Don't set parent on non-transient symbols in mergeSymbolTable by jakebailey · Pull Request #61560 · microsoft/TypeScript

Jake Bailey (jakebailey) · 2025-04-09T20:38:36Z

This is functionally equivalent to the change made in microsoft/typescript-go#775; this line is stomping on real binder-created AST symbols, which is bad.

Jake Bailey (jakebailey) · 2025-04-09T20:39:23Z

TypeScript Bot (@typescript-bot) test it

TypeScript Bot (typescript-bot) · 2025-04-09T20:39:28Z

Starting jobs; this comment will be updated as builds start and complete.

Command	Status	Results
`test top400`	✅ Started	✅ Results
`user test this`	✅ Started	✅ Results
`run dt`	✅ Started	✅ Results
`perf test this faster`	✅ Started	👀 Results

TypeScript Bot (typescript-bot) · 2025-04-09T21:03:39Z

Hey Jake Bailey (@jakebailey), the results of running the DT tests are ready.

Everything looks the same!

You can check the log here.

TypeScript Bot (typescript-bot) · 2025-04-09T21:12:09Z

Jake Bailey (@jakebailey) Here are the results of running the user tests with tsc comparing main and refs/pull/61560/merge:

Everything looks good!

TypeScript Bot (typescript-bot) · 2025-04-09T21:27:15Z

Jake Bailey (@jakebailey)
The results of the perf run you requested are in!

Here they are:

tsc

Comparison Report - baseline..pr

_Metric	_baseline	_pr	_Delta	_Best	_Worst	_p-value
_{Compiler-Unions - node (v18.15.0, x64)}
_Errors	₃₄	₃₄	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_62,390	_62,390	_~	_~	_~	_{p=1.000 n=6}
_Types	_50,395	_50,395	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{194,137k (± 0.97%)}	_{193,691k (± 0.78%)}	_~	_192,906k	_196,758k	_{p=0.748 n=6}
_{Parse Time}	_{1.30s (± 0.84%)}	_{1.31s (± 0.57%)}	_~	_1.30s	_1.32s	_{p=0.227 n=6}
_{Bind Time}	_0.73s	_0.73s	_~	_~	_~	_{p=1.000 n=6}
_{Check Time}	_{9.74s (± 0.44%)}	_{9.74s (± 0.39%)}	_~	_9.69s	_9.80s	_{p=0.936 n=6}
_{Emit Time}	_{2.73s (± 0.30%)}	_{2.73s (± 1.01%)}	_~	_2.70s	_2.77s	_{p=0.805 n=6}
_{Total Time}	_{14.51s (± 0.37%)}	_{14.51s (± 0.38%)}	_~	_14.42s	_14.59s	_{p=0.747 n=6}
_{angular-1 - node (v18.15.0, x64)}
_Errors	₅₆	₅₆	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_948,670	_948,670	_~	_~	_~	_{p=1.000 n=6}
_Types	_410,947	_410,947	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{1,224,316k (± 0.00%)}	_{1,224,260k (± 0.00%)}	_~	_1,224,232k	_1,224,317k	_{p=0.092 n=6}
_{Parse Time}	_{6.64s (± 0.81%)}	_{6.66s (± 0.47%)}	_~	_6.60s	_6.68s	_{p=0.142 n=6}
_{Bind Time}	_{1.89s (± 0.62%)}	_{1.88s (± 0.62%)}	_~	_1.86s	_1.89s	_{p=0.187 n=6}
_{Check Time}	_{31.97s (± 0.22%)}	_{31.96s (± 0.37%)}	_~	_31.83s	_32.14s	_{p=0.810 n=6}
_{Emit Time}	_{15.28s (± 0.53%)}	_{15.25s (± 0.59%)}	_~	_15.14s	_15.36s	_{p=0.629 n=6}
_{Total Time}	_{55.78s (± 0.09%)}	_{55.75s (± 0.27%)}	_~	_55.55s	_55.96s	_{p=0.810 n=6}
_{mui-docs - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_2,462,748	_2,462,748	_~	_~	_~	_{p=1.000 n=6}
_Types	_893,580	_893,580	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{2,312,764k (± 0.00%)}	_{2,312,703k (± 0.00%)}	_~	_2,312,595k	_2,312,774k	_{p=0.261 n=6}
_{Parse Time}	_{9.10s (± 0.20%)}	_{9.09s (± 0.20%)}	_~	_9.08s	_9.12s	_{p=0.243 n=6}
_{Bind Time}	_{2.29s (± 0.53%)}	_{2.29s (± 0.64%)}	_~	_2.27s	_2.30s	_{p=0.867 n=6}
_{Check Time}	_{75.67s (± 0.48%)}	_{75.79s (± 0.50%)}	_~	_75.32s	_76.30s	_{p=0.810 n=6}
_{Emit Time}	_{0.29s (± 1.41%)}	_0.29s	_~	_~	_~	_{p=0.405 n=6}
_{Total Time}	_{87.36s (± 0.42%)}	_{87.46s (± 0.44%)}	_~	_86.96s	_87.99s	_{p=0.810 n=6}
_{self-build-src - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,226,719	_1,226,719	_~	_~	_~	_{p=1.000 n=6}
_Types	_266,996	_266,996	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{2,967,290k (±10.02%)}	_{2,846,187k (±13.21%)}	_~	_2,359,958k	_3,089,705k	_{p=1.000 n=6}
_{Parse Time}	_{6.72s (± 1.33%)}	_{6.66s (± 1.60%)}	_~	_6.52s	_6.78s	_{p=0.230 n=6}
_{Bind Time}	_{2.15s (± 2.59%)}	_{2.16s (± 0.94%)}	_~	_2.13s	_2.19s	_{p=0.748 n=6}
_{Check Time}	_{42.80s (± 0.23%)}	_{42.77s (± 0.38%)}	_~	_42.54s	_43.00s	_{p=1.000 n=6}
_{Emit Time}	_{3.48s (± 2.87%)}	_{3.39s (± 2.18%)}	_~	_3.32s	_3.51s	_{p=0.128 n=6}
_{Total Time}	_{55.15s (± 0.18%)}	_{55.00s (± 0.38%)}	_~	_54.75s	_55.37s	_{p=0.128 n=6}
_{self-build-src-public-api - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_1,226,719	_1,226,719	_~	_~	_~	_{p=1.000 n=6}
_Types	_266,996	_266,996	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{2,424,447k (± 0.01%)}	_{2,424,343k (± 0.02%)}	_~	_2,424,004k	_2,424,842k	_{p=0.810 n=6}
_{Parse Time}	_{5.47s (± 0.48%)}	_{5.49s (± 0.45%)}	_~	_5.45s	_5.51s	_{p=0.335 n=6}
_{Bind Time}	_{1.78s (± 1.15%)}	_{1.80s (± 1.26%)}	_~	_1.77s	_1.82s	_{p=0.252 n=6}
_{Check Time}	_{35.35s (± 0.23%)}	_{35.35s (± 0.22%)}	_~	_35.26s	_35.47s	_{p=0.936 n=6}
_{Emit Time}	_{3.06s (± 1.22%)}	_{3.06s (± 1.16%)}	_~	_3.01s	_3.09s	_{p=1.000 n=6}
_{Total Time}	_{45.69s (± 0.17%)}	_{45.72s (± 0.17%)}	_~	_45.60s	_45.80s	_{p=0.748 n=6}
_{self-compiler - node (v18.15.0, x64)}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_262,674	_262,674	_~	_~	_~	_{p=1.000 n=6}
_Types	_106,849	_106,849	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{440,427k (± 0.02%)}	_{440,445k (± 0.02%)}	_~	_440,324k	_440,508k	_{p=0.630 n=6}
_{Parse Time}	_{3.53s (± 1.27%)}	_{3.53s (± 0.86%)}	_~	_3.49s	_3.58s	_{p=0.935 n=6}
_{Bind Time}	_{1.31s (± 1.08%)}	_{1.32s (± 0.91%)}	_~	_1.31s	_1.34s	_{p=0.139 n=6}
_{Check Time}	_{18.98s (± 0.55%)}	_{18.95s (± 0.45%)}	_~	_18.80s	_19.01s	_{p=0.872 n=6}
_{Emit Time}	_{1.51s (± 0.68%)}	_{1.52s (± 1.25%)}	_~	_1.49s	_1.55s	_{p=0.094 n=6}
_{Total Time}	_{25.32s (± 0.46%)}	_{25.32s (± 0.44%)}	_~	_25.15s	_25.41s	_{p=0.936 n=6}
_{ts-pre-modules - node (v18.15.0, x64)}
_Errors	₇₁	₇₁	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_225,981	_225,981	_~	_~	_~	_{p=1.000 n=6}
_Types	_94,356	_94,356	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{371,236k (± 0.04%)}	_{371,221k (± 0.02%)}	_~	_371,125k	_371,333k	_{p=0.575 n=6}
_{Parse Time}	_{2.88s (± 0.56%)}	_{2.91s (± 0.73%)}	_{+0.03s (+ 1.04%)}	_2.88s	_2.94s	_{p=0.034 n=6}
_{Bind Time}	_{1.59s (± 0.65%)}	_{1.61s (± 1.41%)}	_~	_1.58s	_1.64s	_{p=0.217 n=6}
_{Check Time}	_{16.52s (± 0.39%)}	_{16.53s (± 0.30%)}	_~	_16.48s	_16.62s	_{p=0.936 n=6}
_{Emit Time}	_{0.00s (±244.70%)}	_0.00s	_~	_~	_~	_{p=0.405 n=6}
_{Total Time}	_{21.00s (± 0.37%)}	_{21.05s (± 0.30%)}	_~	_20.98s	_21.15s	_{p=0.170 n=6}
_{vscode - node (v18.15.0, x64)}
_Errors	₄	₄	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_3,344,528	_3,344,528	_~	_~	_~	_{p=1.000 n=6}
_Types	_1,133,660	_1,133,660	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{3,404,018k (± 0.01%)}	_{3,403,860k (± 0.00%)}	_~	_3,403,629k	_3,404,141k	_{p=0.128 n=6}
_{Parse Time}	_{14.72s (± 0.62%)}	_{14.73s (± 0.33%)}	_~	_14.67s	_14.79s	_{p=0.936 n=6}
_{Bind Time}	_{4.69s (± 0.60%)}	_{4.74s (± 2.01%)}	_~	_4.68s	_4.93s	_{p=0.294 n=6}
_{Check Time}	_{92.41s (± 1.52%)}	_{91.20s (± 0.45%)}	_~	_90.52s	_91.67s	_{p=0.054 n=6}
_{Emit Time}	_{29.61s (± 1.68%)}	_{29.75s (± 2.23%)}	_~	_29.32s	_31.04s	_{p=0.936 n=6}
_{Total Time}	_{141.43s (± 0.87%)}	_{140.40s (± 0.42%)}	_~	_139.85s	_141.22s	_{p=0.093 n=6}
_{webpack - node (v18.15.0, x64)}
_Errors	₂	₂	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_312,525	_312,525	_~	_~	_~	_{p=1.000 n=6}
_Types	_137,826	_137,826	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{467,643k (± 0.02%)}	_{467,593k (± 0.03%)}	_~	_467,436k	_467,760k	_{p=0.378 n=6}
_{Parse Time}	_{5.14s (± 1.15%)}	_{5.12s (± 1.13%)}	_~	_5.07s	_5.23s	_{p=0.683 n=6}
_{Bind Time}	_{2.27s (± 0.72%)}	_{2.25s (± 1.42%)}	_~	_2.21s	_2.30s	_{p=0.126 n=6}
_{Check Time}	_{25.59s (± 0.20%)}	_{25.51s (± 0.21%)}	_{-0.08s (- 0.32%)}	_25.44s	_25.58s	_{p=0.030 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{33.01s (± 0.28%)}	_{32.89s (± 0.27%)}	_~	_32.78s	_33.00s	_{p=0.066 n=6}
_{xstate-main - node (v18.15.0, x64)}
_Errors	₅	₅	_~	_~	_~	_{p=1.000 n=6}
_Symbols	_568,548	_568,548	_~	_~	_~	_{p=1.000 n=6}
_Types	_190,459	_190,459	_~	_~	_~	_{p=1.000 n=6}
_{Memory used}	_{498,525k (± 0.01%)}	_{498,465k (± 0.01%)}	_~	_498,414k	_498,558k	_{p=0.093 n=6}
_{Parse Time}	_{3.37s (± 0.83%)}	_{3.36s (± 0.83%)}	_~	_3.31s	_3.38s	_{p=0.936 n=6}
_{Bind Time}	_{1.20s (± 0.86%)}	_{1.21s (± 1.10%)}	_~	_1.19s	_1.23s	_{p=0.506 n=6}
_{Check Time}	_{20.00s (± 0.35%)}	_{20.03s (± 0.31%)}	_~	_19.97s	_20.11s	_{p=0.296 n=6}
_{Emit Time}	_0.00s	_0.00s	_~	_~	_~	_{p=1.000 n=6}
_{Total Time}	_{24.57s (± 0.32%)}	_{24.60s (± 0.30%)}	_~	_24.49s	_24.70s	_{p=0.470 n=6}

System info unknown

Hosts

node (v18.15.0, x64)

Scenarios

Compiler-Unions - node (v18.15.0, x64)
angular-1 - node (v18.15.0, x64)
mui-docs - node (v18.15.0, x64)
self-build-src - node (v18.15.0, x64)
self-build-src-public-api - node (v18.15.0, x64)
self-compiler - node (v18.15.0, x64)
ts-pre-modules - node (v18.15.0, x64)
vscode - node (v18.15.0, x64)
webpack - node (v18.15.0, x64)
xstate-main - node (v18.15.0, x64)

_Benchmark	_Name	_Iterations
_Current	_pr	₆
_Baseline	_baseline	₆

Developer Information:

Download Benchmarks

TypeScript Bot (typescript-bot) · 2025-04-09T22:11:40Z

Jake Bailey (@jakebailey) Here are the results of running the top 400 repos with tsc comparing main and refs/pull/61560/merge:

Everything looks good!

Copilot

Pull Request Overview

This PR fixes an issue where mergeSymbolTable was incorrectly setting the parent property on non-transient symbols, which overwrites proper binder-created AST symbols. The change adds a guard to only set the parent on transient symbols.

Don't set parent on non-transient symbols in mergeSymbolTable

0efb559

github-project-automation Bot added this to PR Backlog Apr 9, 2025

github-project-automation Bot moved this to Not started in PR Backlog Apr 9, 2025

TypeScript Bot (typescript-bot) assigned Jake Bailey (jakebailey) Apr 9, 2025

TypeScript Bot (typescript-bot) added Author: Team For Uncommitted Bug PR for untriaged, rejected, closed or missing bug labels Apr 9, 2025

Jake Bailey (jakebailey) requested review from Daniel Rosenwasser (DanielRosenwasser) and Anders Hejlsberg (ahejlsberg) June 30, 2025 23:34

Merge branch 'main' into transient-symbol-merge

e2105d5

Copilot AI review requested due to automatic review settings September 11, 2025 00:11

Copilot AI reviewed Sep 11, 2025

View reviewed changes

Comment thread src/compiler/checker.ts

Ryan Cavanaugh (RyanCavanaugh) approved these changes Dec 4, 2025

View reviewed changes

github-project-automation Bot moved this from Not started to Needs merge in PR Backlog Dec 4, 2025

Jake Bailey (jakebailey) merged commit b33d372 into microsoft:main Dec 4, 2025
33 checks passed

github-project-automation Bot moved this from Needs merge to Done in PR Backlog Dec 4, 2025

Jake Bailey (jakebailey) deleted the transient-symbol-merge branch December 4, 2025 17:47

Microsoft (microsoft) locked as resolved and limited conversation to collaborators Jun 3, 2026

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Don't set parent on non-transient symbols in mergeSymbolTable - #61560

Don't set parent on non-transient symbols in mergeSymbolTable#61560
Jake Bailey (jakebailey) merged 2 commits into
microsoft:mainfrom
jakebailey:transient-symbol-merge

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