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ahejlsbergahejlsberg
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Fix over-eager isMatchingConstructorReference function (#4691)
1 parent cc49daf commit dc8e6a8

4 files changed

Lines changed: 160 additions & 5 deletions

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‎internal/checker/flow.go‎

Lines changed: 6 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -736,12 +736,13 @@ func (c *Checker) narrowTypeByDiscriminant(t *Type, access *ast.Node, narrowType
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}
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738738
func (c *Checker) isMatchingConstructorReference(f *FlowState, expr *ast.Node) bool {
739-
if ast.IsAccessExpression(expr) {
740-
if accessedName, ok := c.getAccessedPropertyName(expr); ok && accessedName == "constructor" && c.isMatchingReference(f.reference, expr.Expression()) {
741-
return true
742-
}
739+
var name *ast.Node
740+
if ast.IsPropertyAccessExpression(expr) {
741+
name = expr.AsPropertyAccessExpression().Name()
742+
} else if ast.IsElementAccessExpression(expr) && ast.IsStringLiteralLike(expr.AsElementAccessExpression().ArgumentExpression) {
743+
name = expr.AsElementAccessExpression().ArgumentExpression
743744
}
744-
return false
745+
return name != nil && name.Text() == "constructor" && c.isMatchingReference(f.reference, expr.Expression())
745746
}
746747

747748
func (c *Checker) narrowTypeByConstructor(t *Type, operator ast.Kind, identifier *ast.Node, assumeTrue bool) *Type {

‎testdata/baselines/reference/compiler/controlFlowNoCircularity.symbols‎

Lines changed: 56 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,56 @@
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//// [tests/cases/compiler/controlFlowNoCircularity.ts] ////
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=== controlFlowNoCircularity.ts ===
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// https://github.com/microsoft/typescript-go/issues/4673
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export function repro(board: number[][], pos: number | undefined): void {
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>repro : Symbol(repro, Decl(controlFlowNoCircularity.ts, 0, 0))
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>board : Symbol(board, Decl(controlFlowNoCircularity.ts, 2, 22))
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>pos : Symbol(pos, Decl(controlFlowNoCircularity.ts, 2, 40))
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if (!pos) return;
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>pos : Symbol(pos, Decl(controlFlowNoCircularity.ts, 2, 40))
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for (const pattern of [{ target: [-1, -1], intermediate: [-1, 0] }]) {
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>pattern : Symbol(pattern, Decl(controlFlowNoCircularity.ts, 4, 12))
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>target : Symbol(target, Decl(controlFlowNoCircularity.ts, 4, 26))
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>intermediate : Symbol(intermediate, Decl(controlFlowNoCircularity.ts, 4, 44))
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const targetR = pos + pattern.target[0];
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>targetR : Symbol(targetR, Decl(controlFlowNoCircularity.ts, 5, 9))
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>pos : Symbol(pos, Decl(controlFlowNoCircularity.ts, 2, 40))
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>pattern.target : Symbol(target, Decl(controlFlowNoCircularity.ts, 4, 26))
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>pattern : Symbol(pattern, Decl(controlFlowNoCircularity.ts, 4, 12))
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>target : Symbol(target, Decl(controlFlowNoCircularity.ts, 4, 26))
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const targetC = pos + pattern.target[1];
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>targetC : Symbol(targetC, Decl(controlFlowNoCircularity.ts, 6, 9))
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>pos : Symbol(pos, Decl(controlFlowNoCircularity.ts, 2, 40))
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>pattern.target : Symbol(target, Decl(controlFlowNoCircularity.ts, 4, 26))
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>pattern : Symbol(pattern, Decl(controlFlowNoCircularity.ts, 4, 12))
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>target : Symbol(target, Decl(controlFlowNoCircularity.ts, 4, 26))
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if (board[targetR][targetC] !== 0) {}
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>board : Symbol(board, Decl(controlFlowNoCircularity.ts, 2, 22))
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>targetR : Symbol(targetR, Decl(controlFlowNoCircularity.ts, 5, 9))
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>targetC : Symbol(targetC, Decl(controlFlowNoCircularity.ts, 6, 9))
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const [ir, ic] = pattern.intermediate;
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>ir : Symbol(ir, Decl(controlFlowNoCircularity.ts, 8, 11))
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>ic : Symbol(ic, Decl(controlFlowNoCircularity.ts, 8, 14))
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>pattern.intermediate : Symbol(intermediate, Decl(controlFlowNoCircularity.ts, 4, 44))
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>pattern : Symbol(pattern, Decl(controlFlowNoCircularity.ts, 4, 12))
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>intermediate : Symbol(intermediate, Decl(controlFlowNoCircularity.ts, 4, 44))
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const midC = ic;
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>midC : Symbol(midC, Decl(controlFlowNoCircularity.ts, 9, 9))
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>ic : Symbol(ic, Decl(controlFlowNoCircularity.ts, 8, 14))
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49+
if (board[ir][midC] === 0) {
50+
>board : Symbol(board, Decl(controlFlowNoCircularity.ts, 2, 22))
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>ir : Symbol(ir, Decl(controlFlowNoCircularity.ts, 8, 11))
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>midC : Symbol(midC, Decl(controlFlowNoCircularity.ts, 9, 9))
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}
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}
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}
56+

‎testdata/baselines/reference/compiler/controlFlowNoCircularity.types‎

Lines changed: 82 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,82 @@
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//// [tests/cases/compiler/controlFlowNoCircularity.ts] ////
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=== controlFlowNoCircularity.ts ===
4+
// https://github.com/microsoft/typescript-go/issues/4673
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export function repro(board: number[][], pos: number | undefined): void {
7+
>repro : (board: number[][], pos: number | undefined) => void
8+
>board : number[][]
9+
>pos : number | undefined
10+
11+
if (!pos) return;
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>!pos : boolean
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>pos : number | undefined
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for (const pattern of [{ target: [-1, -1], intermediate: [-1, 0] }]) {
16+
>pattern : { target: number[]; intermediate: number[]; }
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>[{ target: [-1, -1], intermediate: [-1, 0] }] : { target: number[]; intermediate: number[]; }[]
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>{ target: [-1, -1], intermediate: [-1, 0] } : { target: number[]; intermediate: number[]; }
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>target : number[]
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>[-1, -1] : number[]
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>-1 : -1
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>1 : 1
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>-1 : -1
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>1 : 1
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>intermediate : number[]
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>[-1, 0] : number[]
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>-1 : -1
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>1 : 1
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>0 : 0
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const targetR = pos + pattern.target[0];
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>targetR : number
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>pos + pattern.target[0] : number
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>pos : number
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>pattern.target[0] : number
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>pattern.target : number[]
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>pattern : { target: number[]; intermediate: number[]; }
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>target : number[]
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>0 : 0
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const targetC = pos + pattern.target[1];
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>targetC : number
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>pos + pattern.target[1] : number
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>pos : number
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>pattern.target[1] : number
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>pattern.target : number[]
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>pattern : { target: number[]; intermediate: number[]; }
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>target : number[]
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>1 : 1
50+
51+
if (board[targetR][targetC] !== 0) {}
52+
>board[targetR][targetC] !== 0 : boolean
53+
>board[targetR][targetC] : number
54+
>board[targetR] : number[]
55+
>board : number[][]
56+
>targetR : number
57+
>targetC : number
58+
>0 : 0
59+
60+
const [ir, ic] = pattern.intermediate;
61+
>ir : number
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>ic : number
63+
>pattern.intermediate : number[]
64+
>pattern : { target: number[]; intermediate: number[]; }
65+
>intermediate : number[]
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67+
const midC = ic;
68+
>midC : number
69+
>ic : number
70+
71+
if (board[ir][midC] === 0) {
72+
>board[ir][midC] === 0 : boolean
73+
>board[ir][midC] : number
74+
>board[ir] : number[]
75+
>board : number[][]
76+
>ir : number
77+
>midC : number
78+
>0 : 0
79+
}
80+
}
81+
}
82+

‎testdata/tests/cases/compiler/controlFlowNoCircularity.ts‎

Lines changed: 16 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,16 @@
1+
// @noEmit: true
2+
3+
// https://github.com/microsoft/typescript-go/issues/4673
4+
5+
export function repro(board: number[][], pos: number | undefined): void {
6+
if (!pos) return;
7+
for (const pattern of [{ target: [-1, -1], intermediate: [-1, 0] }]) {
8+
const targetR = pos + pattern.target[0];
9+
const targetC = pos + pattern.target[1];
10+
if (board[targetR][targetC] !== 0) {}
11+
const [ir, ic] = pattern.intermediate;
12+
const midC = ic;
13+
if (board[ir][midC] === 0) {
14+
}
15+
}
16+
}

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