrus"
5	)
6
7	// ScopeStack manages a stack of scopes during type checking
8	type ScopeStack struct {
9	scopes []*Scope
10	current *Scope
11	log *logrus.Logger
12	}
13
14	// NewScopeStack creates a new stack with a global scope
15	func NewScopeStack(log logrus.Logger) ScopeStack {	63✔
16	globalScope := NewScope("", true, false, log)	63✔
17	scopes := []*Scope{globalScope}	63✔
18	return &ScopeStack{	63✔
19	scopes: scopes,	63✔
20	current: globalScope,	63✔
21	log: log,	63✔
22	}	63✔
23	}	63✔
24
25	// PushScope creates and pushes a new scope for the given AST node
26	func (ss ScopeStack) PushScope(scope Scope) {	31✔
27	if scope.IsGlobal {	31✔
NEW 28	ss.log.Fatalf("Cannot push global scope")	×
NEW 29	}	×
30	ss.scopes = append(ss.scopes, scope)	31✔
31	ss.current = scope	31✔
32	}
33
NEW 34	func (ss *ScopeStack) PopScope() {	×
NEW 35	if ss.current.IsGlobal {	×
NEW 36	ss.log.Fatalf("Cannot pop global scope")	×
NEW 37	}	×
NEW 38	ss.scopes = ss.scopes[:len(ss.scopes)-1]	×
NEW 39	ss.current = ss.scopes[len(ss.scopes)-1]	×
40	}
41
42	func (ss ScopeStack) CurrentScope() Scope {	30✔
43	return ss.current	30✔
44	}	30✔
45
NEW 46	func (ss ScopeStack) GlobalScope() Scope {	×
NEW 47	return ss.scopes[0]	×
NEW 48	}	×

forst-lang / forst / 16034193780

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