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Narrow overload-error and symbol-use ranges to terminal identifier#19505

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Narrow overload-error and symbol-use ranges to terminal identifier#19505
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Copilot AI commented Mar 26, 2026 •
edited by T-Gro
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Fixes #14284, #3920

Problem

The FS0041 'No overloads match for method' error covered the entire expression including object access chains and arguments. For T.Instance.Method(""), the error underlined everything from T to ). This is especially problematic on larger expressions where the wide error range hides other diagnostics.

Similarly, FSharpSymbolUse ranges reported through the name-resolution sink (used by Find Usages, symbol highlight, and semantic classification) covered the whole dotted long-identifier span instead of just the terminal identifier.

Changes

NameResolution.fs/fsi

  • ComputeItemRange now returns (itemRange, itemIdentRange):
    • itemRange: structural whole-long-id span for typed-tree construction (unchanged behavior)
    • itemIdentRange: terminal identifier's own source range for diagnostics and sink reporting
  • ResolveLongIdentAsExprAndComputeRange and ResolveExprDotLongIdentAndComputeRange propagate itemIdentRange and use it for CallMethodGroupNameResolutionSink

CheckExpressions.fs

  • TcMethodApplication: intercepts UnresolvedOverloading errors and narrows the range from the whole expression to just the method name, with guards for multiline expressions, generic constructors, and backtick-escaped names

ServiceParamInfoLocations.fs

  • getAllCurriedArgsAtPosition: updated to handle narrowed symbol-use ranges by checking whether pos falls within the leaf function expression's range (excluding infix applications)

Tests

  • 7 new regression tests in OverloadResolutionErrorRangeTests.fs
  • Updated baselines across the test suite

Before

Error underlines T.Instance.Method("") — the entire expression.

After

Error underlines only Method — the method name.

Copilot AI requested a review from T-Gro March 26, 2026 22:17
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T-Gro commented Mar 27, 2026

@copilot : Try again

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T-Gro commented Mar 27, 2026

@copilot : Try again.

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abonie commented Mar 31, 2026

@copilot Try again

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Copilot AI commented Mar 31, 2026

@copilot Try again

Implemented the fix in commit aa4c1a9. The UnresolvedOverloading error range is now narrowed from the whole expression (mMethExpr) to just the method name identifier by computing the method-name-only range from mItem.End and methodName.Length in TcMethodApplication.

For T.Instance.Method(""), the error now covers only Method (Col 12-18) instead of the entire T.Instance.Method("") expression (Col 1-22). Added 4 regression tests covering instance calls, static calls, chained expressions, and lambda arguments. Tests and compiler build pass. Release notes and full test suite validation still pending.

Copilot AI changed the title [WIP] Copilot Request Narrow 'No matching overload' error range to method name only Mar 31, 2026
Copilot AI requested a review from abonie March 31, 2026 14:46
@T-Gro T-Gro force-pushed the copilot/fix-9141961-29048891-ac83c611-04a8-4bbc-9d1f-393ac1d7c4ba branch from aa4c1a9 to 7d2f1e9 Compare April 9, 2026 12:56
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github-actions Bot commented Apr 9, 2026 •
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❗ Release notes required

✅ Found changes and release notes in following paths:

Change path Release notes path Description
src/Compiler docs/release-notes/.FSharp.Compiler.Service/11.0.100.md

auduchinok
auduchinok reviewed Apr 9, 2026
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Comment thread src/Compiler/Checking/Expressions/CheckExpressions.fs Outdated
@T-Gro T-Gro force-pushed the copilot/fix-9141961-29048891-ac83c611-04a8-4bbc-9d1f-393ac1d7c4ba branch 4 times, most recently from 2751d6e to 47b948d Compare April 16, 2026 07:44
@T-Gro T-Gro force-pushed the copilot/fix-9141961-29048891-ac83c611-04a8-4bbc-9d1f-393ac1d7c4ba branch 2 times, most recently from a5ac31e to fc504b7 Compare April 21, 2026 06:38
@T-Gro T-Gro marked this pull request as ready for review April 21, 2026 06:39
@T-Gro T-Gro requested a review from a team as a code owner April 21, 2026 06:39
@T-Gro T-Gro force-pushed the copilot/fix-9141961-29048891-ac83c611-04a8-4bbc-9d1f-393ac1d7c4ba branch from bfeba1a to e89bb2d Compare April 21, 2026 07:58
T-Gro added a commit that referenced this pull request Apr 21, 2026
@T-Gro
Narrow name-resolution sink range to terminal identifier (#3920)
e69fb3e 
Addresses reviewer feedback on PR #19505:
- r3058446895 / r3058471629: compute narrow ident range in name resolution
  so diagnostics and tooling (Find Usages, symbol highlight, FSharpSymbolUse)
  report on the item name rather than the full long-identifier path.

Approach: ComputeItemRange now returns (itemRange, itemIdentRange):
- itemRange (wide, unchanged) flows into typed-tree construction, sequence
  points, and the delay-rest continuation. Structural ranges and the debug
  experience are untouched.
- itemIdentRange (narrow, terminal ident) is consumed only by the
  CallMethodGroupNameResolutionSink / CallNameResolutionSink calls and
  RegisterUnionCaseTesterForProperty. This fixes #3920 at the source.

The PR #19505 post-hoc trim for FS0041 'No overloads match' is retained
because it narrows the overload-resolution diagnostic via column arithmetic
and is orthogonal to the sink narrowing.

FindReferences test expectations updated for 7 cases to reflect the
newly-correct narrow symbol-use ranges.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
@T-Gro T-Gro force-pushed the copilot/fix-9141961-29048891-ac83c611-04a8-4bbc-9d1f-393ac1d7c4ba branch from 09db23f to 18ae276 Compare April 22, 2026 08:20
T-Gro added a commit that referenced this pull request Apr 22, 2026
@T-Gro
Narrow name-resolution sink range to terminal identifier (#3920)
d2ee760 
Addresses reviewer feedback on PR #19505:
- r3058446895 / r3058471629: compute narrow ident range in name resolution
  so diagnostics and tooling (Find Usages, symbol highlight, FSharpSymbolUse)
  report on the item name rather than the full long-identifier path.

Approach: ComputeItemRange now returns (itemRange, itemIdentRange):
- itemRange (wide, unchanged) flows into typed-tree construction, sequence
  points, and the delay-rest continuation. Structural ranges and the debug
  experience are untouched.
- itemIdentRange (narrow, terminal ident) is consumed only by the
  CallMethodGroupNameResolutionSink / CallNameResolutionSink calls and
  RegisterUnionCaseTesterForProperty. This fixes #3920 at the source.

The PR #19505 post-hoc trim for FS0041 'No overloads match' is retained
because it narrows the overload-resolution diagnostic via column arithmetic
and is orthogonal to the sink narrowing.

FindReferences test expectations updated for 7 cases to reflect the
newly-correct narrow symbol-use ranges.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
@T-Gro
Narrow overload-error and symbol-use ranges to terminal identifier (#…
55769f8 
…14284, #3920)

Narrow the FS0041 'No overloads match' error range from the whole expression
to just the method name. For T.Instance.Method(""), the error now covers only
'Method' instead of 'T.Instance.Method("")'.

Also narrow name-resolution sink ranges (used by Find Usages, symbol highlight,
and semantic classification) to the terminal identifier of a dotted long
identifier instead of the whole object-expression path.

Changes:
- NameResolution.fs: ComputeItemRange now returns (itemRange, itemIdentRange).
  itemRange is the structural whole-long-id span for typed-tree construction.
  itemIdentRange is the terminal identifier's range for diagnostics and sinks.
- CheckExpressions.fs: Intercept UnresolvedOverloading errors in
  TcMethodApplication and narrow the error range to the method name.
- ServiceParamInfoLocations.fs: Update getAllCurriedArgsAtPosition to handle
  narrowed symbol-use ranges by also checking the leaf function expression.

Fixes #14284, #3920

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
@T-Gro T-Gro changed the title Narrow 'No matching overload' error range to method name only Narrow overload-error and symbol-use ranges to terminal identifier Apr 22, 2026
@T-Gro T-Gro force-pushed the copilot/fix-9141961-29048891-ac83c611-04a8-4bbc-9d1f-393ac1d7c4ba branch from 5b96681 to 55769f8 Compare April 22, 2026 11:21
abonie
abonie reviewed Apr 30, 2026
View reviewed changes
Comment thread src/Compiler/Checking/Expressions/CheckExpressions.fs

// mItem is the textual range covered by the long identifiers that make up the item
and TcItemThen (cenv: cenv) (overallTy: OverallTy) env tpenv (tinstEnclosing, item, mItem, rest, afterResolution) staticTyOpt delayed =
and TcItemThen (cenv: cenv) (overallTy: OverallTy) env tpenv (tinstEnclosing, item, mItem, _mItemIdent, rest, afterResolution) staticTyOpt delayed =
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What's the point of adding this parameter (_mItemIdent) that's only discarded?

@github-project-automation github-project-automation Bot moved this from New to In Progress in F# Compiler and Tooling Apr 30, 2026
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'No matching overload' error has too wide range

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