Add support for inline() parameter overrides in .bicepparam files

[polatengin]

Adding an inline() function to .bicepparam files that allows parameter values to be provided at deployment time through the BICEP_PARAMETERS_OVERRIDES environment variable (populated by Azure CLI from command-line arguments).

The function acts as a placeholder during authoring but gets replaced with actual values during compilation.

az deployment sub create --location eastus \
  --template-file main.bicep \
  --parameters @prod.bicepparam sku=Basic location=westus

The CLI passes these overrides (sku=Basic and location=westus) to the Bicep compiler through the BICEP_PARAMETERS_OVERRIDES environment variable as json.

Example usage

param <name> = inline()

The inline() function:

• Takes zero arguments
• Returns type any during static analysis
• Is only valid in parameter assignment expressions in .bicepparam files
• Acts as a marker/placeholder for runtime replacement

Implementation details;

Direct assignment (Parameter name)
param foo = inline() → uses foo from overrides

Object property (Property name)
param foo = { key1: inline() } → uses key1 from overrides

Array element (Parameter name)
param foo = [inline()] → uses foo from overrides

Nested objects (Property chain)
param foo = { nested: { key: inline() } } → uses nested.key from overrides

Details

• Implement InlineFunctionValidator to validate inline() usage (allowed only in parameter assignments in .bicepparam; errors for variables, string interpolation, and missing overrides)
• Add LanguageConstants.InlineKeyword and register inline() function in the system namespace
• Implement InlineReplacementRewriter in ParamsFileHelper to replace inline() with CLI-provided parameter overrides when building params
• Hook inline function validation into EmitLimitationCalculator
• Add diagnostics for BCP442/BCP443/BCP444 with clear error messages
• Add integration tests covering inline() success and failure scenarios (inline in params, objects, arrays; and invalid usages)
• Minor whitespace/newline fixes in several test and extension files

Fixes #10454

Checklist

• I have read and adhere to the contribution guide.

Microsoft Reviewers: Open in CodeFlow

[github-actions]

Test this change out locally with the following install scripts (Action run 18954797366)

VSCode

• Mac/Linux

  bash <(curl -Ls https://aka.ms/bicep/nightly-vsix.sh) --run-id 18954797366

• Windows

  iex "& { $(irm https://aka.ms/bicep/nightly-vsix.ps1) } -RunId 18954797366"

Azure CLI

• Mac/Linux

  bash <(curl -Ls https://aka.ms/bicep/nightly-cli.sh) --run-id 18954797366

• Windows

  iex "& { $(irm https://aka.ms/bicep/nightly-cli.ps1) } -RunId 18954797366"

[github-actions]

Dotnet Test Results

    96 files   -     48      96 suites   - 48   42m 26s ⏱️ - 33m 58s
12 532 tests  -      6  12 532 ✅  -      6  0 💤 ±0  0 ❌ ±0 
28 809 runs   - 14 377  28 809 ✅  - 14 377  0 💤 ±0  0 ❌ ±0 

Results for commit eb39686. ± Comparison against base commit 8ea021c.

This pull request removes 1954 and adds 668 tests. Note that renamed tests count towards both.

		nestedProp1: 1
		nestedProp2: 2
		prop1: true
		prop2: false
	1
	2
	\$'")
	prop1: true
	prop2: false
…

Bicep.Cli.IntegrationTests.BuildParamsCommandTests ‑ Build_params_with_inline_array_succeeds
Bicep.Cli.IntegrationTests.BuildParamsCommandTests ‑ Build_params_with_inline_but_no_override_fails
Bicep.Cli.IntegrationTests.BuildParamsCommandTests ‑ Build_params_with_inline_function_succeeds
Bicep.Cli.IntegrationTests.BuildParamsCommandTests ‑ Build_params_with_inline_in_object_property_succeeds
Bicep.Cli.IntegrationTests.BuildParamsCommandTests ‑ Build_params_with_inline_in_string_interpolation_fails
Bicep.Cli.IntegrationTests.BuildParamsCommandTests ‑ Build_params_with_inline_in_variable_fails
Bicep.Cli.IntegrationTests.BuildParamsCommandTests ‑ Build_params_with_inline_type_mismatch_fails
Bicep.Cli.UnitTests.Services.ReplEnvironmentTests ‑ ShouldSubmitBuffer_terminates_at_expected_point ("var foo = {
")
Bicep.Cli.UnitTests.Services.ReplEnvironmentTests ‑ ShouldSubmitBuffer_terminates_at_expected_point ("var multilineString = '''
Line 1
Line 2
Line 3
'''")
Bicep.Cli.UnitTests.Services.ReplEnvironmentTests ‑ ShouldSubmitBuffer_terminates_at_expected_point ("var outRoleAssignments object[] = union(map(
  filter(varMockedEntraGroupIds, item => !contains(item.uniqueName, 'DevOps')),
  group => {
    principalId: group.groupId
    definition: group.roleToAssign
    relativeScope: ''
    principalType: 'Group'
  }
),[
  {
    principalId: '22222222-2222-2222-2222-222222222222'
    definition: 'Reader'
    relativeScope: ''
    principalType: 'ServicePrincipal'
  }
])")
…