Terraform issue: Maps not coerced to objects for input variables

trace.txt

2020/02/12 16:56:27 [INFO] Terraform version: 0.12.20  
2020/02/12 16:56:27 [INFO] Go runtime version: go1.13.6
2020/02/12 16:56:27 [INFO] CLI args: []string{"/usr/local/bin/terraform", "validate"}
2020/02/12 16:56:27 [DEBUG] Attempting to open CLI config file: /Users/dave/.terraformrc
2020/02/12 16:56:27 [DEBUG] File doesn't exist, but doesn't need to. Ignoring.
2020/02/12 16:56:27 [INFO] CLI command args: []string{"validate"}
2020/02/12 16:56:27 [DEBUG] checking for provider in "."
2020/02/12 16:56:27 [DEBUG] checking for provider in "/usr/local/bin"
2020/02/12 16:56:27 [DEBUG] checking for provisioner in "."
2020/02/12 16:56:27 [DEBUG] checking for provisioner in "/usr/local/bin"
2020/02/12 16:56:27 [INFO] Failed to read plugin lock file .terraform/plugins/darwin_amd64/lock.json: open .terraform/plugins/darwin_amd64/lock.json: no such file or directory
2020/02/12 16:56:27 [TRACE] terraform.NewContext: starting
2020/02/12 16:56:27 [TRACE] terraform.NewContext: resolving provider version selections
2020/02/12 16:56:27 [TRACE] terraform.NewContext: loading provider schemas
2020/02/12 16:56:27 [TRACE] terraform.NewContext: complete
2020/02/12 16:56:27 [INFO] terraform: building graph: GraphTypeValidate
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.ConfigTransformer
2020/02/12 16:56:27 [TRACE] ConfigTransformer: Starting for path: 
2020/02/12 16:56:27 [TRACE] ConfigTransformer: Starting for path: child
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.ConfigTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.LocalTransformer
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.LocalTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.OutputTransformer
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.OutputTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.OrphanResourceInstanceTransformer
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.OrphanResourceInstanceTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.StateTransformer
2020/02/12 16:56:27 [TRACE] StateTransformer: state is empty, so nothing to do
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.StateTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.OrphanOutputTransformer
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.OrphanOutputTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.AttachResourceConfigTransformer
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.AttachResourceConfigTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.AttachStateTransformer
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.AttachStateTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.RootVariableTransformer
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.RootVariableTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.MissingProvisionerTransformer
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.MissingProvisionerTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.ProvisionerTransformer
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.ProvisionerTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.ModuleVariableTransformer
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.ModuleVariableTransformer with new graph:
  module.child.var.foo - *terraform.NodeApplyableModuleVariable
  ------
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.graphTransformerMulti
2020/02/12 16:56:27 [TRACE] (graphTransformerMulti) Executing graph transform *terraform.ProviderConfigTransformer
2020/02/12 16:56:27 [TRACE] (graphTransformerMulti) Completed graph transform *terraform.ProviderConfigTransformer with new graph:
  module.child.var.foo - *terraform.NodeApplyableModuleVariable
  ------
2020/02/12 16:56:27 [TRACE] (graphTransformerMulti) Executing graph transform *terraform.MissingProviderTransformer
2020/02/12 16:56:27 [TRACE] (graphTransformerMulti) Completed graph transform *terraform.MissingProviderTransformer (no changes)
2020/02/12 16:56:27 [TRACE] (graphTransformerMulti) Executing graph transform *terraform.ProviderTransformer
2020/02/12 16:56:27 [TRACE] (graphTransformerMulti) Completed graph transform *terraform.ProviderTransformer (no changes)
2020/02/12 16:56:27 [TRACE] (graphTransformerMulti) Executing graph transform *terraform.PruneProviderTransformer
2020/02/12 16:56:27 [TRACE] (graphTransformerMulti) Completed graph transform *terraform.PruneProviderTransformer (no changes)
2020/02/12 16:56:27 [TRACE] (graphTransformerMulti) Executing graph transform *terraform.ParentProviderTransformer
2020/02/12 16:56:27 [TRACE] (graphTransformerMulti) Completed graph transform *terraform.ParentProviderTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.graphTransformerMulti (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.RemovedModuleTransformer
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.RemovedModuleTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.AttachSchemaTransformer
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.AttachSchemaTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.ReferenceTransformer
2020/02/12 16:56:27 [DEBUG] ReferenceTransformer: "module.child.var.foo" references: []
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.ReferenceTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.CountBoundaryTransformer
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.CountBoundaryTransformer with new graph:
  meta.count-boundary (EachMode fixup) - *terraform.NodeCountBoundary
    module.child.var.foo - *terraform.NodeApplyableModuleVariable
  module.child.var.foo - *terraform.NodeApplyableModuleVariable
  ------
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.TargetsTransformer
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.TargetsTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.ForcedCBDTransformer
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.ForcedCBDTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.CloseProviderTransformer
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.CloseProviderTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.CloseProvisionerTransformer
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.CloseProvisionerTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.RootTransformer
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.RootTransformer (no changes)
2020/02/12 16:56:27 [TRACE] Executing graph transform *terraform.TransitiveReductionTransformer
2020/02/12 16:56:27 [TRACE] Completed graph transform *terraform.TransitiveReductionTransformer (no changes)
2020/02/12 16:56:27 [DEBUG] Starting graph walk: walkValidate
2020/02/12 16:56:27 [TRACE] dag/walk: updating graph
2020/02/12 16:56:27 [TRACE] dag/walk: added new vertex: "module.child.var.foo"
2020/02/12 16:56:27 [TRACE] dag/walk: added new vertex: "meta.count-boundary (EachMode fixup)"
2020/02/12 16:56:27 [TRACE] dag/walk: added edge: "meta.count-boundary (EachMode fixup)" waiting on "module.child.var.foo"
2020/02/12 16:56:27 [TRACE] dag/walk: dependencies changed for "meta.count-boundary (EachMode fixup)", sending new deps
2020/02/12 16:56:27 [TRACE] dag/walk: visiting "module.child.var.foo"
2020/02/12 16:56:27 [TRACE] vertex "module.child.var.foo": starting visit (*terraform.NodeApplyableModuleVariable)
2020/02/12 16:56:27 [TRACE] vertex "module.child.var.foo": evaluating
2020/02/12 16:56:27 [TRACE] [walkValidate] Entering eval tree: module.child.var.foo
2020/02/12 16:56:27 [TRACE] <root>: eval: *terraform.EvalSequence
2020/02/12 16:56:27 [TRACE] <root>: eval: *terraform.EvalOpFilter
2020/02/12 16:56:27 [TRACE] <root>: eval: *terraform.EvalModuleCallArgument
2020/02/12 16:56:27 [ERROR] <root>: eval: *terraform.EvalModuleCallArgument, err: Invalid value for module argument: The given value is not suitable for child module variable "foo" defined at child/child.tf:1,1-15: object required.
2020/02/12 16:56:27 [ERROR] <root>: eval: *terraform.EvalOpFilter, err: Invalid value for module argument: The given value is not suitable for child module variable "foo" defined at child/child.tf:1,1-15: object required.
2020/02/12 16:56:27 [ERROR] <root>: eval: *terraform.EvalSequence, err: Invalid value for module argument: The given value is not suitable for child module variable "foo" defined at child/child.tf:1,1-15: object required.
2020/02/12 16:56:27 [TRACE] [walkValidate] Exiting eval tree: module.child.var.foo
2020/02/12 16:56:27 [TRACE] vertex "module.child.var.foo": visit complete
2020/02/12 16:56:27 [TRACE] dag/walk: upstream of "meta.count-boundary (EachMode fixup)" errored, so skipping

Error: Invalid value for module argument

  on main.tf line 3, in module "child":
   3:   foo    = map("bar", "baz")

The given value is not suitable for child module variable "foo" defined at
child/child.tf:1,1-15: object required.