Switch to `type SymbolName unique.Handle[string]` by jakebailey · Pull Request #64699 · microsoft/TypeScript

Jake Bailey (jakebailey) · 2026-10-08T21:59:08Z

Symbol names are currently plain strings. Every identifier, symbol, symbol table key, and name-keyed cache holds its own 16-byte string header, every lookup hashes and compares the full text, and all of those pointers have to be scanned by the GC. On large projects that adds up to a lot of memory and GC work for what is effectively a small set of repeated names.

This PR interns symbol names instead:

ast.SymbolName is now a 32-bit ID into a process-wide, pointer-free intern table, so names cost 4 bytes, compare and hash as integers, and are invisible to the GC.
Identifiers are interned once in the parser and the name is stored on Identifier, so the binder, checker, and language service use it directly rather than reinterning node text on each lookup. The AST schema gains a SymbolName type; the JS API still sees strings.
A small per-parser cache lets repeated identifiers in a file skip the shared table.

Perf run: 3.7–13.4% less memory across the suite, mui-docs 10% faster, bind 18–24% faster, and no total-time regressions. Parse is 8–15% slower from hashing each identifier.

Interned names are never freed. That's bounded per program for tsc, but the table grows over a long language server session.

Jake Bailey (jakebailey) · 2026-10-08T21:59:46Z

TypeScript Bot (@typescript-bot) perf test this

typescript-automation · 2026-10-08T21:59:53Z

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

Command	Status	Results
`perf test this`	✅ Started	👀 Results

typescript-automation · 2026-10-08T22:31:24Z

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 - native}
_Errors	₄₁	₄₁	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_115,276	_115,276	_~	_~	_~	_{p=1.000 n=12}
_Types	_79,613	_79,613	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{135,310k (± 0.08%)}	_{134,555k (± 0.05%)}	_{-754k (- 0.56%)}	_134,394k	_134,762k	_{p=0.000 n=12}
_{Memory Allocs}	_{2,190,636 (± 0.00%)}	_{2,279,198 (± 0.05%)}	_{🔻+88,562 (+ 4.04%)}	_2,275,969	_2,282,067	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.050s (± 2.84%)}	_{0.049s (± 3.22%)}	_~	_0.044s	_0.053s	_{p=0.502 n=12}
_{Bind Time}	_{0.015s (±13.33%)}	_{0.030s (± 7.99%)}	_{🔻+0.015s (+99.45%)}	_0.026s	_0.036s	_{p=0.000 n=12}
_{Check Time}	_{0.615s (± 0.71%)}	_{0.612s (± 0.92%)}	_~	_0.602s	_0.630s	_{p=0.162 n=12}
_{Emit Time}	_{0.329s (± 2.14%)}	_{0.338s (± 1.22%)}	_{+0.009s (+ 2.68%)}	_0.324s	_0.348s	_{p=0.034 n=12}
_{Total Time}	_{1.018s (± 0.96%)}	_{1.037s (± 0.62%)}	_{+0.019s (+ 1.88%)}	_1.021s	_1.057s	_{p=0.001 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{845,989 (± 0.05%)}	_{845,729 (± 0.09%)}	_~	_842,740	_847,317	_{p=0.932 n=12}
_Types	_{248,124 (± 0.00%)}	_{248,123 (± 0.00%)}	_~	_248,122	_248,125	_{p=0.993 n=12}
_{Memory Used}	_{764,653k (± 0.02%)}	_{746,535k (± 0.02%)}	_{-18,119k (- 2.37%)}	_746,119k	_746,997k	_{p=0.000 n=12}
_{Memory Allocs}	_{12,925,262 (± 0.06%)}	_{13,352,078 (± 0.04%)}	_{+426,816 (+ 3.30%)}	_13,345,546	_13,372,669	_{p=0.000 n=12}
_{Config Time}	_{0.016s (± 1.97%)}	_{0.017s (± 1.07%)}	_{+0.001s (+ 3.05%)}	_0.016s	_0.017s	_{p=0.027 n=12}
_{Parse Time}	_{0.257s (± 2.58%)}	_{0.259s (± 2.82%)}	_~	_0.234s	_0.268s	_{p=0.385 n=12}
_{Bind Time}	_{0.063s (±12.33%)}	_{0.100s (±10.80%)}	_{🔻+0.037s (+59.92%)}	_0.092s	_0.150s	_{p=0.000 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.587s (± 1.21%)}	_{1.626s (± 0.86%)}	_{+0.039s (+ 2.45%)}	_1.594s	_1.679s	_{p=0.004 n=12}
_{Total Time}	_{1.937s (± 1.28%)}	_{2.014s (± 0.99%)}	_{+0.076s (+ 3.94%)}	_1.979s	_2.101s	_{p=0.000 n=12}
_{mui-docs - native}
_Errors	_11,405	_11,405	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_4,359,614	_4,359,614	_~	_~	_~	_{p=1.000 n=12}
_Types	_1,376,379	_1,376,379	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{2,874,210k (± 0.05%)}	_{2,568,218k (± 0.05%)}	_{🟩-305,992k (-10.65%)}	_2,564,693k	_2,571,397k	_{p=0.000 n=12}
_{Memory Allocs}	_{32,870,213 (± 0.08%)}	_{33,621,012 (± 0.06%)}	_{+750,799 (+ 2.28%)}	_33,575,749	_33,692,494	_{p=0.000 n=12}
_{Config Time}	_{0.020s (± 1.21%)}	_{0.020s (± 1.52%)}	_~	_0.020s	_0.021s	_{p=0.640 n=12}
_{Parse Time}	_{0.624s (± 2.60%)}	_{0.604s (± 2.39%)}	_{🟩-0.020s (- 3.14%)}	_0.568s	_0.640s	_{p=0.050 n=12}
_{Bind Time}	_{0.003s (±13.14%)}	_{0.003s (±12.54%)}	_~	_0.002s	_0.003s	_{p=1.000 n=12}
_{Check Time}	_{10.344s (± 0.63%)}	_{9.367s (± 0.38%)}	_{🟩-0.977s (- 9.44%)}	_9.291s	_9.463s	_{p=0.000 n=12}
_{Emit Time}	_{0.510s (± 1.88%)}	_{0.513s (± 1.14%)}	_~	_0.505s	_0.535s	_{p=0.199 n=12}
_{Total Time}	_{12.430s (± 0.51%)}	_{11.545s (± 0.32%)}	_{🟩-0.886s (- 7.12%)}	_11.449s	_11.644s	_{p=0.000 n=12}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,390,229	_1,390,229	_~	_~	_~	_{p=1.000 n=12}
_Types	_441,498	_441,498	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{1,641,820k (± 0.88%)}	_{1,623,524k (± 0.28%)}	_{-18,296k (- 1.11%)}	_1,612,197k	_1,634,391k	_{p=0.028 n=12}
_{Memory Allocs}	_{92,093,413 (± 0.16%)}	_{95,246,262 (± 0.15%)}	_{+3,152,849 (+ 3.42%)}	_94,939,040	_95,592,937	_{p=0.000 n=12}
_{Config Time}	_{0.003s (±14.60%)}	_{0.003s (±14.59%)}	_~	_0.002s	_0.004s	_{p=0.784 n=12}
_{Parse Time}	_{0.191s (± 4.22%)}	_{0.188s (± 2.57%)}	_~	_0.176s	_0.199s	_{p=0.639 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.820s (± 0.66%)}	_{1.888s (± 0.45%)}	_{+0.068s (+ 3.72%)}	_1.869s	_1.908s	_{p=0.000 n=12}
_{Emit Time}	_{0.305s (± 5.01%)}	_{0.321s (± 4.73%)}	_~	_0.283s	_0.372s	_{p=0.173 n=12}
_{Total Time}	_{23.652s (± 0.97%)}	_{24.999s (± 0.56%)}	_{🔻+1.347s (+ 5.70%)}	_24.737s	_25.487s	_{p=0.000 n=12}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_334,953	_334,953	_~	_~	_~	_{p=1.000 n=12}
_Types	_197,616	_197,616	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{302,588k (± 0.03%)}	_{299,768k (± 0.02%)}	_{-2,820k (- 0.93%)}	_299,594k	_299,874k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,622,914 (± 0.01%)}	_{4,830,806 (± 0.01%)}	_{🔻+207,892 (+ 4.50%)}	_4,830,094	_4,831,876	_{p=0.000 n=12}
_{Config Time}	_{0.001s (±29.38%)}	_{0.001s (±65.70%)}	_~	_0.000s	_0.001s	_{p=0.193 n=12}
_{Parse Time}	_{0.092s (± 5.04%)}	_{0.095s (± 4.82%)}	_~	_0.083s	_0.110s	_{p=0.223 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{0.878s (± 0.68%)}	_{0.912s (± 0.42%)}	_{+0.034s (+ 3.83%)}	_0.900s	_0.920s	_{p=0.000 n=12}
_{Emit Time}	_{0.109s (±10.35%)}	_{0.124s (± 6.74%)}	_{🔻+0.015s (+13.72%)}	_0.098s	_0.140s	_{p=0.013 n=12}
_{Total Time}	_{1.121s (± 1.06%)}	_{1.201s (± 1.07%)}	_{🔻+0.081s (+ 7.20%)}	_1.160s	_1.235s	_{p=0.000 n=12}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_303,834	_303,834	_~	_~	_~	_{p=1.000 n=12}
_Types	_181,663	_181,663	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{263,493k (± 0.02%)}	_{260,182k (± 0.02%)}	_{-3,311k (- 1.26%)}	_259,924k	_260,272k	_{p=0.000 n=12}
_{Memory Allocs}	_{1,616,022 (± 0.01%)}	_{1,791,998 (± 0.01%)}	_{🔻+175,976 (+10.89%)}	_1,791,727	_1,792,462	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.099s (± 3.19%)}	_{0.098s (± 4.94%)}	_~	_0.089s	_0.108s	_{p=0.832 n=12}
_{Bind Time}	_{0.037s (± 9.76%)}	_{0.070s (± 7.91%)}	_{🔻+0.034s (+90.97%)}	_0.058s	_0.081s	_{p=0.000 n=12}
_{Check Time}	_{0.829s (± 0.76%)}	_{0.860s (± 0.82%)}	_{+0.031s (+ 3.69%)}	_0.844s	_0.878s	_{p=0.000 n=12}
_{Emit Time}	_{0.000s (±217.90%)}	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.981s (± 0.53%)}	_{1.043s (± 0.71%)}	_{🔻+0.062s (+ 6.29%)}	_1.026s	_1.069s	_{p=0.000 n=12}
_{vscode - native}
_Errors	₃₈₀	₃₈₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_11,126,412	_11,126,412	_~	_~	_~	_{p=1.000 n=12}
_Types	_3,695,451	_3,695,451	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{6,709,468k (± 0.02%)}	_{6,472,806k (± 0.02%)}	_{🟩-236,662k (- 3.53%)}	_6,468,963k	_6,477,601k	_{p=0.000 n=12}
_{Memory Allocs}	_{54,762,461 (± 0.03%)}	_{56,714,048 (± 0.02%)}	_{+1,951,587 (+ 3.56%)}	_56,703,781	_56,758,908	_{p=0.000 n=12}
_{Config Time}	_{0.073s (± 0.56%)}	_{0.074s (± 0.44%)}	_{+0.001s (+ 1.48%)}	_0.074s	_0.075s	_{p=0.000 n=12}
_{Parse Time}	_{1.812s (± 3.88%)}	_{1.836s (± 3.66%)}	_~	_1.672s	_2.035s	_{p=0.671 n=12}
_{Bind Time}	_{0.622s (±18.49%)}	_{0.831s (±15.00%)}	_{🔻+0.209s (+33.64%)}	_0.690s	_1.232s	_{p=0.018 n=12}
_{Check Time}	_{13.958s (± 1.17%)}	_{14.712s (± 0.99%)}	_{🔻+0.753s (+ 5.40%)}	_14.238s	_14.937s	_{p=0.000 n=12}
_{Emit Time}	_{4.908s (±12.67%)}	_{4.654s (± 8.71%)}	_~	_4.184s	_6.004s	_{p=0.443 n=12}
_{Total Time}	_{21.463s (± 2.41%)}	_{22.186s (± 1.51%)}	_~	_21.711s	_23.306s	_{p=0.143 n=12}
_{webpack - native}
_Errors	₅₈₉	₅₈₉	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,304,270	_1,304,270	_~	_~	_~	_{p=1.000 n=12}
_Types	_618,461	_618,461	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{958,988k (± 0.01%)}	_{925,774k (± 0.02%)}	_{🟩-33,214k (- 3.46%)}	_925,297k	_926,313k	_{p=0.000 n=12}
_{Memory Allocs}	_{6,606,657 (± 0.01%)}	_{7,086,476 (± 0.04%)}	_{🔻+479,819 (+ 7.26%)}	_7,081,900	_7,094,237	_{p=0.000 n=12}
_{Config Time}	_0.009s	_0.009s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.288s (± 3.23%)}	_{0.291s (± 3.25%)}	_~	_0.267s	_0.319s	_{p=0.744 n=12}
_{Bind Time}	_{0.086s (±20.33%)}	_{0.128s (±10.05%)}	_{🔻+0.042s (+49.03%)}	_0.107s	_0.177s	_{p=0.001 n=12}
_{Check Time}	_{2.073s (± 1.02%)}	_{2.127s (± 0.88%)}	_{+0.054s (+ 2.62%)}	_2.073s	_2.162s	_{p=0.001 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{2.491s (± 0.52%)}	_{2.591s (± 0.63%)}	_{🔻+0.101s (+ 4.03%)}	_2.558s	_2.639s	_{p=0.000 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,055,452	_1,055,452	_~	_~	_~	_{p=1.000 n=12}
_Types	_386,738	_386,738	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{570,764k (± 0.03%)}	_{545,375k (± 0.03%)}	_{🟩-25,389k (- 4.45%)}	_545,072k	_545,991k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,859,932 (± 0.08%)}	_{5,156,372 (± 0.09%)}	_{🔻+296,440 (+ 6.10%)}	_5,146,655	_5,173,137	_{p=0.000 n=12}
_{Config Time}	_{0.003s (± 6.23%)}	_{0.003s (± 6.23%)}	_~	_0.002s	_0.003s	_{p=1.000 n=12}
_{Parse Time}	_{0.143s (± 2.40%)}	_{0.145s (± 3.12%)}	_~	_0.131s	_0.154s	_{p=0.416 n=12}
_{Bind Time}	_{0.044s (±21.01%)}	_{0.090s (±12.08%)}	_{🔻+0.046s (+104.91%)}	_0.066s	_0.111s	_{p=0.000 n=12}
_{Check Time}	_{1.128s (± 0.48%)}	_{1.130s (± 0.74%)}	_~	_1.112s	_1.164s	_{p=0.660 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.324s (± 0.56%)}	_{1.374s (± 0.76%)}	_{+0.050s (+ 3.78%)}	_1.344s	_1.394s	_{p=0.000 n=12}

System info unknown

Hosts

native

Scenarios

Compiler-Unions - native
angular-1 - native
mui-docs - native
strada-build-src - native
strada-compiler - native
ts-pre-modules - native
vscode - native
webpack - native
xstate-main - native

_Benchmark	_Name	_Iterations
_Current	_pr	₁₂
_Baseline	_baseline	₁₂

lsp

Comparison Report - baseline..pr

_Metric	_baseline	_pr	_Delta	_Best	_Worst	_p-value
_{Compiler-UnionsLSP - native}
_{Req 1 - updateOpen}	_{13ms (±10.94%)}	_{14ms (±10.03%)}	_~	_11ms	_17ms	_{p=0.513 n=12}
_{Req 2 - geterr}	_{699ms (± 0.41%)}	_{709ms (± 0.64%)}	_{+9ms (+ 1.33%)}	_697ms	_717ms	_{p=0.002 n=12}
_{Req 3 - references}	_{53ms (± 4.78%)}	_{52ms (± 7.15%)}	_~	_43ms	_62ms	_{p=0.382 n=12}
_{Req 4 - navto}	_{20ms (± 3.00%)}	_{20ms (± 6.07%)}	_~	_18ms	_26ms	_{p=0.383 n=12}
_{Req 5 - completionInfo count}	_1,363	_1,363	_~	_~	_~	_{p=1.000 n=12}
_{Req 5 - completionInfo}	_{20ms (± 7.01%)}	_{20ms (±11.54%)}	_~	_16ms	_30ms	_{p=0.136 n=12}
_{CompilerLSP - native}
_{Req 1 - updateOpen}	_{12ms (±13.27%)}	_{11ms (±10.67%)}	_~	_10ms	_15ms	_{p=1.000 n=12}
_{Req 2 - geterr}	_{298ms (± 0.64%)}	_{318ms (± 0.60%)}	_{🔻+20ms (+ 6.76%)}	_313ms	_324ms	_{p=0.000 n=12}
_{Req 3 - references}	_{50ms (± 3.62%)}	_{49ms (± 4.22%)}	_~	_44ms	_54ms	_{p=0.678 n=12}
_{Req 4 - navto}	_{17ms (± 3.43%)}	_{17ms (± 2.54%)}	_~	_15ms	_17ms	_{p=0.167 n=12}
_{Req 5 - completionInfo count}	_1,525	_1,525	_~	_~	_~	_{p=1.000 n=12}
_{Req 5 - completionInfo}	_{17ms (± 6.11%)}	_{17ms (± 6.98%)}	_~	_15ms	_21ms	_{p=0.741 n=12}

System info unknown

Hosts

native

Scenarios

CompilerLSP - native
Compiler-UnionsLSP - native
xstate-main-1-LSP - native

_Benchmark	_Name	_Iterations
_Current	_pr	₁₂
_Baseline	_baseline	₁₂

startup

Comparison Report - baseline..pr

_Metric	_baseline	_pr	_Delta	_Best	_Worst	_p-value
_{lsp-startup - native}
_{Execution time}	_{4.80ms (±365.08%)}	_{4.83ms (±365.09%)}	_{+0.03ms (+ 0.62%)}	_0.00ms	_491.10ms	_{p=0.000 n=1200}
_{tsgo-startup - native}
_{Execution time}	_{5.83ms (±365.09%)}	_{5.88ms (±365.08%)}	_{+0.04ms (+ 0.73%)}	_0.00ms	_593.40ms	_{p=0.000 n=1200}

System info unknown

Hosts

native

Scenarios

lsp-startup - native
tsgo-startup - native

_Benchmark	_Name	_Iterations
_Current	_pr	₁₂
_Baseline	_baseline	₁₂

Developer Information:

Download Benchmarks

Symbols should share canonical names so identity checks and symbol-table lookups do not repeatedly compare string contents. Preserve textual behavior for diagnostics, emitted output, and the JavaScript API.

Known names and intermediate name operations should stay interned; repeated interning and string round trips defeat the canonical representation in frequently used lookup paths.

Symbol names need their own constructor and representation boundary, without exposing generic string handles throughout the compiler. Give name serialization a lossless escaped spelling and distinguish unset names from valid empty names.

unique.Make registers a weak handle for every new string, which made binding substantially slower and added allocations. Canonical names do not need to be collected during a compilation, so a dedicated table can make interning cheap. Identifying names by a 32-bit ID also keeps them free of pointers, so the symbol tables, nodes, and caches that store them cost the garbage collector nothing to scan or write-barrier.

Binding, checking, and language features reinterned identifier text at every symbol-table lookup, so interning cost was paid many times per identifier and showed up as a large binding regression. Interning once when the identifier is created lets every later lookup use the stored name directly. The AST schema gains a SymbolName field type so the generated Go AST and encoder carry the interned name while the JavaScript API still sees a plain string.

Most identifiers in a file repeat a small set of names, and going to the shared intern table for each one makes parsing noticeably slower, especially when many files are parsed in parallel. A small per-parser cache resolves repeated names without touching shared state.

Jake Bailey (jakebailey) · 2026-10-15T17:22:10Z

TypeScript Bot (@typescript-bot) perf test this faster

typescript-automation · 2026-10-15T17:22:16Z

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

Command	Status	Results
`perf test this faster`	✅ Started	👀 Results

typescript-automation · 2026-10-15T17:52:21Z

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 - native}
_Errors	₄₁	₄₁	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_115,276	_115,276	_~	_~	_~	_{p=1.000 n=12}
_Types	_79,613	_79,613	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{113,479k (± 0.05%)}	_{109,247k (± 0.06%)}	_{🟩-4,232k (- 3.73%)}	_109,072k	_109,388k	_{p=0.000 n=12}
_{Memory Allocs}	_{2,212,486 (± 0.01%)}	_{2,220,023 (± 0.01%)}	_{+7,536 (+ 0.34%)}	_2,219,635	_2,220,280	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.039s (± 4.40%)}	_{0.044s (± 3.77%)}	_{🔻+0.005s (+13.03%)}	_0.040s	_0.048s	_{p=0.000 n=12}
_{Bind Time}	_{0.013s (±10.03%)}	_{0.013s (± 8.82%)}	_~	_0.010s	_0.017s	_{p=0.395 n=12}
_{Check Time}	_{0.467s (± 0.43%)}	_{0.456s (± 0.84%)}	_{-0.010s (- 2.23%)}	_0.448s	_0.465s	_{p=0.000 n=12}
_{Emit Time}	_{0.265s (± 1.66%)}	_{0.267s (± 1.43%)}	_~	_0.258s	_0.276s	_{p=0.579 n=12}
_{Total Time}	_{0.791s (± 0.67%)}	_{0.786s (± 0.42%)}	_~	_0.781s	_0.795s	_{p=0.103 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{847,026 (± 0.07%)}	_{847,024 (± 0.11%)}	_~	_844,638	_849,050	_{p=0.887 n=12}
_Types	_{247,032 (± 0.00%)}	_{247,032 (± 0.00%)}	_~	_247,030	_247,042	_{p=0.548 n=12}
_{Memory Used}	_{596,379k (± 0.03%)}	_{560,230k (± 0.03%)}	_{🟩-36,149k (- 6.06%)}	_559,817k	_560,650k	_{p=0.000 n=12}
_{Memory Allocs}	_{13,149,404 (± 0.09%)}	_{13,172,319 (± 0.05%)}	_{+22,915 (+ 0.17%)}	_13,168,352	_13,205,949	_{p=0.001 n=12}
_{Config Time}	_{0.017s (± 1.45%)}	_{0.017s (± 1.07%)}	_~	_0.016s	_0.017s	_{p=1.000 n=12}
_{Parse Time}	_{0.221s (± 2.54%)}	_{0.245s (± 4.57%)}	_{🔻+0.024s (+10.71%)}	_0.220s	_0.283s	_{p=0.000 n=12}
_{Bind Time}	_{0.088s (±13.82%)}	_{0.067s (±15.71%)}	_{🟩-0.021s (-24.22%)}	_0.056s	_0.100s	_{p=0.005 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.559s (± 1.24%)}	_{1.532s (± 1.28%)}	_{-0.027s (- 1.74%)}	_1.484s	_1.597s	_{p=0.046 n=12}
_{Total Time}	_{1.904s (± 0.95%)}	_{1.874s (± 1.06%)}	_{-0.031s (- 1.61%)}	_1.811s	_1.922s	_{p=0.020 n=12}
_{mui-docs - native}
_Errors	_11,405	_11,405	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_4,331,835	_4,331,835	_~	_~	_~	_{p=1.000 n=12}
_Types	_1,370,520	_1,370,520	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{2,626,589k (± 0.07%)}	_{2,273,471k (± 0.08%)}	_{🟩-353,118k (-13.44%)}	_2,269,818k	_2,278,100k	_{p=0.000 n=12}
_{Memory Allocs}	_{27,705,934 (± 0.05%)}	_{27,696,753 (± 0.06%)}	_~	_27,658,960	_27,747,847	_{p=0.551 n=12}
_{Config Time}	_{0.017s (± 1.86%)}	_0.017s	_~	_~	_~	_{p=0.093 n=12}
_{Parse Time}	_{0.468s (± 3.07%)}	_{0.476s (± 4.02%)}	_~	_0.429s	_0.513s	_{p=0.451 n=12}
_{Bind Time}	_0.002s	_{0.002s (± 9.47%)}	_~	_0.001s	_0.002s	_{p=1.000 n=12}
_{Check Time}	_{7.273s (± 0.66%)}	_{6.394s (± 0.42%)}	_{🟩-0.879s (-12.09%)}	_6.365s	_6.491s	_{p=0.000 n=12}
_{Emit Time}	_{0.497s (±11.53%)}	_{0.461s (± 2.62%)}	_~	_0.420s	_0.472s	_{p=0.787 n=12}
_{Total Time}	_{8.998s (± 0.74%)}	_{8.100s (± 0.22%)}	_{🟩-0.897s (- 9.97%)}	_8.055s	_8.145s	_{p=0.000 n=12}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,388,669	_1,388,669	_~	_~	_~	_{p=1.000 n=12}
_Types	_441,862	_441,862	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{1,317,489k (± 0.62%)}	_{1,250,199k (± 0.49%)}	_{🟩-67,289k (- 5.11%)}	_1,232,740k	_1,272,021k	_{p=0.000 n=12}
_{Memory Allocs}	_{78,188,492 (± 0.06%)}	_{78,316,018 (± 0.15%)}	_{+127,526 (+ 0.16%)}	_77,974,859	_78,560,994	_{p=0.020 n=12}
_{Config Time}	_{0.003s (± 8.75%)}	_{0.006s (±13.52%)}	_{🔻+0.003s (+97.44%)}	_0.004s	_0.009s	_{p=0.000 n=12}
_{Parse Time}	_{0.252s (± 3.11%)}	_{0.279s (± 1.60%)}	_{🔻+0.027s (+10.74%)}	_0.267s	_0.291s	_{p=0.000 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{1.677s (± 0.53%)}	_{1.617s (± 0.39%)}	_{🟩-0.061s (- 3.61%)}	_1.596s	_1.633s	_{p=0.000 n=12}
_{Emit Time}	_{0.297s (± 3.44%)}	_{0.284s (± 3.71%)}	_~	_0.253s	_0.310s	_{p=0.061 n=12}
_{Total Time}	_{19.834s (± 0.51%)}	_{19.290s (± 0.58%)}	_{-0.544s (- 2.74%)}	_19.005s	_19.590s	_{p=0.000 n=12}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_334,953	_334,953	_~	_~	_~	_{p=1.000 n=12}
_Types	_197,616	_197,616	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{247,512k (± 0.03%)}	_{235,878k (± 0.03%)}	_{🟩-11,634k (- 4.70%)}	_235,668k	_236,047k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,329,530 (± 0.01%)}	_{4,347,875 (± 0.01%)}	_{+18,345 (+ 0.42%)}	_4,346,250	_4,348,965	_{p=0.000 n=12}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.111s (± 5.77%)}	_{0.127s (± 2.34%)}	_{🔻+0.016s (+14.15%)}	_0.118s	_0.134s	_{p=0.000 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{0.961s (± 0.56%)}	_{0.945s (± 0.48%)}	_{-0.016s (- 1.65%)}	_0.933s	_0.957s	_{p=0.000 n=12}
_{Emit Time}	_{0.145s (± 4.78%)}	_{0.149s (± 3.81%)}	_~	_0.129s	_0.161s	_{p=0.522 n=12}
_{Total Time}	_{1.273s (± 0.77%)}	_{1.273s (± 0.60%)}	_~	_1.251s	_1.288s	_{p=0.744 n=12}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_303,834	_303,834	_~	_~	_~	_{p=1.000 n=12}
_Types	_181,663	_181,663	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{215,246k (± 0.02%)}	_{204,557k (± 0.02%)}	_{🟩-10,689k (- 4.97%)}	_204,473k	_204,646k	_{p=0.000 n=12}
_{Memory Allocs}	_{1,401,509 (± 0.01%)}	_{1,417,139 (± 0.02%)}	_{+15,630 (+ 1.12%)}	_1,416,670	_1,417,761	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.096s (± 3.98%)}	_{0.110s (± 4.09%)}	_{🔻+0.015s (+15.16%)}	_0.099s	_0.121s	_{p=0.000 n=12}
_{Bind Time}	_{0.043s (± 8.47%)}	_{0.039s (±10.15%)}	_~	_0.032s	_0.051s	_{p=0.102 n=12}
_{Check Time}	_{0.747s (± 0.83%)}	_{0.729s (± 0.88%)}	_{-0.017s (- 2.33%)}	_0.715s	_0.743s	_{p=0.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.900s (± 0.64%)}	_{0.893s (± 0.77%)}	_~	_0.876s	_0.909s	_{p=0.181 n=12}
_{vscode - native}
_Errors	₃₉₆	₃₉₆	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_11,850,414	_11,850,414	_~	_~	_~	_{p=1.000 n=12}
_Types	_3,908,124	_3,908,124	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{5,600,881k (± 0.02%)}	_{5,216,068k (± 0.03%)}	_{🟩-384,813k (- 6.87%)}	_5,213,135k	_5,220,738k	_{p=0.000 n=12}
_{Memory Allocs}	_{57,029,448 (± 0.10%)}	_{57,054,527 (± 0.02%)}	_{+25,079 (+ 0.04%)}	_57,033,205	_57,086,847	_{p=0.000 n=12}
_{Config Time}	_{0.075s (± 0.43%)}	_{0.076s (± 0.86%)}	_~	_0.075s	_0.079s	_{p=0.150 n=12}
_{Parse Time}	_{1.754s (± 2.09%)}	_{1.903s (± 2.04%)}	_{🔻+0.149s (+ 8.49%)}	_1.774s	_2.010s	_{p=0.000 n=12}
_{Bind Time}	_{0.669s (±13.18%)}	_{0.549s (±13.23%)}	_{🟩-0.120s (-17.90%)}	_0.472s	_0.807s	_{p=0.010 n=12}
_{Check Time}	_{14.650s (± 0.74%)}	_{14.531s (± 0.84%)}	_~	_14.190s	_14.751s	_{p=0.514 n=12}
_{Emit Time}	_{5.671s (± 7.34%)}	_{5.544s (± 6.48%)}	_~	_4.461s	_6.013s	_{p=0.561 n=12}
_{Total Time}	_{22.911s (± 1.46%)}	_{22.686s (± 1.56%)}	_~	_21.652s	_23.230s	_{p=0.347 n=12}
_{webpack - native}
_Errors	₅₈₄	₅₈₄	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,297,360	_1,297,360	_~	_~	_~	_{p=1.000 n=12}
_Types	_593,542	_593,542	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{784,599k (± 0.03%)}	_{731,203k (± 0.03%)}	_{🟩-53,396k (- 6.81%)}	_730,793k	_731,773k	_{p=0.000 n=12}
_{Memory Allocs}	_{6,034,028 (± 0.06%)}	_{6,068,414 (± 0.04%)}	_{+34,386 (+ 0.57%)}	_6,063,913	_6,075,621	_{p=0.000 n=12}
_{Config Time}	_0.009s	_{0.009s (± 2.00%)}	_~	_0.009s	_0.010s	_{p=1.000 n=12}
_{Parse Time}	_{0.302s (± 3.50%)}	_{0.306s (± 2.98%)}	_~	_0.279s	_0.338s	_{p=0.560 n=12}
_{Bind Time}	_{0.074s (± 3.57%)}	_{0.075s (± 8.70%)}	_~	_0.064s	_0.095s	_{p=0.560 n=12}
_{Check Time}	_{2.133s (± 0.60%)}	_{2.055s (± 0.43%)}	_{🟩-0.077s (- 3.63%)}	_2.032s	_2.077s	_{p=0.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{2.554s (± 0.65%)}	_{2.483s (± 0.57%)}	_{-0.070s (- 2.75%)}	_2.457s	_2.528s	_{p=0.000 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,062,854	_1,062,854	_~	_~	_~	_{p=1.000 n=12}
_Types	_390,845	_390,845	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{472,259k (± 0.02%)}	_{434,074k (± 0.03%)}	_{🟩-38,185k (- 8.09%)}	_433,757k	_434,462k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,223,835 (± 0.07%)}	_{4,245,930 (± 0.06%)}	_{+22,095 (+ 0.52%)}	_4,238,989	_4,253,061	_{p=0.000 n=12}
_{Config Time}	_{0.003s (± 6.23%)}	_{0.003s (± 8.64%)}	_~	_0.002s	_0.003s	_{p=1.000 n=12}
_{Parse Time}	_{0.133s (± 3.58%)}	_{0.148s (± 2.41%)}	_{🔻+0.014s (+10.75%)}	_0.138s	_0.156s	_{p=0.000 n=12}
_{Bind Time}	_{0.049s (±18.00%)}	_{0.039s (±11.68%)}	_~	_0.032s	_0.051s	_{p=0.074 n=12}
_{Check Time}	_{1.010s (± 0.74%)}	_{0.966s (± 0.87%)}	_{🟩-0.044s (- 4.36%)}	_0.946s	_0.989s	_{p=0.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{1.202s (± 0.48%)}	_{1.164s (± 0.70%)}	_{🟩-0.038s (- 3.13%)}	_1.141s	_1.177s	_{p=0.000 n=12}

System info unknown

Hosts

native

Scenarios

Compiler-Unions - native
angular-1 - native
mui-docs - native
strada-build-src - native
strada-compiler - native
ts-pre-modules - native
vscode - native
webpack - native
xstate-main - native

_Benchmark	_Name	_Iterations
_Current	_pr	₁₂
_Baseline	_baseline	₁₂

Developer Information:

Download Benchmarks

Interning every identifier at parse time hashes its text, but the scanner has just walked the same bytes. Hashing while scanning saves a second pass over each identifier in the parser's hottest path. │ sec/op │ sec/op vs base │ Parse/empty.ts-20 610.1n ± 2% 610.2n ± 1% ~ (p=0.767 n=12) Parse/checker.ts-20 46.61m ± 3% 45.68m ± 3% -1.99% (p=0.005 n=12) Parse/dom.generated.d.ts-20 16.71m ± 2% 16.53m ± 3% ~ (p=0.178 n=12) Parse/Herebyfile.mjs-20 786.8µ ± 2% 779.4µ ± 1% ~ (p=0.319 n=12) Parse/jsxComplexSignatureHasApplicabilityError.tsx-20 218.6µ ± 2% 213.3µ ± 2% -2.41% (p=0.012 n=12) geomean 606.0µ 598.2µ -1.29%

Jake Bailey (jakebailey) · 2026-10-15T19:22:12Z

TypeScript Bot (@typescript-bot) perf test this faster

typescript-automation · 2026-10-15T19:22:19Z

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

Command	Status	Results
`perf test this faster`	✅ Started	👀 Results

typescript-automation · 2026-10-15T19:55:31Z

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 - native}
_Errors	₄₁	₄₁	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_115,276	_115,276	_~	_~	_~	_{p=1.000 n=12}
_Types	_79,613	_79,613	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{113,544k (± 0.07%)}	_{109,252k (± 0.04%)}	_{🟩-4,292k (- 3.78%)}	_109,128k	_109,360k	_{p=0.000 n=12}
_{Memory Allocs}	_{2,212,499 (± 0.01%)}	_{2,220,006 (± 0.01%)}	_{+7,508 (+ 0.34%)}	_2,219,689	_2,220,362	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.038s (± 4.50%)}	_{0.043s (± 2.88%)}	_{🔻+0.005s (+13.63%)}	_0.040s	_0.046s	_{p=0.000 n=12}
_{Bind Time}	_{0.014s (± 9.15%)}	_{0.012s (± 7.92%)}	_~	_0.011s	_0.015s	_{p=0.138 n=12}
_{Check Time}	_{0.469s (± 0.80%)}	_{0.452s (± 0.62%)}	_{🟩-0.016s (- 3.45%)}	_0.446s	_0.461s	_{p=0.000 n=12}
_{Emit Time}	_{0.269s (± 2.12%)}	_{0.269s (± 2.28%)}	_~	_0.254s	_0.285s	_{p=0.944 n=12}
_{Total Time}	_{0.796s (± 0.90%)}	_{0.784s (± 0.73%)}	_{-0.012s (- 1.54%)}	_0.769s	_0.799s	_{p=0.011 n=12}
_{angular-1 - native}
_Errors	₃	₃	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_{847,116 (± 0.08%)}	_{847,194 (± 0.08%)}	_~	_845,430	_848,650	_{p=0.887 n=12}
_Types	_{247,033 (± 0.00%)}	_{247,032 (± 0.00%)}	_~	_247,030	_247,034	_{p=0.390 n=12}
_{Memory Used}	_{596,464k (± 0.02%)}	_{560,313k (± 0.03%)}	_{🟩-36,151k (- 6.06%)}	_559,807k	_560,648k	_{p=0.000 n=12}
_{Memory Allocs}	_{13,143,148 (± 0.05%)}	_{13,173,236 (± 0.04%)}	_{+30,088 (+ 0.23%)}	_13,166,102	_13,191,128	_{p=0.000 n=12}
_{Config Time}	_{0.020s (± 1.40%)}	_{0.021s (± 6.20%)}	_~	_0.020s	_0.025s	_{p=0.443 n=12}
_{Parse Time}	_{0.286s (± 2.63%)}	_{0.310s (± 2.80%)}	_{🔻+0.024s (+ 8.36%)}	_0.288s	_0.326s	_{p=0.000 n=12}
_{Bind Time}	_{0.108s (±12.71%)}	_{0.095s (±13.89%)}	_~	_0.076s	_0.135s	_{p=0.190 n=12}
_{Check Time}	_0s	_0s	_~	_~	_~	_{p=1.000 n=12}
_{Emit Time}	_{1.907s (± 1.25%)}	_{1.928s (± 2.31%)}	_~	_1.782s	_2.037s	_{p=0.284 n=12}
_{Total Time}	_{2.344s (± 1.13%)}	_{2.374s (± 1.89%)}	_~	_2.211s	_2.471s	_{p=0.117 n=12}
_{mui-docs - native}
_Errors	_11,405	_11,405	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_4,331,835	_4,331,835	_~	_~	_~	_{p=1.000 n=12}
_Types	_1,370,520	_1,370,520	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{2,625,369k (± 0.06%)}	_{2,272,617k (± 0.07%)}	_{🟩-352,751k (-13.44%)}	_2,268,756k	_2,277,064k	_{p=0.000 n=12}
_{Memory Allocs}	_{27,722,151 (± 0.14%)}	_{27,711,856 (± 0.13%)}	_~	_27,664,278	_27,886,220	_{p=0.551 n=12}
_{Config Time}	_{0.020s (± 1.59%)}	_{0.020s (± 0.90%)}	_~	_0.020s	_0.021s	_{p=0.155 n=12}
_{Parse Time}	_{0.593s (± 3.32%)}	_{0.604s (± 2.86%)}	_~	_0.551s	_0.655s	_{p=0.124 n=12}
_{Bind Time}	_{0.003s (± 8.64%)}	_{0.002s (±13.40%)}	_~	_0.002s	_0.003s	_{p=0.089 n=12}
_{Check Time}	_{8.655s (± 0.16%)}	_{7.611s (± 0.46%)}	_{🟩-1.043s (-12.06%)}	_7.572s	_7.740s	_{p=0.000 n=12}
_{Emit Time}	_{0.750s (± 8.09%)}	_{0.565s (± 3.04%)}	_{🟩-0.184s (-24.57%)}	_0.506s	_0.583s	_{p=0.000 n=12}
_{Total Time}	_{10.937s (± 0.67%)}	_{9.717s (± 0.28%)}	_{🟩-1.220s (-11.15%)}	_9.639s	_9.792s	_{p=0.000 n=12}
_{strada-build-src - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,388,669	_1,388,669	_~	_~	_~	_{p=1.000 n=12}
_Types	_441,862	_441,862	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{1,318,031k (± 0.91%)}	_{1,249,734k (± 0.54%)}	_{🟩-68,297k (- 5.18%)}	_1,234,336k	_1,275,228k	_{p=0.000 n=12}
_{Memory Allocs}	_{78,217,623 (± 0.06%)}	_{78,188,817 (± 0.17%)}	_~	_77,764,171	_78,445,656	_{p=0.755 n=12}
_{Config Time}	_{0.004s (± 9.20%)}	_{0.008s (±18.01%)}	_{🔻+0.004s (+90.20%)}	_0.005s	_0.012s	_{p=0.000 n=12}
_{Parse Time}	_{0.308s (± 2.05%)}	_{0.327s (± 1.92%)}	_{🔻+0.019s (+ 6.25%)}	_0.309s	_0.341s	_{p=0.001 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{2.000s (± 0.55%)}	_{1.934s (± 0.36%)}	_{🟩-0.066s (- 3.31%)}	_1.916s	_1.949s	_{p=0.000 n=12}
_{Emit Time}	_{0.342s (± 3.89%)}	_{0.342s (± 1.98%)}	_~	_0.328s	_0.361s	_{p=0.745 n=12}
_{Total Time}	_{23.672s (± 0.48%)}	_{23.174s (± 0.55%)}	_{-0.498s (- 2.10%)}	_22.829s	_23.533s	_{p=0.000 n=12}
_{strada-compiler - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_334,953	_334,953	_~	_~	_~	_{p=1.000 n=12}
_Types	_197,616	_197,616	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{247,527k (± 0.03%)}	_{235,858k (± 0.03%)}	_{🟩-11,669k (- 4.71%)}	_235,696k	_236,027k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,329,509 (± 0.01%)}	_{4,347,864 (± 0.01%)}	_{+18,355 (+ 0.42%)}	_4,346,840	_4,349,273	_{p=0.000 n=12}
_{Config Time}	_0.001s	_0.001s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.113s (± 5.39%)}	_{0.128s (± 3.31%)}	_{🔻+0.015s (+13.03%)}	_0.110s	_0.137s	_{p=0.001 n=12}
_{Bind Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Check Time}	_{0.962s (± 0.72%)}	_{0.950s (± 0.61%)}	_{-0.013s (- 1.30%)}	_0.935s	_0.969s	_{p=0.002 n=12}
_{Emit Time}	_{0.147s (± 7.01%)}	_{0.143s (± 4.22%)}	_~	_0.126s	_0.156s	_{p=0.854 n=12}
_{Total Time}	_{1.276s (± 1.00%)}	_{1.273s (± 0.82%)}	_~	_1.236s	_1.294s	_{p=1.000 n=12}
_{ts-pre-modules - native}
_Errors	₈₇	₈₇	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_303,834	_303,834	_~	_~	_~	_{p=1.000 n=12}
_Types	_181,663	_181,663	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{215,249k (± 0.02%)}	_{204,556k (± 0.02%)}	_{🟩-10,693k (- 4.97%)}	_204,493k	_204,649k	_{p=0.000 n=12}
_{Memory Allocs}	_{1,401,614 (± 0.01%)}	_{1,417,302 (± 0.01%)}	_{+15,688 (+ 1.12%)}	_1,416,588	_1,417,751	_{p=0.000 n=12}
_{Config Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.080s (± 4.55%)}	_{0.085s (± 3.45%)}	_{🔻+0.005s (+ 6.88%)}	_0.077s	_0.094s	_{p=0.023 n=12}
_{Bind Time}	_{0.034s (± 7.66%)}	_{0.030s (±10.12%)}	_~	_0.023s	_0.037s	_{p=0.066 n=12}
_{Check Time}	_{0.617s (± 0.86%)}	_{0.607s (± 1.27%)}	_{-0.011s (- 1.75%)}	_0.593s	_0.632s	_{p=0.016 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.743s (± 0.73%)}	_{0.734s (± 1.15%)}	_{-0.009s (- 1.22%)}	_0.721s	_0.764s	_{p=0.027 n=12}
_{vscode - native}
_Errors	₃₉₆	₃₉₆	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_11,858,782	_11,858,782	_~	_~	_~	_{p=1.000 n=12}
_Types	_3,913,076	_3,913,076	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{5,602,594k (± 0.02%)}	_{5,217,111k (± 0.02%)}	_{🟩-385,483k (- 6.88%)}	_5,214,586k	_5,220,496k	_{p=0.000 n=12}
_{Memory Allocs}	_{57,046,573 (± 0.00%)}	_{57,097,906 (± 0.02%)}	_{+51,333 (+ 0.09%)}	_57,077,234	_57,127,863	_{p=0.000 n=12}
_{Config Time}	_{0.075s (± 0.70%)}	_{0.075s (± 0.33%)}	_~	_0.075s	_0.076s	_{p=1.000 n=12}
_{Parse Time}	_{1.812s (± 2.12%)}	_{1.923s (± 2.43%)}	_{🔻+0.111s (+ 6.13%)}	_1.725s	_2.029s	_{p=0.001 n=12}
_{Bind Time}	_{0.573s (±10.43%)}	_{0.501s (±12.43%)}	_{🟩-0.072s (-12.56%)}	_0.452s	_0.814s	_{p=0.000 n=12}
_{Check Time}	_{14.773s (± 1.06%)}	_{14.516s (± 0.63%)}	_~	_14.125s	_14.686s	_{p=0.097 n=12}
_{Emit Time}	_{5.620s (± 6.22%)}	_{5.089s (± 6.75%)}	_{🟩-0.530s (- 9.44%)}	_4.394s	_6.185s	_{p=0.028 n=12}
_{Total Time}	_{22.940s (± 1.16%)}	_{22.183s (± 1.51%)}	_{🟩-0.757s (- 3.30%)}	_21.501s	_23.093s	_{p=0.002 n=12}
_{webpack - native}
_Errors	₅₈₄	₅₈₄	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,286,346	_1,286,346	_~	_~	_~	_{p=1.000 n=12}
_Types	_586,899	_586,899	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{775,946k (± 0.02%)}	_{724,486k (± 0.01%)}	_{🟩-51,460k (- 6.63%)}	_724,244k	_724,703k	_{p=0.000 n=12}
_{Memory Allocs}	_{5,993,657 (± 0.03%)}	_{6,030,764 (± 0.02%)}	_{+37,106 (+ 0.62%)}	_6,028,538	_6,035,314	_{p=0.000 n=12}
_{Config Time}	_0.009s	_0.009s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.309s (± 2.75%)}	_{0.311s (± 3.07%)}	_~	_0.292s	_0.343s	_{p=0.810 n=12}
_{Bind Time}	_{0.068s (± 1.94%)}	_{0.069s (± 3.98%)}	_~	_0.065s	_0.080s	_{p=0.897 n=12}
_{Check Time}	_{1.953s (± 0.29%)}	_{1.878s (± 0.40%)}	_{🟩-0.074s (- 3.82%)}	_1.854s	_1.895s	_{p=0.000 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{2.373s (± 0.50%)}	_{2.302s (± 0.55%)}	_{-0.071s (- 2.98%)}	_2.280s	_2.343s	_{p=0.000 n=12}
_{xstate-main - native}
_Errors	₀	₀	_~	_~	_~	_{p=1.000 n=12}
_Symbols	_1,062,854	_1,062,854	_~	_~	_~	_{p=1.000 n=12}
_Types	_390,845	_390,845	_~	_~	_~	_{p=1.000 n=12}
_{Memory Used}	_{472,425k (± 0.04%)}	_{434,137k (± 0.02%)}	_{🟩-38,288k (- 8.10%)}	_433,890k	_434,373k	_{p=0.000 n=12}
_{Memory Allocs}	_{4,228,361 (± 0.09%)}	_{4,250,806 (± 0.07%)}	_{+22,444 (+ 0.53%)}	_4,241,973	_4,259,903	_{p=0.000 n=12}
_{Config Time}	_0.002s	_0.002s	_~	_~	_~	_{p=1.000 n=12}
_{Parse Time}	_{0.103s (± 2.19%)}	_{0.115s (± 2.65%)}	_{🔻+0.011s (+11.03%)}	_0.108s	_0.122s	_{p=0.000 n=12}
_{Bind Time}	_{0.039s (±15.90%)}	_{0.029s (±14.67%)}	_{🟩-0.010s (-25.91%)}	_0.025s	_0.047s	_{p=0.001 n=12}
_{Check Time}	_{0.827s (± 0.99%)}	_{0.806s (± 1.27%)}	_{-0.021s (- 2.51%)}	_0.786s	_0.842s	_{p=0.002 n=12}
_{Emit Time}	_0.000s	_0.000s	_~	_~	_~	_{p=1.000 n=12}
_{Total Time}	_{0.978s (± 1.16%)}	_{0.958s (± 1.18%)}	_{-0.020s (- 2.08%)}	_0.935s	_0.991s	_{p=0.014 n=12}

System info unknown

Hosts

native

Scenarios

Compiler-Unions - native
angular-1 - native
mui-docs - native
strada-build-src - native
strada-compiler - native
ts-pre-modules - native
vscode - native
webpack - native
xstate-main - native

_Benchmark	_Name	_Iterations
_Current	_pr	₁₂
_Baseline	_baseline	₁₂

Developer Information:

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typescript-automation Bot assigned Jake Bailey (jakebailey) Oct 8, 2026

typescript-automation Bot added Author: Team For Uncommitted Bug PR for untriaged, rejected, closed or missing bug labels Oct 8, 2026

Jake Bailey (jakebailey) added 6 commits October 15, 2026 09:37

Intern symbol names with unique handles

8fcba31

Symbols should share canonical names so identity checks and symbol-table lookups do not repeatedly compare string contents. Preserve textual behavior for diagnostics, emitted output, and the JavaScript API.

Hoist fixed symbol names and preserve handle boundaries

6aa39da

Known names and intermediate name operations should stay interned; repeated interning and string round trips defeat the canonical representation in frequently used lookup paths.

Jake Bailey (jakebailey) force-pushed the intern-symbol-names branch from 23581b2 to 7428ff5 Compare October 15, 2026 16:55

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Switch to `type SymbolName unique.Handle[string]` - #64699

Switch to `type SymbolName unique.Handle[string]`#64699
Jake Bailey (jakebailey) wants to merge 7 commits into
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jakebailey:intern-symbol-names

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